S e p te m b e r 1 8 -2 1 , 2 0 1 2 U n iv e rs ity o f G ra z...The Higgs Boson search at the LHC: results and perspectives 4 Pr ogr amme of the 62nd Annual Mee ting ÖPG 2012 Thursday

Karl-Franzens-Universitat Graz

ReSoWi-Zentrum, Universitatsstrasse 15

8010 Graz, Austria

Impressum

Herausgeber Fur die OPG:Michael RamseyKarl-Franzens-Universitat GrazInstitut fur PhysikSurface- and Interface PhysicsUniversitatsplatz 58010 GrazAustria

Tel: +43 316 380 5203Fax: +43 316 380 9816E-mail: [email protected]

Layout M. Wagner, A. Windisch

Druck Karl-Franzens-Universitat Graz

Danksagung / Acknowledgements

Die Organisatoren danken fur die freundliche Unterstutzung von:

The organizers wish to thank the support of:

Organisation Committee

Michael RamseyGeorg Koller

Joachim KrennLeopold Mathelitsch

Reinhard AlkoferFalko Netzer

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Contents

1 Allgemeine Informationen / General information . . . . . . . . . . 9

2 Plenary SessionsHS 15.03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3 Energy (AKE): Energietag “Mehr Licht!”HS 15.03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

4 Nuclear and Particle Physics (FAKT)Tue: HS 15.02; Thu, Fri: HS 15.03 . . . . . . . . . . . . . . . . . . . . . . 35

5 Physics Teachers (LHS)HS 15.02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

6 Acoustics (AKU)LS 15.02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

7 Atoms, Molecules, Quantum Optics and Plasmas (AMP)LS 15.01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

8 Solid State Physics (FKP) &Research with Neutron and Synchrotron Radiation (NESY)HS 15.12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

9 History of Physics (GEP)HS 05.01 (Physics Building) . . . . . . . . . . . . . . . . . . . . . . . . . . 103

10 Medical, Bio and Environmental Physics (MBU)SR 15.15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

11 Surfaces, Interfaces and Thin Films (OGD)HS 15.02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

12 Careers in Physics (PIE)HS 15.03 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

13 Posters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

14 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

15 Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187

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1 Allgemeine Informationen / General information

Aktuelle Informationen konnen von der Website der Konferenz abgerufen werden:http://www.oepg.at

Actual information can be downloaded from the conference website:http://www.oepg.at

Tagungsort

Die Jahrestagung der Osterreichischen Physikalischen Gesellschaft findet an derKarl-Franzens-Universitat Graz, ReSoWi-Zentrum, Universitatsstrasse 15 C, 8010Graz, Osterreich, statt. Das Tagungsburo befindet sich fur die Dauer der Jahresta-gung im Gang C. Den Campus- und Raumplan des ReSoWi-Zentrums finden Sie amEnde dieses Tagungsbandes.Die Theaterauffuhrung “Kosmische Strahlen: Das Leben des Victor F. Hess” sowiedie Sitzung der Arbeitsgruppe GEP (History of Physics) finden im Horsaal 05.01des Physikinstitutes statt. Das UniGraz@Museum befindet sich im Hauptgebaudeund ist uber den Seiteneingang zu betreten (siehe Campusplan).

Vom Hauptbahnhof Graz aus kann die Universitat mit den Bussen 63 (Haltestelle“Universitat”) oder 58 (Haltestelle “Mozartgasse”) erreicht werden (Fahrtdauer: 15–25 Minuten). Die Haltestellen sind im Campusplan eingezeichnet.Des weiteren befinden sich vor dem Hauptbahnhof und vor dem Hauptgebaude derUniversitat Taxis.

Conference venue

The Annual Meeting of the Austrian Physical Society is held at the University ofGraz, ReSoWi-Zentrum, Universitatsstrasse 15 C, 8010 Graz, Austria. The con-ference office is situated at the entrance of the ReSoWi building, floor C, for theduration of the conference. A map of the campus and the ReSoWi center is addedat the end of this book.The play “Kosmische Strahlen: Das Leben des Victor F. Hess” as well as the sessionof the working group GEP (History of Physics) take place in the lecture hall 05.01of the physical institute. The UniGraz@Museum is situated in the main buildingand can be entered via the side entrance indicated in the campus map.

At the railway station of Graz (“Hauptbahnhof Graz”) take the bus 63 until tothe bus stop “Universitat” or 58 to the stop “Mozartgasse” (time required: 15–25minutes). Bus stops are indicated in the campus map.Moreover, in the front of the railway station as well as in front of the main buildingof the university are also taxi stands.

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Tagungsgebuhren / Conference fees

Kategorie Vor 31. Juli Nach 31. JuliCategory Before 31 July After 31 July

OPG Mitglieder, assoz. MitgliederOPG members, assoc. members

EURO 70 EURO 80

Mitglieder im RuhestandOPG retired members

EURO 35 EURO 40

Nicht-MitgliederOPG non-members

EURO 90 EURO 100

LehrerTeacher EURO 15 EURO 20

Bachelor und Master StudentenBachelor and Master students frei/free frei/free

DoktorandenPh.D. students EURO 15 EURO 20

TagesgebuhrDaily fee EURO 35 EURO 35

Tagesgebuhr DoktorandenDaily fee for Ph.D. students EURO 10 EURO 10

Anmeldung und Zahlungsmodalitaten / Registration and Pay-ment

Bankuberweisung an / Payments should be made to:Universitaet GrazBank AustriaIBAN: AT32 1200 0500 9550 0605BIC: BKAUATWWVerwendungszweck / Reference: OePG2012 + A28165301035+participant’s names

Bei der Tagesrezeption: Es wird um Bargeld ersucht. Die Anmeldung vor Ortbeginnt am Dienstag, 18. September 9:00–16:30, Mittwoch, 19. September 8:30–16:30, Donnerstag, 20. September 8:30–16:30, und Freitag, 21. September 8:30–12:00(siehe auch Tagungsprogramm).

At the conference registration: You are kindly requested to pay in cash at theregistration. The registration times are as follows: Tuesday, 18th September 9:00–16:30, Wednesday, 19th September 8:30–16:30, Thursday, 20th September 8:30–16:30,and Friday, 21st September 8:30–12:00 (see also program).

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Reisekostenzuschuss fur studentische OPG-Mitglieder

Studentische OPG-Mitglieder konnen einen Reisekostenzuschuss mittels des im Ta-gungsburo aufliegenden Formulars beantragen (Befurwortung durch Betreuer not-wendig). Die Hohe der Zuschusse richtet sich nach den zur Verfugung stehendenMitteln, der Zahl der Ansuchen sowie der tatsachlichen Hohe der Reisekosten.

Travel support for student members of the OPG

Student members of OPG can apply for travel support via the form available atthe registration. The signature (approval) of the applicants tutor is necessary onthe form. The amount of support depends of the funds available, the number ofapplications and the actual travel costs.

Unterbringungsmoglichkeiten

Unterkunfte in Graz konnen uber http://www.booking.com oder uber Graz Touris-mus, http://www.graztourismus.at, Tel. +43-316-8075-0,E-mail: [email protected] gebucht werden.

Accommodation

Hotels can be booked via http://www.booking.com or the Tourist Office Graz,http://www.graztourismus.at, Tel. +43-316-8075-0,email: [email protected].

Horsale und Ausstattung

Alle Horsale sind mit einem PC und einem Beamer ausgestattet, sodass die Mit-nahme eines USB-Sticks genugt. Das Betriebssystem ist MS Windows XP mit Pow-erPoint als Standard-Prasentations-Software. Sollten Sie ein anderes Betriebssys-tem bzw. eine andere Prasentations-Software benotigen, so ist ein eigenes Notebookmitzubringen. Technische Unterstutzung vor Ort ist moglich.Die Erfahrung zeigt, dass es bei den Beamer-Prasentationen immer wieder zu zeit-lichen Verzogerungen beim Ablauf der Sitzungen kommen kann (Inkompatibilitatenvon Soft- und Hardware, Nicht-Standard-Schriftsatze, etc.). Fur einen reibungslosenAblauf der Fachsitzungen sind die Vorsitzenden der Fachausschusse verantwortlich.

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Lecture rooms and equipment

All lecture rooms are equipped with computer and video projector for which youonly need to bring your USB-stick. The operating system is MS Windows XP withPowerPoint as standard presentation software. Should you need another operationsystem resp. another presentation software it is recommended to supply your ownlaptop. Technical assistance will be available in the lecture rooms.Experience has proved that there are always delays with preparation of lectures dueto incompatibility of software, etc. The chairmen of the topical sessions are respon-sible for the smooth operation of the session.

Poster

Format: Breite max. 97 cm, Hohe max. 147 cm, bzw. A0 Format. Posters konnenbei Beginn der Tagung (Dienstag, 18. Sept. 2012) angebracht werden, und solltenmoglichst bis zum Abend des 20. Sept. 2012 ausgestellt bleiben. Bei der allgemeinenPostersitzung am Mittwoch, 19. Sept. 2012, ab 17:45 Uhr, sollte mindestens ein Au-tor beim Poster anwesend sein.

Der Gewinner des Posterpreises, zur Verfugung gestellt von EPL, wird zu Beginndes Plenarvortrages am Donnerstag um 11:30 bekanntgegeben.

Posters

Format: Width: 97 cm, height 147 cm (A0 format). You can fix your poster on thefirst of day of the conference (Tuesday, 18 Sept. 2012). On Wednesday, 19th Sept.2012, at 17:45 there should be at least one author presenting the poster at the gen-eral poster session.

The cash prize for the best poster will be announced on Thursday, at the begin-ning of the plenary talk at 11:30.

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Buffets und Erfrischungen

Das Buffet wird wahrend der Poster Session am Mittwoch von 17:45–20:00 Uhrgeoffnet sein. Am Donnerstag, von 18:00–20:00 Uhr, werden im Museum der Karl-Franzens-Universitat (UniGraz@Museum) Erfrischungen zur Verfugung stehen.

Buffets and Refreshments

During the poster session on Wednesday, 17:45–20:00, food and drinks will beprovided. Refreshments will be also provided at the University Museum (Uni-Graz@Museum) at the end of the Thursday sessions.

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2 Plenary SessionsHS 15.03

Tuesday, 18th September 2012, HS 15.03

Time Presenter Title

16:30 Opening

17:00James Cronin(Nobel Laureate)

Spontaneous Ionization to Sub-atomic Physics: Some Vignettesfrom Cosmic Ray History

Wednesday, 19th September 2012, HS 15.03


09:00 - 10:00 John SwainCosmic Rays: An Ongoing ClearWindow into New Physics

10:00 - 11:00 Franz Gießibl

Simultaneous atomic force- andscanning tunneling microscopy –a new view on two distinct as-pects of the atomic structure ofmatter

11:20 - 12:30 Prize Award Session

12:30 - 13:30 Lunch Break


13:30 - 13:40Alexander Jesacher

Joint Fritz Kohlrausch Prize

Enhancing image contrast inwide-field CARS microscopy bytailored phase matching

13:40 - 13:50Daniel Kiener

Joint Fritz Kohlrausch Prize

Advances in understandingsmall-scale plasticity throughin-situ TEM

13:50 - 14:10Giuseppe Mercurio

Max Auwarter Prize

Unfolding Molecule-Metal Inter-actions using X-ray StandingWaves

14:10 - 14:30Nicolette Doblhoff-Dier

Roman Ulrich Sexl Prize

Physik erfahren, Physik erleben– auf vielen Wegen zur Physik

14:30 - 15:30 Hans BriegelQuantum physics, simulationand computation

15:30 - 16:00 Coffee break

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Wednesday, 19th September 2012, HS 15.03


16:00 - 16:30 Wolfgang AdamThe Higgs Boson search at theLHC - results and perspectives

16:45 - 17:45 OPG General Assembly of Members

17:45 - 20:00 Poster Session (see chapter Posters)

20:15 Theatre (see page 22), HS 05.01, Physics Building

Thursday, 20th September 2012, HS 15.03


11:30 - 12:30 Vahid SandoghdarOn the efficient interaction ofsingle photons and single emit-ters

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Tue, 17:00 - 18:00, HS 15.03

Tue, 17:00, Plenary

Spontaneous Ionization to Subatomic Physics: SomeVignettes from Cosmic Ray History

James Cronin1,2

1The University of Chicago,The Kavli Institute for Cosmological Physics, 933 East 56th Street, Chicago, IL 60637 USA2Enrico Fermi Institute, University of Chicago, 5640 S. Ellis Avenue, RI-183, Chicago, IL 60637 USA

In the 1879 Crookes discovered that air seemed to ionize spontaneously. With the discoveryin 1896 of radioactivity by Henri Becquerel it appeared that the mystery was solved. However anumber of physicists sought a quantitative agreement between the “spontaneous ionization” andthe radioactivity in the earth. The persistence of these physicists led to the discovery of anothersource of radiation which appeared to come from the heavens. The nature of this “cosmic radi-ation” involved phenomena that were completely unknown. Coming to an understanding of thenature of this cosmic radiation took about 40 years between 1912 and 1953. This history involvesextraordinary scientists and the invention of dramatic new detection techniques. The story finisheswith a remarkable conference organized by Patrick Blackett and Louis Leprince-Ringuet 1953 inthe Pyrenees town of Bagneres de Bigorre.

James Cronin and co-researcher Val Logsdon Fitch were awarded the 1980 Nobel Prize in Physicsfor a 1964 experiment that proved that certain subatomic reactions do not adhere to fundamentalsymmetry principles. Specifically, they proved, by examining the decay of kaons, that a reactionrun in reverse does not merely retrace the path of the original reaction, which showed that theinteractions of subatomic particles are not indifferent to time. Thus the phenomenon of CP vi-olation was discovered. Cronin received the Ernest Orlando Lawrence Award in 1976 for majorexperimental contributions to particle physics including fundamental work on weak interactionsculminating in the discovery of asymmetry under time reversal. He is Professor Emeritus at theUniversity of Chicago and a spokesperson emeritus for the Auger project. The Pierre Auger Ob-servatory, which he proposed, is an international cosmic ray observatory spread over 3000 squarekilometers in Argentina, designed to detect ultra-high-energy cosmic rays.

Wed, 09:00 - 10:00, HS 15.03

Wed, 09:00, Plenary

Cosmic Rays: An Ongoing Clear Window into New PhysicsJohn Swain1

1Northeastern University, Physics Department, 360 Huntington Ave, 111 Dana Research Center, Boston, MA 02115, USA

Since Victor Hess’s pioneering work in 1912, cosmic rays have provided not only a window intoenergetic processes in space, but also the first glimpses of many aspects of particle physics. Thistalk reviews and highlights some of the major achievements in the field, what has been learned,and what major scientific puzzles remain, emphasizing the uniqueness of cosmic rays as a probe ofboth exotic objects in the far reaches of the universe, and into the deep heart of matter beyond thereach of even modern terrestrial particle accelerators. An outlook for the future is given showingthat cosmic ray physics will continue to provide key insights into nature unavailable through anyother means.

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Wed, 10:00 - 11:00, HS 15.03

Wed, 10:00, Plenary

Simultaneous atomic force- and scanning tunnelingmicroscopy – a new view on two distinct aspects of the

atomic structure of matterFranz Gießibl1

1University of Regensburg, Faculty of Natural and Applied Physics II - Physics, Universitatsstrasse 31, D-93053 Regensburg, Germany

Frequency-modulation AFM can be combinedwith scanning tunneling microscopy, yielding asimultaneous data set for current and averageforce gradient. Ternes et al. [1] have shown thatfor some metallic contacts, force and currentare proportional. The figure below [2] showsan example, where combined AFM/STM re-veals two strongly distinct aspects of the atomicstructure of matter. The gray veil depictsthe inverted tunneling current between a COmolecule adsorbed on Cu(111) and a tungstentip, while the colored surface shows the cor-responding force profiles, where the left imagecorresponds to a W tip oriented in a 〈100〉 di-rection, the right to a 〈110〉 direction and thebottom to a 〈111〉 direction [3]. While the si-multaneous acquisition of current and force canreveal new information about the atomic andelectronic structure of matter, the tunnelingcurrent can modify the atomic forces.

This “phantom force” [4,5], a modification of the electrostatic attraction between tipand sample, originates in an alteration of the effective potential difference between tipand sample caused by strongly localized voltage drop induced by the tunneling cur-rent. The talk discusses the merits of combined STM/AFM as well as the challenges,in particular with respect to tip preparation and characterization.

[1] M. Ternes et al., Phys. Rev. Lett. 106, 016802 (2011).[2] Created by Joachim Welker (2012).[3] J. Welker, F.J. Giessibl, Science 326, 444 (2012).[4] A.J. Weymouth et al. Phys. Rev. Lett. 106, 226801 (2011).[5] T. Wutscher et al. Phys. Rev. B 85, 195426 (2012).

Wed, 11:00 - 11:20, Coffee break

Wed, 11:20 - 12:30, HS 15.03, Prize Award SessionFritz Kohlrausch Prize, Victor Franz Hess Prize, Anton Paar Prize, Max Auwarter Prize,

Roman Ulrich Sexl Prize, Young Physicists’ Tournament, Physics Olympiad,Physik-Fachbereichsarbeiten

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Wed, 12:30 - 13:30, Lunch break

Wed, 13:30 - 14:30, HS 15.03, Prize Winner Talks

Wed, 13:30, Joint Fritz Kohlrausch Prize Winner

Enhancing image contrast in wide-field CARS microscopy bytailored phase matching

Alexander Jesacher1, Clemens Roider1, Saranjam Kahn1, Gregor Thalhammer1, Stefan Bernet1,Monika Ritsch-Marte1

1Innsbruck Medical University, Division of Biomedical Physics, Mullerstrasse 44, 6020 Innsbruck, Austria

Coherent anti Stokes Raman scattering (CARS) is a four-wave mixing process that allowsidentifying the chemical composition of target substances by recording their molecular vibrationalspectra. Combined with microscopy, this technique opens a door to investigating specimens atmicrometer scale. A sensitivity limit in CARS microscopy is commonly set by the non-resonantbackgrounda parasitic signal component that arises from off-resonantly driven molecular vibrationsand/or electronic transitions. In particular for the application of investigating small particles, thenon-resonant background generated in the immersion liquid can easily overwhelm the signal of theparticles. We introduce a wide-field CARS microscope implementation that allows for effectivesuppression of the solvent signal by precisely controlling the pump/probe beam incidence angles.Our method relies on the fact that the importance of phase-matching for CARS increases with thesize of the target object. Thus, de-tuning these angles by only as much as a degree can lead to asignificant loss in the undesired solvent signal while leaving that of the particles almost unaltered.We present experimental results where the ratio of the signals of 500nm polystyrene beads and thesurrounding solvent was improved by a factor of about 100.

Wed, 13:40, Joint Fritz Kohlrausch Prize Winner

Advances in understanding small-scale plasticity throughin-situ TEM

Daniel Kiener1

1Montanuniversitat Leoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

The uncommon mechanical properties of small volumes, in particular their size-dependentstrength and hardening behavior, have received significant interest over the last few years. Toexploit these effects for future design of nano-structured materials, it is detrimental to understandthe underlying deformation mechanisms that govern the observed sample size effects in micron-and sub-micron dimensions. Miniaturized tensile and compression samples were fabricated using afocused ion beam microscope and tested in-situ in a transmission electron microscope. Besides pro-viding precise mechanical data, such highly localized in-situ experiments allow to directly observethe dynamics of crystal defects in real time, and to correlate them to the mechanical signature,thereby delivering valuable insight regarding the governing strengthening mechanisms. It is shownthat plastic deformation is governed by the operation of spiral dislocation sources at high stresses.The hardening behavior correlates directly to the exhaustion of such dislocation sources and theability to create new sources by dislocation interaction. Finally, it is demonstrated that an inter-nal micro-structural length scale smaller than the sub-micron sample size causes a transition fromsize-dependent to size-independent material properties, allowing to measure bulk properties fromnano-scale samples.

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Wed, 13:50, Max Auwarter Prize Winner

Unfolding Molecule-Metal Interactions using X-ray StandingWaves

Giuseppe Mercurio1,2

1Peter Grunberg Institut (PGI-3), Forschungszentrum Julich, 52425 Julich, Germany2Julich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Julich, Germany

Functional surfaces based on monolayers of organic molecules are currently subject of an intenseresearch effort due to their applications in molecular electronics, sensing and catalysis. Becauseof the strong dependence of organic-based devices on the local properties of the molecule-metalinterface, a direct investigation of the interface chemistry is of paramount importance. In thiscontext, the bonding distance, measured by means of the normal incidence x-ray standing wavetechnique (NIXSW), provides a direct access to the molecule-metal interactions. At the sametime, NIXSW adsorption heights are used to benchmark different density functional theory (DFT)schemes and determine the ones with predictive power to be employed for similar systems. The talkwill focus on three molecule-metal interfaces pointing out the physical properties common to othermetal-organic systems. The study of a multifunctional organic molecule (perylenetetracarboxylicacid dianhydride, PTCDA) adsorbed on the Ag(110) surface reveals the presence of two distinctbonding channels which depends on the affinity of the respective part of the molecule towards thesubstrate. The coupling between these bonding channels is probed by means of a local modificationof the Ag(110) surface through alkali induced reconstruction. The delicate balance of intermolec-ular and molecule-substrate interactions for terephthalic acid adsorbed on Cu(100) is investigatedby a combined NIXSW-DFT study that suggests the presence of a substrate-mediated interac-tion, besides the intermolecular H-bonding, as stabilizing force of the molecular islands. Finally,with the aim to better understand the switching properties of photo-active molecules (azobenzenederivatives) adsorbed on metal surfaces, a novel NIXSW analysis scheme, developed to determinethe bonding conformation of complex organic molecules adsorbed on single metal crystals withunprecedented accuracy, is presented.

Wed, 14:10, Roman Ulrich Sexl Prize Winner

Physik erfahren, Physik erleben – auf vielen Wegen zurPhysik

Nicolette Doblhoff-Dier1

1AHS-Professorin fur Physik, Mathematik und Informatik, Gymnasium Maria-Regina, 1190 Wien

Physik im Unterricht soll Interesse, ja sogar Begeisterung hervorrufen, Neugier wecken, genauesBeobachten lehren, logisches Denken fordern, zum Nachdenken und Fragen anregen, Diskussionenvom Zaun brechen und Begreifen ermoglichen. Physik im Unterricht soll neue Welten eroffnen,Zusammenhange zeigen und Brucken schlagen. SchulerInnen wollen in ihren Interessen ange-sprochen werden und erkennen, dass Physik uberall ist, in der Geschichte, Kunst und Religion(Projekt “Physik im Stephansdom”), in der Musik und Mathematik (“Was macht das Klavierwohltemperiert?”), in der Medizin (“Hochenergie und Med-Austron”), ja sogar beim Vereinbarenvon Terminen (“Von Sonnenuhren uber die gregorianische Kalenderreform bis zur Atomuhr”).Einen Schwerpunkt des Vortrags bildet das Projekt “Die vielen Gesichter des Sir Isaac Newton”,in Kooperation mit der Osterreichischen Akademie der Wissenschaften, im Rahmen dessen zahlre-iche wissenschaftliche Plakate entstanden, sowie fiktive Zeitungsartikel, Fernsehdiskussionen undRatsel, die das Leben von Newton aus unterschiedlichen Blickwinkeln betrachten. Die SchulerInnenschauten staunend durch die gebastelten Fernrohre und Mikroskope und diskutierten heftig uber dievon ihnen ubersetzten Originaltexte von Isaac Newton aus dem Trinity-College und Voltaires Buch“Les elemens de la philosophie de Neuton”. Ich mochte zeigen wie wichtig es ist, den SchulerInnenviele unterschiedliche Wege zur Physik zu ermoglichen. Ich mochte sie lehren zu fragen und zustaunen!

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Wed, 14:30 - 15:30, HS 15.03

Wed, 14:30, Plenary

Quantum physics, simulation, and computationHans Briegel1

1Universitat Innsbruck, Institut fur Theoretische Physik, Technikerstrasse 25, 6020 Innsbruck, Austria

The ultimate scope and power of computers will be determined by the laws of physics. Quantumcomputers exploit the rules of quantum mechanics, using quantum coherence and entanglement fornew ways of information processing. Up to date, the realization of these systems requires extremelyprecise control of matter on the atomic scale and a nearly perfect isolation from the environment.The question, to what extent quantum information processing can also be exploited in “natural”and less controlled systems, including biological ones, is exciting but still open. In this talk, Iwill present some of our recent work on (quantum) physically and biologically motivated models ofinformation processing.

Wed, 16:00 - 16:45, HS 15.03

Wed, 16:00, Plenary

The Higgs Boson search at the LHC - results andperspectives

Wolfgang Adam1

1Austrian Academy of Sciences, Nikolsdorfergasse 18, 1050 Vienna, Austria

Two experiments have recently announced the discovery of a new boson with a mass near 125GeV at the CERN LHC. This new particle matches the expectations for the Higgs boson, themissing piece of the Standard Model of particle physics, which has been one of the main targets ofexperiments in the last decades. This talk will give details on the experimental evidence, focussingon results of the Compact Muon Solenoid (CMS) experiment. First measurements of the propertiesof the new particle will be compared to the expectations of the Standard Model. The fundamentalimplications of the existence of a Higgs boson for particle physics will be explained. The plans forfurther measurements of the properties of this boson and the implications for discovery of Physicsbeyond the Standard Model will be discussed.

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Wed, 20:15, HS 05.01 (Physics Building)

Wed, 20:15, HS 05.01 (Physics Building), Theatre Play

Kosmische Strahlen - Das Leben des Victor F. HessKlaus Reitberger1, Stadttheater Kufstein1

1http://www.stadttheater-kufstein.at/de/index.php

Insights into the eventful life and scientific struggle of Victor F. Hess are presented in thisone-hour play. Based on historic accounts and personal letters, the unique character of the muchacclaimed scientist is portrayed through several key episodes of his life. From the famous balloon-flight in 1912 to the research at the Hafelekar-observatory high above Innsbruck, from receivingthe Nobel prize in physics to the dramatic escape from Nazi-Germany on the eve of World War II.Written and directed by a physicist and performed by actors of the Stadttheater Kufstein [1], thisproject attempts to let history and science meet on stage. The play has already been performed inVienna, Innsbruck and Kufstein. Further performance are foreseen in Pollau, Siegen, Berlin andHamburg.

A six-minute video-trailer of the play can be viewed on [2].

The play will be performed in German. An English translation will soon be published by UniversityPress Innsbruck. The German script is already available.

[1] http://stadttheater-kufstein.at/de/kosmische strahlen.php

[2] http://www.youtube.com/watch?feature=player embedded&v=4 8Udh2HoW8.

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Thu, 11:30 - 12:30, HS 15.03

Thu, 11:30, Plenary

On the efficient interaction of single photons and singleemitters

Vahid Sandoghdar1

1Max-Planck Institut, Gunther-Scharowsky-Strasse 1 / Bau 24, 91058 Erlangen, Germany

In the 1990s, many pioneering experiments demonstrated the potential of single organic moleculesembedded in solids as quantum mechanical two-level systems. However, coherent interactions werenot studied because those experiments relied on recording the fluorescence signal, which only ac-cesses populations of the excited state and not the coherences. Recently, we showed theoreticallythat in the linear excitation regime, an atom can block a propagating light beam by up to 100% ifit is confined to an area comparable with its scattering cross section [1]. I will present an overviewof our recent experimental work on the efficient interaction of light and single organic moleculesboth in the near and far fields [2, 3]. We will see that at T<2K, a single molecule can attenuate[2, 3], transmit, amplify [4] or phase-shift [5] a focused laser beam. Furthermore, I will report onthe first direct long-distance communication of two optical emitters via single photons [6]. I willthen discuss strategies for the optimization of the interaction between single photons and singleemitters via, e.g. ultra-high collection efficiency [7, 8] or enhancement of spontaneous emission [9]by using plasmonic and dielectric antennas.

[1] G. Zumofen, et al., Phys. Rev. Lett. 101, 180404 (2008).[2] I. Gerhardt, et al., Phys. Rev. Lett. 98, 033601 (2007).[3] G. Wrigge, et al., Nature Phys. 4, 60 (2008).[4] J. Hwang, et al., Nature 460, 76 (2009).[5] M. Pototschnig, et al. Phys. Rev. Lett. 107, 063001 (2011).[6] Y. Rezus, et al., Phys. Rev. Lett. 108, 093601 (2012).[7] K-G. Lee, et al., Nature Photonics 5, 166 (2011).[8] X-W. Chen, S. Gotzinger, V. Sandoghdar, Opt. Lett. 36, 3545 (2011).[9] X-W. Chen, M. Agio, V. Sandoghdar, Phys. Rev. Lett. 108, 233001 (2012).

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3 Energy (AKE): Energietag “Mehr Licht!”HS 15.03

AKE: Norbert Pillmayr, [email protected]

Tuesday, 18th September 2012, HS 15.03


10:00 - 10:15 Norbert PillmayrMehr Licht! – Das Vorwort zum En-ergietag 2012

10:15 - 10:45 Helmut TributschBio-analoge Energie- und Material-wirtschaft

10:45 - 11:15 Robin HirschlStrom fur die Welt – und wie uns dieSonne dabei helfen kann

11:15 - 11:45 Thomas PoschBedarfsgerecht und energieeffizientbeleuchten

11:45 - 12:15 Johann GerstmannDas kann Sonnenschutz: Energie,Licht und Warme – zum Nulltarif!

12:15 - 12:45 Gunther Leising Leuchtdioden verandern unsere Welt

12:45 - 13:30 Lunch

13:30 - 13:50 HAK/HAS Mistelbach“Oma Gluhbirne, Enkerl LED und derwilde Onkel Scheinwerfer erzahlen”

13:50 - 14:20 Dieter ParthLED – Die Lichtquelle der Zukunft rev-olutioniert auch die Automobilindus-trie!

14:20 - 14:50 Gregor RadingerPHOTO-TEKTUR: QualitativerLichteintrag und photobiologischeGrundlagen fur ArchitektInnen

14:50 - 15:20 Wilfried Pohl Licht und Energie im Gebaude

15:20 - 15:50 Mathias SchafferSmart Lighting for Smart Citizens –Mehr Licht !? und innovative Beleuch-tungskonzepte fur Smart Cities

15:50 - 16:00 Norbert Pillmayr Schlussworte

Tue, 10:00 - 12:45, HS 15.03

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Tue, 10:00

Mehr Licht! - Das Vorwort zum Energietag 2012Norbert Pillmayr1

1KELAG - Karntner Elektrizitats-Aktiengesellschaft, Klagenfurt, Austria

Nach den Energietagen 2010 in Salzburg (Thema: Realisierung der Klimaziele) und 2011in Wien mit dem Schwerpunkt “Energie effizient nutzen” ist 2012 in Graz die – oftmals unter-schatzte – Thematik der Lichtenergie das Hauptthema des Energietags. Licht macht ca. 20% desweltweiten und 14% des europaischen Stromverbrauchs aus. Diverse Innovationen in der Lichttech-nik konnen bei der Erreichung der Kyoto-Ziele helfen, da Kosten gespart, die Umwelt geschutzt unddie Beleuchtungsqualitat verbessert werden. Licht kommt eine wesentliche Bedeutung fur Kom-fort, Emotion, Motivation und Leistungsbereitschaft zu. In gewerblich genutzten Gebauden wieProduktions-, Verkaufs- und Burogebauden entfallen zwischen 30% und 40% auf Energiekosten.Hier konnen durch eine effiziente Lichtgestaltung Energieeinsparungen erzielt und somit Betrieb-skosten gesenkt werden. Energieeffiziente Beleuchtung leistet damit einen wesentlichen Beitrag zurErreichung der Klimaziele. Die Umwelt wird durch verringerten Energieverbrauch und einer Re-duktion der Kohlendioxydbelastung geschont, Kosten werden gesenkt und die Lichtqualitat fur dasWohl des Menschen wird gleichzeitig verbessert. Der Arbeitskreis (AK) Energie ist ein sehr aktiverArbeitskreis in der Osterreichischen Physikalischen Gesellschaft (OPG), der Interessensvertretungder Physiker in Osterreich. Ein dreikopfiger Vorstand vertritt gleichberechtigt Wissenschaft, Indus-trie und Lehre. Zentrales Thema des AK Energie ist die Behandlung der physikalischen Aspekteund Perspektiven von Energiefragen unter besonderer Berucksichtigung der osterreichischen Situ-ation. Diese sollen in Zusammenarbeit mit Vertretern aller relevanten Fachrichtungen diskutiertwerden. Es wird vor allem Konsens in der Einschatzung der naturwissenschaftlich–technologischenAspekte der Energieproblematik angestrebt.

Tue, 10:15

Bio-analoge Energie- und MaterialwirtschaftHelmut Tributsch1,2

1Freie Universitat Berlin, Takustraße 3, 14195 Berlin, Germany2Helmholtz-Zentrum Berlin fur Materialien und Energie Kekulestrasse 5, 12489 Berlin, Germany

Die Menschheit hatte eine reelle Chance, durch massive Forschung, uber eine solar betriebeneEnergie-Wirtschaft, langerfristig ins Gleichgewicht mit der Natur zuruck zu finden. Das von derNatur vorgegebene und uber Hunderte von Jahrmillionen Jahren bewahrte Vorbild beinhaltetdie Spaltung von Wasser mit Licht und die Anhaftung des freigesetzten Wasserstoffs an einenKohlenstoff-Trager, Kohlendioxid, zur Bereitstellung von Energietragern und Baustoffen. Die Um-setzung dieser Produkte durch die Pflanzen- und Tierwelt fuhrt zu geschlossenen, nachhaltigenEnergie-Stoff-Kreislaufen. Sie wird wirksam unterstutzt durch eine Reihe bisher von unserer Tech-nik nicht beherrschte beziehungsweise nicht erschlossenen Technologien. Sie reichen von “kinetisch”funktionierenden Solarzellen, zu photo-katalytischer Wasserspaltung, Kohlendioxid-Fixierung, zueffektiver Energie-Katalyse und “tensiler” Wasser-Technologie. Es wird analysiert, wie die Men-schheit sich diesen von der Natur realisierten Zielen mit zunachst vereinfachten Techniken schrit-tweise annahern konnte. Angelpunkt ware anfangs die massive Bereitstellung von billigem Wasser-stoff, der dann mit vergaster Biomasse zu nachhaltigen Brenn- und Rohstoffen verbunden werdenkonnte. Die gegenwartige Brennstoff-Infrastruktur bliebe im Wesentlichen erhalten. Der Einstiegin diese Natur-nahe Strategie besteht darin, die Quellen hochster nachhaltiger Energiedichte, diesturmischen Meere, fur die Wasserstoff-Gewinnung zu nutzen. Dies ware uber eine Unter-Wasser-Technologie denkbar, bei der nur die sich mit den Wellen bewegenden, energiewandelnden Bojen andie Wasseroberflache reichen. Diese Wasserstoff- Technologie sollte in zwei bis drei Jahrzehnten re-alisierbar sein. Weitere notige und nutzliche Technologien in Richtung einer bio-analogen, globalenEnergiewirtschaft konnten innerhalb dieses Jahrhunderts verfugbar sein. Die Herausforderungenund Vorteile werden diskutiert.

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Tue, 10:45

Strom fur die Welt – und wie uns die Sonne dabei helfen kannRobin Hirschl1

1ENcome Energy Performance GmbH, Klagenfurt, Austria

Die Sonne: Ein gigantischer Kernfusionsreaktor, 150 Millionen Kilometer von der Erde entfernt.Und trotz der Entfernung liefert dieser Reaktor jahrlich mehr als das 10.000-fache des weltweitenBedarfs an Primarenergie. Im Vortrag sollen zunachst die verschiedenen Moglichkeiten solare En-ergie zu nutzen diskutiert werden. Anschließend wird auf die physikalischen und wirtschaftlichenDetails der Photovoltaik naher eingegangen. Sowohl der derzeitige Stand der Technik als auchdie theoretischen Grenzen der Technologie werden beschrieben. In weiterer Folge soll mit einigenVorurteilen rund um die Photovoltaik aufgeraumt werden, wie zum Beispiel dass die Photovoltaikbei der Erzeugung mehr Energie verbraucht als wahrend der Lebensdauer der Anlagen produziertwird, oder dass die Photovoltaik nicht ohne Subventionen wirtschaftlich sein kann. Im zweiten Teilwerden, ausgehend von den derzeitigen technischen und okonomischen Auswirkungen der Imple-mentierung von PV Anlagen in europaische Stromnetze, die Moglichkeiten und Herausforderun-gen von signifikanten PV Kapazitaten im Netzverbund behandelt. Insbesondere mangelt es nochan einer effizienten und langzeitstabilen Moglichkeit zur Energiespeicherung, um Photovoltaik inlokalen autarken Netzen exklusiv einsetzen zu konnen. Andererseits konnen großere Gruppierun-gen von PV Anlagen schon jetzt dazu beitragen, einige der technischen Schwierigkeiten heutigerVerteil- und Ubertragungsnetze zu meistern. Abschließend soll ein Blick in die Zukunft helfen zuverstehen, welche Moglichkeiten realistisch in der Solarenergie stecken und in welchem Kontext eineechte Energiewende hin zu erneuerbaren Energien tatsachlich moglich erscheint.

Tue, 11:15

Bedarfsgerecht und energieeffizient beleuchtenThomas Posch1

1Universitat Wien, Universitatsring 1, 1010 Wien, Austria

Kunstliche Beleuchtung macht unser Leben (scheinbar) leichter: die Gestaltung unserer Arbeits-und Freizeit wird flexibler, sogenannte “Angstraume” verschwinden, Produktionsvorgange konnen- auch ohne Mitternachtssonne - 24 Stunden und 7 Tage pro Woche aufrecht erhalten werden. Erstin den letzten Jahren hat sich durch wissenschaftliche Untersuchungen gezeigt, dass kunstlichesLicht nicht immer und in jeder Menge dem Menschen und der Natur gut tut. Chronobiologen, En-tomologen, Ornithologen, aber auch Lichttechniker fanden heraus, dass kunstliche Beleuchtung mitMaß und Ziel eingesetzt werden sollte - im Innen- wie im Außenraum. Das “Gluhlampenverbot” derEU ruckte Licht als bedeutenden Faktor im Energiekonsum in unser Bewusstsein (wenn auch aufungluckliche Weise!). Der Vortrag zeigt, dass und wie Beleuchtung nicht nach dem “Gießkannen-prinzip”, sondern bedarfsgerecht erfolgen sollte. Es wird auch darauf aufmerksam gemacht, dassEnergieeffizienz alleine nicht zu umfassend “besserem Licht” fuhrt. Grundlage der Ausfuhrungenist das Buch “Das Ende der Nacht – Die globale Lichtverschmutzung und ihre Folgen” von ThomasPosch, Anja Freyhoff, Thomas Uhlmann (Hg.) Wiley-VCH Verlag, Weinheim 2010.

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Tue, 11:45

Das kann Sonnenschutz: Energie, Licht und Warme - zumNulltarif!

Johann Gerstmann1

1Bundesverband Sonnenschutztechnik Osterreich, Guntramsdorf, Austria

Um solare Energie richtig nutzen zu konnen, muss die Kraft der Sonne je nach Tages- undJahreszeit sowie entsprechend bautechnischer Parameter wie Raumnutzung, Bauweise, Glasqualitat,Fensterflachen-anteil, Orientierung der Fassaden, bedarfsgerecht geregelt werden. So wie ein Ther-mostatventile die Heizung regelt, so sollte temporarer und intelligent gesteuerter Sonnenschutz denWarmeeintrag uber Fenster und Glasfassaden regeln. Im Gegensatz zur Notwendigkeit den En-ergieeintrag dem Außenklima anzupassen, gilt es diffuses Tageslicht maximal zu nutzen – fur einehohe Tageslichtautonomie im Sinne der Energieeffizienz aber vor allem in Hinblick darauf, dass dieWirkung von Tageslicht auf den Menschen durch Kunstlicht nicht ersetzt werden kann. Vor Sonneschutzen aber gleichzeitig Tageslicht nutzen muss kein Widerspruch sein, ist aber eine spannendeHerausforderung sowohl fur die Architektur als auch fur die Industrie! Sonnenschutz ist eine passiveTechnologie um thermischen und visuellen Komfort in Gebauden bei geringstem Energiebedarf zusichern. Neben Photovoltaik und Solarthermie ist die Sonnenschutztechnik - also das Managen desEnergie- und Lichteintrages uber transparente Flachen – die dritte aber inoffizielle Saule solarerEnergienutzung, die zum Erreichen der EU 20-20-20 Ziele noch eine große Rolle spielen kann.

Tue, 12:15

Leuchtdioden verandern unsere WeltGunther Leising1

1Technische Universitat Graz, Petersgasse 16/1.Sotck, 8010 Graz, Austria

Wir sehen mit unseren Augen Licht im Bereich von violett (400 nm) bis rot (750 nm). Da jederMensch ein individuelles Lichtempfinden hat, wurde fur den technischen Vergleich ein “Normauge”festgelegt, das bei 555 nm (grun) die maximale Sehempfindlichkeit hat. Damit wir alle Farben einesObjekts tatsachlich wahrnehmen konnen, muss die Lichtquelle mit der es beleuchtet wird, Lichtaller Farben im Bereich des Sichtbaren aussenden. Nur die Gluhbirne (und die Halogenlampe) hat-ten bisher annahernd diese Eigenschaft. LED sind kleine (typisch 0.3x0.3 mm), dunn-schichtweiseaufgebaute Festkorper-Lichtquellen die mit Spannungen einiger Volt betrieben werden. Mit einerblauen, grunen und roten LED oder mit einer blauen LED und neuartigen Farbstoffumhullungenkann praktisch Licht aller Farben und auch weißes Licht mit hoher Farbwiedergabequalitat erzeugtwerden. Wichtige Eigenschaften neben der Farbwiedergabe einer Lichtquelle sind die Effizienz (Lu-men/Watt) und die Farbtemperatur in Kelvin (K). Eine Gluhbirne hat eine Effizienz von 10 bis15 lm/W und je nach Betrieb Farbtemperaturen zwischen 2700K und 6500K. Die Effizienz einerHalogenlampe liegt bei 20 lm/Watt. Energiesparlampen und Leuchtstoffrohren haben typischer-weise um die 80 lm/W. Gute “weisse” LEDs liegen derzeit zwischen 70 und 100 Lumen/Watt unddas erreichbare Ziel fur LEDs liegt bei 200 Lumen/Watt. Die anvisierte Lebensdauer von LEDLichtquellen liegt weit uber 50.000 Stunden. Mit der LED Technologie erlebt die Lichttechnik unddamit die Beleuchtung eine langst fallige Erneuerung und Bereicherung.

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Tue, 12:45 - 13:30: Lunch

Tue, 13:30 - 16:00, HS 15.03

Tue, 13:30

“Oma Gluhbirne, Enkerl LED und der wilde OnkelScheinwerfer erzahlen”

Mistelbach HAK/HAS1

1HAK/HAS Mistelbach, Brennerweg 8, 2130 Mistelbach, Austria

Vorstellung und Diskussion (Film der HAK/HAS Mistelbach)

Tue, 13:50

LED – Die Lichtquelle der Zukunft revolutioniert auch dieAutomobilindustrie!

Dieter Parth1

1Infineon Technologies Austria AG, Application Specialist Power LED Drivers, Villach, Austria

Die Verwendung von LEDs ist heute einer der Designtrends im Automobilbereich, um denWiedererkennungswert unterschiedlicher Automarken zu steigern. Mittlerweile sind jedoch dieLeuchtstarken der LEDs so hoch, dass auch Auf- und Abblendlichter und damit komplette Voll-LED Scheinwerfer Losungen realisiert werden konnen. Der LED Trend beschrankt sich nicht nurauf die Fahrzeugaußenbeleuchtung. Im Fahrzeuginnenraum wird durch die Verwendung von RGBLEDs eine individuelle Anpassung der Innenbeleuchtung moglich. Aufgrund der kleinen Baugroße,der geringen Stoßempfindlichkeit sowie hohen Effizienzen werden vollig neuartige LED-Lichtdesignsmoglich. Die Lebensdauer von LEDs (50.000 Stunden) ist bei richtiger Handhabung um einVielfaches hoher als bei gewohnlichen Gluhlampen (1000 Stunden). Gerade bei Heckleuchten prof-itiert man vom schnellen Ansprechverhalten der LEDs, welche beim Anzeigen des Bremsvorgangeseinen Sicherheitsvorteil bieten. Intelligente Halbleiterlosungen zur Ansteuerungen von Gluh- oderHalogenlampen haben bereits lange Tradition beim Villacher Chiphersteller Infineon - er ist seitJahren Marktfuhrer auf diesem Gebiet. Die Infineon AUTO LED Familie beinhaltet Produkte zurAnsteuerung von LED Licht-Funktionen. Deren Hauptaufgaben sind die genaue Regelung des zurFunktion benotigten Laststromes, die Diagnose und der Schutz der Lasten vor Ubertemperaturund Boardnetzschwankungen. Dass sich der LED Trend auch im Automobil voll durchsetzt zeigenbereits zahllose Beispiele auf unseren Straßen. Laut Experten soll es im Jahr 2030 bereits keineGluhbirnen mehr im Auto geben. Infineon tragt maßgeblich zur Entwicklung und Markteinfuhrungvon LED-Beleuchtungslosungen im Automobil bei.

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Tue, 14:20

PHOTO-TEKTUR: Qualitativer Lichteintrag undphotobiologische Grundlagen fur ArchitektInnen

Gregor Radinger1

1Donau-Universitat Krems, Department fur Bauen und Umwelt, Dr.-Karl-Dorrek-Straße 30, 3500 Krems, Austria

Hintergrund: Beim Durchgang durch Verglasungen werden wesentliche Bereiche des solarenStrahlungs-spektrums ausgefiltert. Naturliches Licht, das derart spektral ausgedunnt den Innen-raum erreicht, ist aus humanphysiologischer Sicht reduziert oder gar nicht wirksam. Vor diesemHintergrund werden tatsachliche Gegebenheiten der Tageslichtversorgung in Innenraumen, mit Fo-cus auf den ultravioletten und sichtbaren Spektralbereich aufgezeigt.

Planungsrelevanz: Aufbauend auf diesen Erkenntnissen werden Empfehlungen fur photobiolo-gisch notwendige Eigenschaften von transparenten Bauteilen und gesundheitsforderlicher Raumkon-figurationen erstellt. Daruber hinaus wird die Bedeutung direkter und diffuser Lichteintrage aufdie qualitative Wahrnehmung von Raumen untersucht, um den wichtigen Stellenwert von Licht furdie allgemeine Akzeptanz von Architektur zu unterstreichen.

Vortragsthemen:

• Strahlungsangebot im Außenraum• Strahlungsangebot im Innenraum• Visuelle und nicht visuelle Lichtwahrnehmung• Qualitative Raumwahrnehmung bei diffusem und direktem Lichteintrag• Ableitungen fur architektonische Entwurfsstrategien

Tue, 14:50

Licht und Energie im GebaudeWilfried Pohl1

1Bartenbach LichtLabor GmbH, Aldrans, Austria

Im Vortrag wird die Rolle des Lichtes fur den Energiehaushalt eines Gebaudes erlautert. Dabeispielt nicht nur die elektrische Beleuchtung sondern insbesondere auch die Tagesbelichtung einewichtige Rolle. Es wird ein Uberblick und Ausblick uber energiesparende Beleuchtungstechnolo-gien gegeben und der Zusammenhang mit visuellem Komfort und dem Wohlbefinden erlautert.Die Richtlinie 2010/31/EU des europaischen Parlaments und des Rates vom 19. Mai 2010 uberdie Gesamtenergieeffizienz von Gebauden besagt, dass neue Gebaude ab 2021 als Niedrigsten-ergiegebaude errichtet werden sollen. In diesem Zusammenhang spielt der elektrische Energiever-brauch fur Beleuchtung eine zunehmend wichtigere Rolle. Der Vortragende ist als Prokurist beider Fa. Bartenbach LichtLabor in Aldrans fur Forschung zustandig. Er ist in zahlreiche inter-nationale Energieforschungsprojekte involviert, u.a. hat er im Auftrag des BMVIT Osterreich iminternationalen IEA- Projekt “Energy efficient electric Lighting for Buildings” vertreten und dieArbeitsgruppe “Zukunftige Lichttechnologien” geleitet (die Internationale Energieagentur IEA isteine zwischenstaatliche Einrichtung zur Forderung energiesparender Technologien und Aktivitaten),sowie im EU-Projekt “Commoncense” (Comfort monitoring for CEN standard EN15251 linked toEPBD) die osterreichische Beteiligung geleitet (ein Projekt der Intelligent Energy Europe, kurzIEE). Hier wird u.a. die Rolle der Beleuchtung (Kunst- und Tageslicht) fur den Energieverbrauchvon Gebauden untersucht.

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Tue, 15:20

Smart Lighting for Smart Citizens - Mehr Licht !? undinnovative Beleuchtungskonzepte fur Smart Cities.

Mathias Schaffer1

1Energie Steiermark, Graz, Austria

Die Energie Steiermark beschaftigt sich seit 2010 systematisch mit dem Thema “Innovation”bzw. Innovationsmanagement. Zielsetzung der Innovation ist dabei primar die Entwicklung neuerIdeen zu marktfahigen Produkten und Energie-Dienstleistungen im Kontext zum beginnendenWandel der Energiesysteme sowie des gesellschaftlichen Wertewandels. Neben der aktuellen, kun-denorientierten Entwicklung von innovativen Produkten und Dienstleistungen u.a. auch fur denBereich der Beleuchtung werden die Haupt-Innovationsthemen der Branche wie z.B. Smart Me-ter/Grid, dezentrale Erzeugung und Elektromobilitat als Teil großflachiger Modellversuche sog.“Smart Cities” demonstriert. Energie und deren Verwendung bzw. Anwendung unter Einsatzneuester und hocheffizienter Technologie ist auch in der ”Stadt der Zukunft” ein Schlusselthema– wie leben und arbeiten wir im Jahr 2050, welche Energieformen und Technologien stehen unszur Verfugung? Eine (mogliche) Projektion der “Vision 2050” einer “Smart City” fur das Thema“Licht”. . .

Tue, 15:50

SchlussworteNorbert Pillmayr1

1KELAG - Karntner Elektrizitats-Aktiengesellschaft, Klagenfurt, Austria

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34

4 Nuclear and Particle Physics (FAKT)Tue: HS 15.02; Thu, Fri: HS 15.03

Nuclear and Particle PhysicsKern- und TeilchenphysikDaniel Grumiller, [email protected]

Tuesday, 18th September 2012, HS 15.0213:30 - 16:00


13:30 - 13:50 Tobias JenkeGravity Resonance Spectroscopywithin the qBounce experiments

13:50 - 14:10 Johann Marton New experiments on light kaonic atoms

14:10 - 14:22 Barbara WunschekComparison of the yields in kaonichelium-3 and helium-4

14:22 - 14:34 Clemens SauerzopfMeasuring the hyperfine-splitting ofAntihydrogen

14:34 - 14:46 Martin DiermaierAn apparatus for the production of amono atomic hydrogen beam

14:46 - 14:58 Jenny FeigeAMS Measurements of Supernova-Produced Radionuclides in Deep-SeaSediment Cores

14:58 - 15:10 Edith SchmidtAMS detection of 10Be with a sili-con nitride foil stack: higher efficiency,lower background

15:10 - 15:22 Jakob Liebl

The age of olfactory bulb neurons inhumans: an application of dating mi-crogram DNA samples with the C14bomb peak

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Thursday, 20th September 2012, HS 15.0309:00 - 11:00


09:00 - 09:20 Wolfgang AdamRecent results from the CMS experi-ment at the LHC

09:20 - 09:32 Wolfgang WaltenbergerThe CMS simplified models results in-terpreted for your favorite theory – ahow-to

09:32 - 09:44 Robert SchofbeckSearch for Supersymmetry in finalstates with b-jets and leptons with theCMS experiment

09:44 - 09:56 Ilse KratschmerMeasurement of Upsilon(nS) Polariza-tion with CMS

09:56 - 10:08 Patrick JusselRecent Heavy Flavour Results at theATLAS Experiment at the LHC

10:08 - 10:20 Anna UsanovaSearch for rare Bs → µ + µ− decaywith the ATLAS detector

10:20 - 10:32 Wolfgang LukasMeasurement of charged-particle mul-tiplicities with the ATLAS detector atthe LHC

10:32 - 10:52 Christoph Schwanda Physics at the Belle II experiment

10:52 - 11:04 Felicitas ThorneStudy of B0s → J/ψK + K− decaysat Belle experiment




14:30 - 14:42 Stefan StrickerHolographic dilepton and prompt pho-ton production in a thermalizingplasma

14:42 - 14:54 Richard WilliamsStatus of the g-2 of the muon: trou-ble for the standard model or theoristsoverconfidence

14:54 - 15:06 Christian KohlfurstElectron-Positron Pair Production inStructured Pulses of Electric Fields

15:06 - 15:18 Markus HuberZwei- und Dreipunktfunktionen zwei-dimensionaler Yang-Mills-Theorie inLandau Eichung

15:18 - 15:30 Tina HerbstPolyakov-Loops and the QCD PhaseStructure


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15:50 - 16:02 Mario MitterConsequences of an Infrared DivergentQuark 4-Point Function

16:02 - 16:14 Valentin MaderRenormalization in Functional Ap-proaches

16:14 - 16:26 Andreas Windisch What is (not) a Glueball?

16:26 - 16:38 Markus HopferThe Role of the Quark-Gluon VertexFunction in the QCD Phase Transition

16:38 - 16:58 Reinhard AlkoferProperties of the Delta and OmegaBaryons from QCD Bound State Equa-tions

16:58 - 17:10 Matthias BlatnikThe sigma meson in a covariant Dyson-Schwinger - Bethe-Salpeter approach

17:10 - 17:22 Gernot EichmannNucleon Compton scattering in theDyson-Schwinger approach

17:22 - 17:34 Harold SteinackerMatrix Models as unified models offundamental interactions

Friday, 21st September 2012, HS 15.0309:00 - 11:00


09:00 - 09:12 Thomas WieningerProducing a new in-house C-14 stan-dard by irradiating graphite

09:12 - 09:24 Josef BuchrieglerA multi-anode ionisation chamber forAMS at VERA

09:24 - 09:44 Gertrud Konrad Status Report on PERC

09:44 - 09:56 Christoph GosselsbergerEin Neutronenspinresonator zurErzeugung Wellenlangen-selektierterNeutronenpulse

09:56 - 10:08 Xiangzun Wang Magnetic Field System of PERC

10:08 - 10:20 Florian TeischingerCalibration of the ATLAS electromag-netic calorimeter at the per mill level

10:20 - 10:32 Elmar RitschThe Integrated Simulation Framework– A novel Detector Simulation Ap-proach in the ATLAS Experiment

10:32 - 10:44 Bernhard LutzerRadiation-hard silicon sensors for theCMS tracker upgrade

10:44 - 10:56 Edwin FruhwirthDevelopment and Production of Sili-con Particle Detectors in Austria


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11:30 - 11:42 Wolfgang Treberer-TreberspurgMonitoring of the radiation induced ef-fects of the CMS Tracker

11:42 - 11:54 Immanuel GfallBelle II Silicon Vertex Detector: Me-chanics

11:54 - 12:06 Annekathrin FrankenbergerBelle II Silicon Vertex Detector: Cool-ing

12:06 - 12:18 Jakob LettenbichlerLow-momentum track reconstructionin the vertex detector of Belle II

12:18 - 12:30 Winfried MitaroffForward Tracking in a Linear ColliderDetector

12:30 - 12:42 Sebastian FrankComputational Uncertainties in PublicBR(B → Xsγ) Codes

12:42 - 12:54 Lukas GruberRecovery Time and Double Hit Reso-lution Measurements of SiPMs Using aDouble Pulsed Laser

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Tue, 13:30 - 16:00, HS 15.02

Tue, 13:30

Gravity Resonance Spectroscopy within the qBounceexperiments

Tobias Jenke1

1Technische Universitat Wien, Stadionallee 2, 1020 Wien, Austria

Newton’s Inverse Square Law of Gravity may be tested at micron distances deeply into thetheoretically interesting regime by quantum interference with ultra-cold neutrons. Our newly de-veloped method is based on a resonance spectroscopy technique related to Rabi spectroscopy, whichhas been adapted to gravitationally bound quantum systems: By coupling such a quantum systemto mechanical vibrations, we observe resonant transitions, devoid of electromagnetic interaction.As Newtonian gravity and hypothetical Fifth Forces evolve with different phase information, theexperiment has the potential to test the equivalence principle and Newton’s gravity law at themicron scale. This experiment can therefore test speculations on large extra dimensions of sub-millimetre size of space-time or the origin of the cosmological constant in the universe, where effectsare predicted in the interesting range of this experiment and might give a signal in an improvedsetup.

Tue, 13:50

New experiments on light kaonic atomsJohann Marton1, The LEANNIS network2, The SIDDHARTA Collaboration3

1Osterreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria2http://www.oeaw.ac.at/smi/research/topics/strong-interaction/leannis/

3http://www.lnf.infn.it/esperimenti/siddharta/

The antikaon interaction on nucleons and nuclei in the low-energy regime is neither simple norwell understood. Even the kaonic hydrogen and kaonic deuterium cases are complicated due tosub-threshold resonances – most prominent is the Lambda(1405) resonance of still heavily debatednature. New experimental studies via x-ray spectroscopy of the lightest kaonic atomic systems(kaonic hydrogen and helium isotopes) have successfully performed by the SIDDHARTA Collabo-ration at LNF (Frascati, Italy) recently. Consequently new precision data on the strong interactionobservables were delivered giving important impact for the theory. The talk will give an overviewof the progress and present status of experimental studies and will provide an outlook to futureperspectives in this fascinating research field.

39

Tue, 14:10

Comparison of the yields in kaonic helium-3 and helium-4Barbara Wunschek1, Tomoichi Ishiwatari1, Eberhard Widmann1, Johann Zmeskal1,

Michael Cargnelli1, Johann Marton1

1Osterreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria

Kaonic helium is an exotic atom where a kaon replaces a shell electron, well suited for thestudy of the strong interaction at low energies. The strong interaction between the kaon and thenucleus affects the low-lying atomic states in the kaonic helium atom by causing a shift comparedto its purely electromagnetic value. This shift can be measured with spectroscopic tools, which wasrecently performed by the SIDDHARTA experiment. Via a measurement of the X-ray transitionsto the 2p level, the X-ray transitions in kaonic helium-3 and helium-4 (at different densities) weremeasured with a complex SDD detector system. With the data set of these measurements, theX-ray yields (i.e. the net production of characteristic X-rays) of the kaonic helium gases have beendetermined for the first time. The absolute yields were obtained with inputs from a Monte Carlosimulation. Since the previous measurements on the kaonic helium X-ray transitions solely usedliquid helium targets, these results give crucial information on theoretical calculations of the den-sitydependence of the yields. The evaluation procedure and the results are going to be presentedin detail.

Tue, 14:22

Measuring the hyperfine-splitting of AntihydrogenClemens Sauerzopf1, Martin Diermaier1, Silke Federmann1, Chloe Malbrunot1, Oswald Massiczek1,

Barbara Wunschek1, Johann Zmeskal1, Eberhard Widmann1, The ASACUSA Collaboration2

1Osterreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria2http://asacusa.web.cern.ch/ASACUSA/

In our current understanding of the standard model of particle physics, the CPT (charge, par-ity, time) symmetry states that the laws of physics do not change under inversion. The ASACUSACollaboration intends to test this fundamental property of the model by measuring a hyperfinetransition in Antihydrogen, the antimatter pendant to ordinary matter Hydrogen, using a Rabilike experimental setup. Compared to the number of cosmic particles and background radiationfrom Antiproton annihilation a proper Antihydrogen event is quite rare. To accomplish a goodmeasurement we need a fine discrimination between proper events and background hits. To thispurpose, our counting system consists of a veto detector to single out upstream annihilations, acentral segmented detector, and a hodoscope which provides a good detection probability for decaypions. In this talk I will discuss the development of the Antihydrogen counter and present firstpreliminary results of measurements at the CERN Antiproton Decelerator (AD).

40

Tue, 14:34

An apparatus for the production of a mono atomic hydrogenbeam

Martin Diermaier1, Oswald Massiczek1, Eberhard Widmann1, Johann Zmeskal1

1Osterreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria

CPT (charge, parity, time) symmetry plays a fundamental role in our understanding of physicallaws – under the simultaneous inversion of charge, parity and time the physics law do not change.The CPT symmetry will be tested by the ASACUSA collaboration at the CERN facility. This testwill be done in a Rabi like experiment with antihydrogen atoms, the antimatter pendant to normalhydrogen atoms. Since the creation of antihydrogen atoms is very complicated the whole setuphas to be tested and calibrated with hydrogen. Therefore an atomic hydrogen beam apparatushas been setup, using a microwave discharge source for the production and a quadrupole massspectrometer for the detection of the mono atomic hydrogen beam. In this talk the apparatus andfirst test measurements will be discussed.

Tue, 14:46

AMS Measurements of Supernova-Produced Radionuclides inDeep-Sea Sediment Cores

Jenny Feige1, Anton Wallner2, Stephan Winkler1, Silke Merchel3, Keith Fifield2,

Gunther Korschinek4, Georg Rugel3, Robin Golser1

1University of Vienna, Wahringer Strasse 17, 1090 Vienna, Austria2Australian National University,Building No. 57, The Australian National University, Canberra, ACT 0200, Australia

3Helmholtz Institute Freiberg for Resource Technology, Halsbrucker Straße 34, 09599 Freiberg, Germany4Technische Universitat Munchen, James-Franck-Str. 1, 85748 Garching, Germany

Accelerator Mass Spectrometry (AMS) provides the highest sensitivity for measurements oflong-lived radionuclides with half-lifes in the order of million years. We apply this method tosearch for live supernova (SN)-produced radionuclides on Earth. An indication to recent SN activ-ity in our solar neighborhood is the existence of a thin, hot cavity in the local interstellar medium,embedding our solar system. This so called superbubble, the Local Bubble, was produced by mul-tiple SN explosions, starting ∼14 Myr ago. Nuclides, which are synthesized in massive stars andduring their explosions, are then entrained in the SN shell and may be transported to the solar sys-tem and thus into Earth archives, if such an event happens within a short distance. Two deep-seasediment cores originating from the Indian Ocean have been selected to search for the SN-producedradionuclides 26Al, 53Mn, 60Fe and 244Pu in the time range of 2-3 Myr. We aim to measure theseisotopes at different laboratories with high time resolution with the goal to confirm a previouslyfound SN signal in a ferromanganese crust from the Pacific Ocean.

41

Tue, 14:58

AMS detection of 10Be with a silicon nitride foil stack:higher efficiency, lower background

Edith Schmidt1, Peter Steier1, Josef Buchriegler1, Jenny Feige1, Martin Martschini1,Leonard Michlmayer1, Alfred Priller1, Anton Wallner1, Eva-Maria Wild1, Robin Golser1

1University of Vienna, Wahringer Strasse 17, 1090 Vienna, Austria

10Be, with a half-life of 1.39 Ma, is a long-lived, naturally occurring radioisotope with versatileapplications. It is a cosmogenic nuclide, produced in the atmosphere and in-situ in surface rocks.10Be therefore carries valuable signals for climate research [1,2] and also is the primary tool forexposure dating [3] in geology. Accelerator Mass Spectrometry (AMS) with its outstanding abun-dance sensitivity is the only technique capable of measuring 10Be at natural levels and separatingit from abundant isobaric 10B. Based on extremely homogeneous silicon nitride foils, we have de-veloped a new AMS-method to detect 10Be at the Vienna Environmental Research Accelerator(VERA). The new method has a significantly higher overall efficiency, provides superior precisionand is simpler to implement. For comparison, we also present the two other methods, which areavailable at VERA and commonly used at other facilities: absorption of 10B in a gas cell, and theuse of a degrader foil followed by a magnetic separator.

[1] RAISBECK et. al. (2006) 10Be evidence for the Matuyama-Brunhes geomagnetic reversal inthe EPICA Dome C ice core. Nature 444, 82.[2] WILLENBRING, J.K., VON BLANCKENBURG, F. (2010) Long-term stability of global ero-sion rates and weathering during late-Cenozoic cooling. Nature 465, 211.[3] JOHN, C., GOSSE, F., PHILLIPS, M.(2001) Terrestrial in situ cosmogenic nuclides: theoryand application. Quaternary Science Reviews 20, 1475.

Tue, 15:10

The age of olfactory bulb neurons in humans: an applicationof dating microgram DNA samples with the C14 bomb peakJakob Liebl1,2,3, Peter Steier1, Olaf Bergmann4, Jonas Frisen4, Kirsty Spalding4, Robin Golser1,

Klaus Mair1, Alfred Priller1, Eva-Maria Wild1, Walter Kutschera1

1University of Vienna, Wahringer Strasse 17, 1090 Vienna, Austria2MedAustron, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria

3Medizinische Universitat Graz, Auenbruggerplatz 32, 8036 Graz, Austria4Karolinska Institutet, SE-171 77 Stockholm, Sweden

The determination of C14 levels in genomic DNA can be used to retrospectively establish thebirth date of cells in the human body which was pioneered at the Karolinska Institute. Above-ground nuclear weapons testing between 1950 and 1963 doubled the atmospheric C14 content.After the Partial Nuclear Test Ban Treaty in 1963 the excess C14 decreased again by exchange ofcarbon dioxide between atmosphere, biosphere and the ocean. As a consequence all humans wholived in the second half of the 20th century have been labelled with this rapidly changing excessC14. During the last years the amount of carbon required for a C14 Accelerator Mass Spectrometry(AMS) measurement at the VERA Laboratory in Vienna was reduced to such an extent (mg to µg)that investigations of neurons of particularly interesting small sections of the human brain becamepossible. C14 measurements of < 5µg carbon DNA samples with an overall precision of 2.0 to 2.5%were achieved. This allowed to study neurogenesis in the human olfactory bulb [1], which turnedout to take place primarily at birth with <1% of these neurons being exchanged at a later time.This identifies a fundamental difference in the plasticity of the human brain compared to othermammals.

[1] O. Bergmann, J. Liebl, S. Bernard, K. Alkass, M.S.Y. Yeung, P. Steier, W. Kutschera, L.Johnson, M. Landen, H. Druid, K.L. Spalding, J. Frisen, “The Age of Olfactory Bulb Neurons inHumans”, Neuron 74, 634 (2012)

42

Thu, 09:00 - 11:00, HS 15.03

Thu, 09:00

Recent results from the CMS experiment at the LHCWolfgang Adam1

1Institut fur Hochenergiephysik, Nikolsdorfer Gasse 18, 1050 Wien, Austria

The CMS experiment is in its third full year of data taking at the LHC, recording proton-protoncollisions at a record centre-of-mass energy of 8 TeV. The total integrated luminosity is expectedto clearly exceed the 5 fb−1 available for the analysis of 2011 data. CMS pursues a wide researchprogramme with highlights ranging from the search for the Higgs boson and supersymmetric par-ticles to precision measurements in top- and b-quark physics. An overview of the most significantCMS results with emphasis on those obtained from the first part of 2012 data will be presented.

Thu, 09:20

The CMS simplified models results interpreted for yourfavorite theory – a how-to

Wolfgang Waltenberger1

1Institut fur Hochenergiephysik, Nikolsdorfer Gasse 18, 1050 Wien, Austria

The year 2011 was a fruitful one for the CMS teams that searched for physics beyond the stan-dard model. The results of many analyses have been interpreted in the context of simplified models,i.e. effective Lagrangians which introduce only a minimal set of hypothetical, new particles. In thistalk, a description and summary of these simplified models results will be given. An applicationof these results that can be performed by physicists outside the CMS collaboration will be presented.

Thu, 09:32

Search for Supersymmetry in final states with b-jets andleptons with the CMS experiment

Robert Schofbeck1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

A large class of supersymmetric models predict an enhanced production of 3rd generationfermions at the LHC. In particular, the supersymmetric partners of bottom and top quarks couldbe among the lightest charged supersymmetric particles and would give rise to jets originating fromthe fragmentation of b-quarks. Results from searches for Supersymmetry with the CMS experi-ment using final states including with b-jets are reported based on proton-proton collision dataat a centre-of-mass energy of 7 TeV and 8TeV. In particular, a searches for events with (b-)jets,isolated leptons and high missing transverse energy are presented. The results are also interpretedin the framework of “simplified models”.

43

Thu, 09:44

Measurement of Upsilon(nS) Polarization with CMSIlse Kratschmer1


An introduction to the measurements of quarkonia polarization with the CMS detector at theLHC is presented. The measurement is based on the angular distributions of decays into muons.The polarization parameters λθ, λφ and λθφ as well as a frame invariant quantity λ are determined.This frame-invariant quantity provides an intrinsic test of the reliability of the whole analysis chainand gives supplementary physical information. Results for the Y(1S), Y(2S) and Y(3S) mesonsusing data collected in 2012 are shown.

Thu, 09:56

Recent Heavy Flavour Results at the ATLAS Experiment atthe LHCPatrick Jussel1

1University of Innsbruck, Technikerstrasse 15, 6020 Innsbruck , Austria

In 2011 data corresponding to an integrated luminosity of more than 5 fb−1 has been collectedby the ATLAS experiment [1] at the Large Hadron Collider at CERN. The heavy flavour programcovers the measurement of CP violation, the discovery of new B hadrons and very rare B mesondecays. In this presentation recent results of the ATLAS heavy flavour physics program will bepresented.

[1] The ATLAS Collaboration; The ATLAS Experiment at the CERN Large Hadron Collider;JINST 3 (2008) S08003

Thu, 10:08

Search for rare Bs→ µ+ µ− decay with the ATLAS detectorAnna Usanova1

1University of Innsbruck, Technikerstraße 15, 6020 Innsbruck , Austria

A blind analysis searching for the decay Bs → µ + µ− has been performed [1] using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at theLHC in 2011. The Bs→ µ+µ− branching fraction is measured with respect to the reference decayB± → J/ψK±. The details of this analysis and the most recent results on the measurement of thebranching fraction BR(Bs→ µ+ µ−) will be presented.

[1] The ATLAS Collaboration; Search for the decay B0s → µ + µ− with the ATLAS detector; tobe published

44

Thu, 10:20

Measurement of charged-particle multiplicities with theATLAS detector at the LHC

Wolfgang Lukas1, Emmerich Kneringer1, Andreas Salzburger2

1University of Innsbruck, Technikerstraße 15, 6020 Innsbruck , Austria2CERN, 1211 Geneva 23, Switzerland

Measurements of charged-particle distributions in particle collider experiments provide an es-sential insight into the understanding of soft QCD as well as high-pT phenomena, which are be-coming increasingly important for high-energy physics at the LHC. The status of ongoing mea-surements of the charged-particle multiplicity in proton-proton interactions at the center-of-massenergy

√s = 8 TeV, depending on transverse momentum and pseudorapidity, and of the relation-

ship between mean transverse momentum and charged-particle multiplicity, is presented for theATLAS experiment. These measurements are compared to Monte Carlo models, particularly thePythia6 and Pythia8 tunes. Finally the 8 TeV results are combined with previous measurementsfrom 900 GeV to 7 TeV, in order to validate and improve the extrapolation of the central charged-particle multiplicity per event and unit of pseudorapidity for tracks with transverse momentum pT> 100 MeV and pT > 500 MeV.

Thu, 10:32

Physics at the Belle II experimentChristoph Schwanda1


The B factory at KEK in Japan is being upgraded to become a Super B factory: The newexperiment, Belle II, will start data taking in the year 2015 and aims at increasing the B factorydataset by two orders of magnitude. This huge luminosity will allow to study B and tau decayswith unprecedented precision and gain sensitivity to physics scenarios beyond the Standard Modelof particle physics (so-called New Physics). We will present the planned measurements and giveexpected sensitivities in key observables. We will explain how different New Physics models can beprobed with the upgraded detector.

Thu, 10:52

Study of B0s→ J/ψK +K− decays at Belle experimentFelicitas Thorne1, Christoph Schwanda1


The Belle experiment in Tsukuba (Japan) has collected a unique 121/fb dataset near the Y(5S)resonance, which allows to study B0s meson decays. We will report a study of B0s→ J/ψK+K−decays using this sample. This includes the measurement of the absolute branching fractionsfor B0s → J/ψφ with φ → K + K− and B0s → J/ψK + K−, the search for the decayB0s → J/ψf ′2(1525) with f ′2(1525) → K + K− and the determination of the s-wave contri-bution in the φ mass range. The decay B0s→ J/ψφ is an important mode for measuring the CPviolating phase βs, which is particularly sensitive to physics beyond the Standard Model. Thiswork is supported by the Austrian Science Fund (Grant Nr. P22742-N16).

45

Thu, 14:30 - 15:30, HS 15.03

Thu, 14:30

Holographic dilepton and prompt photon production in athermalizing plasma

Stefan Stricker1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria

We determine the out-of-equilibrium production rate of dileptons and prompt photons instrongly coupled N=4 Super Yang-Mills plasma using the AdS/CFT correspondence. Thermal-ization is achieved via the gravitational collapse of a thin shell of matter in anti-de-Sitter spacetimeand the subsequent formation of a black hole, which we describe in a quasistatic approximation.Prior to thermalization, the spectral functions of dileptons and photons are observed to oscillateas a function of frequency, but the amplitudes of oscillations decrease when thermal equilibrium isapproached.

Thu, 14:42

Status of the g-2 of the muon: trouble for the standardmodel or theorists’ overconfidenceRichard Williams1, Christian Fischer2, Tobias Gocke2

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Universitat Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

A several year old discrepancy at the 2-3 sigma level between precision Standard Model com-putations of the muon’s magnetic moment and experimental measurement defies theory. I quicklyreview the last measurements, the various contributions to the theory estimate that include a mind-boggling 5-loop QED calculation as well as high-order QCD and electroweak corrections, and con-centrate especially on the hadronic contributions I will show how progress in the Dyson-Schwingerformulation of Chromodynamics provides a cross-check, extension and improvement over futurelattice and existing quark model and effective Lagrangian estimates, highlighting the strengths andweaknesses of the various approaches.

Thu, 14:54

Electron-Positron Pair Production in Structured Pulses ofElectric Fields

Christian Kohlfurst1, Florian Hebenstreit1, Reinhard Alkofer1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria

The non-perturbative electron-positron pair production (Schwinger effect) in time-dependentpulse-shaped electric fields is investigated. For pulses of experimental interest the employed quan-tum kinetic formalism reduces the equation for the electron (positron) density to a set of ordinarycoupled differential equations of first order. The dynamical effect of electric fields with at least twodifferent time scales within the pulse is studied. First results for an optimization of the particledensity yield by pulse-shaping will be given.

46

Thu, 15:06

Zwei- und Dreipunktfunktionen zwei-dimensionalerYang-Mills-Theorie in Landau Eichung

Markus Huber1, Axel Maas2, Lorenz von Smekal1

1Technische Universitat Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt, Germany2Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany

Gittersimulationen und nicht-perturbative Kontinuumsmethoden wie die funktionale Renor-mierungsgruppe und Dyson-Schwinger-Gleichungen haben unterschiedliche Starken und Schwachenund erganzen einander sehr gut. Da auf dem Gitter niedrige Impulse in zwei und drei Dimen-sionen leichter als in vier Dimensionen erreicht werden konnen, werden Rechnungen auch damitdurchgefuhrt. Dabei stellte sich heraus, dass das Verhalten in zwei Dimensionen qualitativ andersist als in drei und vier Dimensionen. Hier prasentieren wir analytische und numerische Ergebnissevon Dyson-Schwinger-Gleichungen, die diesen Unterschied erklaren. Eines der Hauptergebnisse istdie Sensibilitat der Ergebnisse auf den Bereich mittlerer Impulse, auf welchen Trunkierungen denmeisten Einfluss haben. Um die Trunkierungsabhangigkeit zu verkleinern, losen wir die Propagator-Gleichungen gemeinsam mit der Dyson-Schwinger-Gleichung des Geist-Gluon-Vertex.

Thu, 15:18

Polyakov-Loops and the QCD Phase StructureTina K. Herbst1, Bernd-Jochen Schaefer1, Jan Martin Pawlowski2

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Universitat Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany

We discuss the impact of fluctuations on the chiral and deconfinement phase transition of QCDwithin an effective model. Thermal and quantum fluctuations are included via the functional renor-malisation group. Special emphasis is put on the matter backcoupling to the gauge sector, whichhas a drastic influence on the phase structure.

Thu, 15:30 - 15:50: Coffee break

47

Thu, 15:50 - 18:00, HS 15.03

Thu, 15:50

Consequences of an Infrared Divergent Quark 4-PointFunction

Mario Mitter1, Reinhard Alkofer1


Based on the idea that a confining linear rising quark potential can be explained by a 1/k4

divergence in the quark 4-point function, we find restrictions on the color tensor structure of thisdivergence. Furthermore, we investigate consequences on other Green functions.

Thu, 16:02

Renormalization in Functional ApproachesValentin Mader1, Reinhard Alkofer1


In Functional Approaches, correlation functions are calculated self-consistently. Back-couplingeffects lead to drastic modification in the renormalization program in quantum field theories. Usingthe Dyson-Schwinger equations of Yang-Mills theory we investigate the influence of quadratic andlogarithmic divergences on the solution process of such equations.

Thu, 16:14

What is (not) a Glueball?Andreas Windisch1, Markus Huber2, Reinhard Alkofer1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Technische Universitat Darmstadt, Schlossgartenstrasse 9, 64289 Darmstadt, Germany

We present a short review on what glueballs are and how they can be described theoretically.In particular we discuss a scalar glueball, which is described by the two-point function of the squareof the Yang-Mills field strength tensor. The momentum-space operator corresponding to this cor-relator has been constructed such that dierent gluon-propagators in 2 and 4 dimensions can beplugged into the expression. While the gluon-propagators have been taken from non-perturbativestudies, the correlator itself is of lowest order in the coupling. By analytic continuation we extendthe solution to complex values of p2, the square of the external momentum. The structure ofthe correlator in the complex plane encodes important information of the propagating degree offreedom, such as its mass or whether it is a bound state or not. We perform this investigation nu-merically by applying a specifically developed procedure which involves Graphics Processing Unitsto carry out this computationally intensive task [1]. This tool allows us to investigate a varietyof gluon propagators of dierent origin, without having to deal with the limitations present due totheir complicated integral representations. The aim of this talk is to present not only the procedureused throughout the study, but also to stress what is not sufficient to get a glueball, restricting theingredients of this highly interesting, experimentally hard-to-prove objects.

[1] A. Windisch, R. Alkofer, G. Haase and M. Liebmann, arXiv:1205.0752 [hep-ph].

48

Thu, 16:26

The Role of the Quark-Gluon Vertex Function in the QCDPhase Transition

Markus Hopfer1, Mario Mitter1, Bernd-Jochen Schaefer1, Reinhard Alkofer1


During the last years, intensive theoretical and experimental efforts towards a deeper under-standing of the strong interactions between quarks and gluons, the fundamental fields in nature,have been made. In particular, the observed phenomena of confinement and dynamical mass gen-eration were at the focus of many contemporary studies. Up to now, the emergence of thesephenomena from the underlying fundamental theory, quantum chromodynamics (QCD), is not un-derstood in detail. Moreover, the transition from the confined hadronic phase to the quark-gluonplasma phase induces a sudden change in the particle masses indicating a relation between thesephenomena. As confinement and chiral symmetry breaking are intrinsic properties of the stronginteraction in the infrared, they are not accessible by perturbation theory. By relating the Greensfunctions of the theory, the Dyson-Schwinger formalism offers a non-perturbative description of thedynamics including quantum fluctuations which are mandatory in the vicinity of phase transitions.The quark-gluon vertex is the central object in this context linking the quark with the Yang-Millssector of the theory. Due to its complexity only models for this vertex are used up to now. Themajor focus is to replace these models by a detailed numerical investigation, including the relevanttensor structure and probing subsequently the phase diagram of QCD.

Thu, 16:38

Properties of the Delta and Omega Baryons from QCDBound State Equations

Reinhard Alkofer1, Helios Sanchis-Alepuz1, Richard Williams1


Based on rainbow-ladder truncated QCD bound state equations properties of the quark coreof mesons and baryons are calculated from their respective Bethe-Salpeter and Poincare-covariantFaddeev amplitudes. Results on the spectrum and electromagnetic form factors of Delta/Omegabaryons from light to heavy quarks are presented. To evaluate their dependence on the rainbow-ladder truncated, effective interaction calculations employing two different models have been per-formed.

Thu, 16:58

The sigma meson in a covariant Dyson-Schwinger -Bethe-Salpeter approach

Matthias Blatnik1, Reinhard Alkofer1, Richard Williams1


We study the f(600) or σ, the lowest scalar meson resonance, in the framework of a Dyson-Schwinger - Bethe-Salpeter approach which is based on the non-pertubative Green’s functions ofQCD. The σ has exactly the same quantum numbers as the vacuum, and it plays an important rolein dynamical chiral symmetry breaking and in nuclear physics. We investigate the σ starting witha qq state and aim in particular to include the decay into and coupling to two pions. We will giveresults for the bare, i.e., qq masses of the σ and the π and estimates for the σ mass and decay width.

49

Thu, 17:10

Nucleon Compton scattering in the Dyson-Schwingerapproach

Gernot Eichmann1


Compton scattering on the nucleon provides a unique tool to probe the nonperturbative struc-ture of the nucleon. It allows access to a range of observables that are subject to studies at majorexperimental facilities, including: the nucleon’s generalized polarizabilities; two-photon contribu-tions to form factors; nucleon structure functions and generalized parton distributions; and proton-antiproton annihilation processes. A nonperturbative approach for investigating such phenomenais given by the combination of QCD’s Dyson-Schwinger equations with covariant Bethe-Salpeterand Faddeev equations. The framework has been recently applied for describing nucleon and deltaelastic and transition form factors, and its systematic extension to Compton scattering, pion elec-troproduction and nucleon-pion scattering has been outlined. I will discuss recent progress in thisarea and present first results for the nucleon’s Compton scattering amplitude.

Thu, 17:22

Matrix Models as unified models of fundamental interactionsHarold Steinacker1

1University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria

Matrix models have been proposed as a non-perturbative definition of string theory. Basicsolutions and mechanisms are discussed for the so-called IKKT model. Space-time can arise asbrane solution, while gauge fields arise from fluctuations around stacks of branes. This leads to abraneworld scenario, with many parallels but also differences to more conventional string theoryconstructions. A overview of recent progress and an outlook is given.

50

Fri, 09:00 - 11:00, HS 15.03

Fri, 09:00

Producing a new in-house C-14 standard by irradiatinggraphite

Thomas Wieninger1, Klaus Mair1, Johannes Sterba2, Peter Steier1, Robin Golser1

1University of Vienna, Wahringer Strasse 17, 1090 Vienna, Austria2Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

Accelerator mass spectrometry (AMS) always performs measurements relative to a standard,which significantly improves the precision. C-14 measurements need a chemical treatment to trans-form carbon into graphite, to be used in the popular Cs-sputter sources. A homogeneous bulk ofseveral gram of graphite containing C-14 would allow to study the performance of the mass spec-trometer independent of sample preparation chemistry. Unfortunately, this material is not availableso far. The aim was to produce such a new in-house standard for the VERA facility (Universityof Vienna). We started from dead (p.e. no C-14) graphite powder and irradiated it with thermalneutrons at the TRIGA Mark II reactor from the Institute of Atomic and Subatomic Physics (TUVienna). Via the C-13(n, gamma)C-14 reaction we produced a C-14 isotopic abundance in thenatural range of ∼ 10−12. The challenge of this work was to deal with an inhomogeneous neu-tron flux and the low cross section for the mentioned above reaction, compared to the much moreefficient N-14(n,p)C-14. The homogeneity of the produced material was successfully verified bymeasurements of small aliquots.

Fri, 09:12

A multi-anode ionisation chamber for AMS at VERAJosef Buchriegler1, Alfred Priller1, Oliver Forstner1, Martin Martschini1, Peter Steier1,

Robin Golser1

1University of Vienna, Wahringer Strasse 17, 1090 Vienna, Austria

AMS (Accelerator Mass Spectrometry) is a technique to measure long-lived radionuclides withextreme abundance sensitivity below 1E-12. For sufficient isobar suppression at low energies (<1MeV/amu) a high-resolution detector is required. Based on recent experimental results for theseparation of 36Cl from 36S, a new gas ionisation chamber with a multi-anode design was builtat VERA (Vienna Environmental Research Accelerator). It provides up to 8 energy loss signalsfor particle identification. In order to reduce electronic noise special low-capacitive conductors areused inside the gas volume; also the preamplifiers are mounted directly on the detector housing.The dimensions of the Frisch grid [1] and the distances between grid and electrodes were optimizedboth for short pulse rise times as well as minimum grid-inefficiency [2]. The flexibility of the designconcerning the type of detector window, the configuration of anodes and the distances between gridand electrodes makes the detector also well suited for the measurement of heavy ions, e.g. 236Uat low energies. Calculations and first experimental results of the detector’s performance will bepresented.

[1] Bunemann O., Cranshaw T. E., Harvey J. A., “Design of Grid Ionization Chambers”, CanadianJournal of Research 27A (1949) 191-206[2] Gook A., “Investigation of the Frisch-grid inefficiency by means of wave-form digitization”, Dis-sertation, Orebro Universitet

51

Fri, 09:24

Status Report on PERCGertrud Konrad1, The PERC Collaboration2

1Technische Universitat Wien, Stadionallee 2, 1020 Wien, Austria2http://www.physi.uni-heidelberg.de/Forschung/ANP/PERC/collaboration.php

Important open questions of particle physics and cosmology can be addressed with precisionmeasurements in neutron beta decay. Main emphasis lies on the search for evidence of possibleextensions to the Standard Model and searches for new symmetry concepts. In general, these mea-surements are complementary to direct searches in high-energy physics. Observables in neutrondecay are abundant: Besides the neutron lifetime, angular correlations involving the neutron spinas well as momenta and spins of the emitted particles are characterized by individual coefficients.These coefficients can be related to the underlying coupling strengths of the weak interaction, in-cluding yet unobserved ones. Each coefficient in turn relates to an underlying broken symmetry.With the new facility PERC several symmetry tests based on neutron decay data become acces-sible. PERC (Proton Electron Radiation Channel) is a novel source of neutron decay products:these are collected by a strong longitudinal magnetic field of 1.5 T directly from inside a neutronguide. This combination provides highest phase space density of decay products. A magnetic mir-ror of up to 6 T serves to perform precise cuts in phase space, reducing related systematic errors.Altogether, the sensitivity of neutron decay studies will be improved by one order of magnitude.The new beam station PERC is currently under development by an international collaboration andwill be installed at the FRM II in Garching, Germany. Besides the physics motivation, the concept,sensitivity, applications, and status of PERC are presented in this talk.

Fri, 09:44

Ein Neutronenspinresonator zur ErzeugungWellenlangen-selektierter Neutronenpulse

Christoph Gosselsberger1, Gerald Badurek1, Erwin Jericha1

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

Im Rahmen dieses Beitrags stellen wir die erstmalige Entwicklung eines Wanderwellen-Neutronen-spinresonators zur Erzeugung nahezu beliebig geformter wellenlangenselektierter, polarisierter Neu-tronenpulse vor. Das Grundprinzip dafur ist die raumliche magnetische Spinresonanz. Dabeiwerden die polarisierten Neutronen einem raumlich abwechselnden magnetischen Feld ausgesetzt,welches normal zur Polarisationsrichtung angelegt ist. Die Frequenz dieses alternierenden Mag-netfeldes ist im Bezugssystem eines einzelnen Neutrons jeweils von dessen Geschwindigkeit undder raumlichen Periode des Resonators abhangig. Sofern diese Frequenz mit der Larmorfrequenzder Neutronen ubereinstimmt, welche durch das orthogonal angelegte statische Fuhrungsfeld (Se-lektorfeld) bestimmt wird, findet ein Pi-Spinflip statt. Durch eine geeignete Justierung diesesSelektorfeldes kann somit eine bestimmte Wellenlange selektiert werden. Bei der Neuentwick-lung wird ein sogenannter Wanderwellenmodus realisiert, bei dem ein “wanderndes” Magnetfeld,die zu erzeugenden Neutronenpulse durch den Resonator begleitet. Bei dieser Umsetzung er-scheinen um 2 Großenordnungen kurzere Pulszeiten als bei einem traditionellen Resonator re-alisierbar. Der Aufbau aus Einzelelementen hat den wesentlichen Vorteil, dass die erzeugtenMagnetfelder beliebig geformt und somit fur den Betrieb ungewollte Nebenmaxima in den selek-tierten Wellenlangenspektren eliminiert werden konnen. Außerdem konnen durch bloßes Einstellender Strome sowohl die Wellenlangenverteilung als auch die Zeitstruktur nahezu beliebig justiertwerden. Wir stellen hier sowohl die Designstudie als auch erste recht vielversprechende Mess-Resultate zweier Resonator-Prototypen vor und gehen auf mogliche zukunftige Anwendungen ein(Strahlpraparation bei PERC, neuartiges 3-Achsen-Spektrometer, Erzeugung von maßgeschnei-derten Neutronenpulsen an der ESS).

52

Fri, 09:56

Magnetic Field System of PERCXiangzun Wang1


The beam station PERC (Proton Electron Radiation Channel) is a new kind of spectrometerfor neutron beta decay experiments, aiming to achieve precise measurements of energy spectra ofelectrons and protons (e-/p+) from free neutron decay, as well as various angular correlation coef-ficients that represent the properties of the weak and strong interactions. The main instrument ofPERC provides a static magnetic field supported by a series of superconducting magnets, to col-lect and guide the charged decay e-/p+ particles from the decay to the detection area. To obtainhigh efficiencies and suppressed error levels, the strengths of the magnetic field have a functionaldistribution, with which the e-/p+ can be selected and defined due to their emission angles. Inorder to realize precise measurements, the decay e-/p+ are required to be transported with dis-tortion of the observables below 10−4. Hence the functional magnetic fields must be well definedand homogeneous. To fulfil the requirements of systematics and physics, the magnet system ofPERC is delicately designed with a dromedary geometry. The properties of the magnetic fields,the e-/p+ behaviors and the systematic effects are well studied in the simulations. Additionally,the practical and experimental factors are considered in the design of PERC, including the manu-facture requirements, the tolerances of the field functions due to external influences, the propertiesof superconducting wire, and the magnetic forces and torques on the components.

Fri, 10:08

Calibration of the ATLAS electromagnetic calorimeter at theper mill levelFlorian Teischinger1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria

ATLAS is one of the experiments built to explore new physics at the TeV with proton-protoncollisions at the Large Hadron Collider. The ATLAS experiment will briefly described with em-phasis on the ATLAS Liquid Argon electromagnetic calorimeter, this talk will concentrate on theperformance and calibration of the electron reconstruction during the 2011 and 2012 data takingperiods. Over the past years a calibration method for the energy scale of the liquid argon calorime-ter using the distribution of the ratio of the electron energy measured by the calorimeter itself andthe momentum measured by the Inner Tracking detector was developed. Results of this powerfulcalibration method using electrons from W and Z decays and combining the calorimetry and track-ing information, will be presented. It will be shown how scale factors in fine pseudo-rapidity binscan be extracted with a precision at the per mill level. These results will be compared to othercalibration methods used in ATLAS . It will be demonstrated how the linearity of the response ofthe electromagnetic calorimeter can be measured in situ and how the passive material in front of thecalorimeter can be estimated. Finally, the impact of this precise calibration of the electromagneticcalorimeter on selected physics measurements will be presented.

53

Fri, 10:20

The Integrated Simulation Framework – A novel DetectorSimulation Approach in the ATLAS Experiment

Elmar Ritsch1, Anna Usanova1, Peter Sherwood2, Francisca Garay Walls3, Andreas Schaelicke3,Andreas Salzburger4, Robert Duane Harrington Jr3, Julia Fischer5, Michael Duehrssen-Debling4

1University of Innsbruck, Technikerstraße 15, 6020 Innsbruck , Austria2University College London, Gower Street, London WC1E 6BT, UK

3The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK4CERN, 1211 Geneva 23, Switzerland

5Bergische Universitat Wuppertal, Gaußstrasse 20, 42119 Wuppertal, Germany

With the increasing amount of delivered luminosity by the Large Hadron Collider (LHC) atCERN, the demand for Monte Carlo simulated data grows accordingly. Given the computing re-sources of the ATLAS experiment this introduces strict requirements on detector simulation whichis, in general, a very CPU intensive task. The Integrated Simulation Framework (ISF) is a com-pletely new approach in optimizing ATLAS detector simulation given the need for high qualityphysics analyses on one side and restrictions on computing resources on the other. ISF builds aframework that allows to mix different simulation engines on a particle level for the same event.By doing so, a gain of simulation time per event can be achieved if particles which are less rel-evant for subsequent analysis are e.g. done using fast simulation approaches. ISF combines theexisting simulation engines used in ATLAS, which contain the Geant4 toolkit, a fast parameterizedcalorimeter simulation and a fast track simulation. This talk will discuss fundamental concepts,occurred problems that were solved during the design process of this framework along with firstresults obtained using the new ISF prototype in ATLAS.

Fri, 10:32

Radiation-hard silicon sensors for the CMS tracker upgradeBernhard Lutzer1


The Compact Muon Solenoid (CMS) experiment at the LHC at CERN is currently in opera-tion and delivering promising and outstanding results. This particle detector experiment consistsout of different types of detectors of which the Tracker is a very important one. It is made outof silicon-based strip detectors which perform very well at the moment. But due to the radiationdamage imposed on these detectors, caused by the high fluences in the near-to-interaction-pointregion these silicon strip detectors will loose their detection ability with time and need to be even-tually replaced by new a new tracker. Also the upgraded LHC which is planned to be in operationin 2020 will deliver a higher luminosity which requires very radiation-hard materials for the newdetectors. Therefore a campaign is undergoing to determine which material is the most suitablefor such challenging experimental conditions. Different materials for the wafer with different thick-nesses are characterized with test-structures and then irradiated with protons at Karlsruhe or withneutrons at TRIGA-reactors in Ljubljana or Vienna to simulate the conditions after several years ofoperation in the detector. These studies which are presented in this talk are conducted at HEPHYVienna and will support the decision for the material used for building the upgraded CMS tracker.

54

Fri, 10:44

Development and Production of Silicon Particle Detectors inAustria

Edwin Fruhwirth1


In particle physics experiments such as the Compact Muon Solenoid (CMS) experiment at theLarge Hadron Collider (LHC) at CERN large numbers of silicon based strip sensors are needed.These sensors are able to precisely detect particles generated in high energy proton-proton collisionsand therefore allow reconstructing particle tracks. So far only a few vendors were capable of pro-ducing silicon strip sensors with the quality needed in particle physics experiments. Together withan Austrian-based semiconductor manufacturer the Institute of High Energy Physics (HEPHY) (ofthe Austrian Academy of Sciences) developed such sensors. This talk presents the development,production and electrical characterization of the first silicon strip sensors produced in Austria. Theresults from the first measurements presented in this talk demonstrate the good quality of thenewly developed sensors and offer the possibility to establish the Austrian-based semiconductormanufacturer as a high quality vendor for particle physics detectors.

Fri, 11:00 - 11:30: Coffee break

55

Fri, 11:30 - 13:30, HS 15.03

Fri, 11:30

Monitoring of the radiation induced effects of the CMSTracker

Wolfgang Treberer-Treberspurg1


The tracker of the CMS experiment at the LHC presents the largest silicon device ever built.Although its functionality is addressed to particle physics it also presents a unique opportunity tostudy well documented radiation damage effects under very specific circumstances. During theirlifetime the silicon modules have to withstand up to E15 traversing particles per cm2. However, thesilicon sensor characteristic changes while ionizing radiation is damaging the crystal lattice. Eachof the 15148 modules is featured with a detector control unit, recording amongst other things everysingle temperature, dark current and voltage value. Periodically dedicated runs are performed todetermine the depletion voltage of each module. The dark current and its annealing behaviourin respect to temperature are measured as soon as the modules are turned on. All these dataare used in simulations to expand existing models and deliver predictions concerning the trackerperformance in the same time. The talk will present recent results, which have been considered infuture constructions of the tracker, especially concerning cooling.

Fri, 11:42

Belle II Silicon Vertex Detector: MechanicsImmanuel Gfall1, Thomas Bergauer1, Annekathrin Frankenberger1, Markus Friedl1,

Christian Irmler1, Manfred Valentan1, Paul Doljeschi1, Dusko Smiljic1


The Belle experiment at KEK in Tsukuba, Japan and its precision measurements have led tothe justification of the Nobel Prize earned by Kobayashi and Maskawa in 2008. In June 2010, themachine was brought to a halt for a promising future, namely an upgrade to Belle II which will becompleted until 2015. By this time all important components are to be exchanged for an unprece-dented performance boost of the accelerator (KEKB) and the Belle Detector. With this upgrade,KEKB will become SuperKEKB and beat its own luminosity world record (2.11× 1034cm−2s−1)by a factor of 40. The core of the Belle II Experiment is composed of a DEPFET Pixel Detec-tor, which is surrounded by the Silicon Vertex Detector (SVD). The SVD is located close to thebeam pipe to allow high precision vertex reconstruction. The proximity to the beam pipe and thehigh beam currents result in a very high level of background radiation for the SVD that both,the electronics and the mechanics have to cope with. The Origami sensor design was developedto provide a fast readout system at a very good signal to noise ratio. This design comes with agreat performance increase that is able to fulfill with the new Belle II requirements. Neverthelessit is important to implement a light and yet stable mechanical construction that can withstand theradiation and temperature conditions without compromising the detector capabilities.

56

Fri, 11:54

Belle II Silicon Vertex Detector: CoolingAnnekathrin Frankenberger1, Markus Friedl1, Thomas Bergauer1, Immanuel Gfall1,

Manfred Valentan1, Christian Irmler1, Paul Doljeschi1, Dusko Smiljic1


At the KEK, the High Energy Accelerator Research Organization in Tsukuba, Japan, currentlythe B-Factory KEKB and its experiment, the Belle detector get upgraded, aiming a higher lumi-nosity. The improved Super B-Factory will reach a luminosity of 8 × 1035cm−2s−1 which is 40times higher than the previous luminosity world record achieved there. For precise decay vertexmeasurements, a new silicon vertex detector (SVD) is required. The newly designed Belle II SVDcomes along with a modern cooling system. The new Belle II SVD with its new “Origami” readoutscheme requires an efficient cooling system for thermal control of the front-end electronics insidethe detector volume. One of the most important figures of merit for vertex detectors is the amountof material seen by particles traversing the detector, therefore the material budget has to be keptas low as possible. To minimize the material budget, an evaporative CO2 cooling system hasbeen chosen. CO2 provides excellent thermo-dynamical properties regarding its high heat transfercapability of evaporating CO2. This leads to a much smaller tube diameter and therefore lowermass inside the detectors active volume, compared to using fluorocarbons like conventional coolingsystems do. The 2PACL (Two-Phase Accumulator Controlled Loop) developed at Nikhef providesa stable and easily controllable detector cooling system, completely fulfilling the experiments re-quirements. Integrating the cooling system into the heart of the Belle II detector is difficult andinvestigations are ongoing to meet the required material budget and space constraints.

Fri, 12:06

Low-momentum track reconstruction in the vertex detectorof Belle II

Jakob Lettenbichler1, Rudolf Fruhwirth1, Moritz Nadler1


The vertex detector of the Belle II experiment will consist of two pixel layers (PXD) and fourdouble-sided strip layers (SVD). While tracks with a transverse momentum above ∼ 100 GeV/care seen in the Central Drift Chamber (CDC), tracks with lower transverse momentum, which areimportant in certain physics channels, have to be reconstructed in PXD and SVD only. Onlinetrack reconstruction, required for data reduction in the PXD, is even more difficult, as only thefour SVD layers can be used. We present the strategy for low-momentum track finding in theSVD and SVD/PXD system. It is based on a cellular automaton, which is preceded by severalfilter stages designed to reduce the combinatorics. The subsequent track fit is performed using theGENFIT toolbox, which has been adapted to the specific features of low-momentum pions andtheir interaction with the detector material. We present results from simulated data, includingbackground from the detector and the accelerator.

57

Fri, 12:18

Forward Tracking in a Linear Collider DetectorWinfried Mitaroff1, Robin Glattauer1, Rudolf Fruhwirth1


The International Large Detector (ILD) is one of two approved experiments at ILC, the globalproject for a future linear e-e+ collider with center-of-mass energy up to 1 TeV. A modified ver-sion is under study for CLIC, an alternative project for e-e+ collisions up to 3 TeV. The forwardtracking part of ILD (FTD) consists of silicon pixel and micro-strip disks between beam tube andcentral TPC. Precise track reconstruction in these regions relies on an efficient track search. Forprocessing the measurements of FTD within ILD’s software framework, we have developed a newand powerful stand-alone forward track search, based on 3 steps: a Cellular Automaton, a KalmanFilter, and a Hopfield Neural Network. We present this package, its methods and merits.

Fri, 12:30

Computational Uncertainties in Public BR(B → Xsγ) CodesSebastian Frank1, Sabine Kraml2, Nazila Mahmoudi3,4, Shibi Rajagopalan2

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria2LPSC Grenoble 53, rue des Martyrs 38026 Grenoble, France

3Laboratoire de Physique Corpusculaire Clermont-Ferrand, Campus des Czeaux 24, avenue des Landais BP 80026 63171 Aubire Cedex,France

4CERN, Office Building 53, 1211 Geneva 23, Switzerland

The branching ratio BR(B → Xsγ) is a sensitive probe for physics beyond the SM and thusan important constraint for parameter fits of SUSY models. It is therefore highly important tohave a good assessment of theoretical and computational uncertainties, including the differencesin the implementations and/or approximations used in public computational tools. We perform adetailed comparison of the various public BR(B → Xsγ) codes, evaluating the differences of theSM and MSSM results and their dependence on relevant parameters. The impact on SUSY fits isdemonstrated via a global Bayesian analysis using Markov Chain Monte Carlo (MCMC) techniques.

58

Fri, 12:42

Recovery Time and Double Hit Resolution Measurements ofSiPMs Using a Double Pulsed Laser

Lukas Gruber1, Stefan Brunner1, Catalina Curceanu2, Johann Marton1, Antonio Romero Vidal3,Alessandro Scordo2, Ken Suzuki1, Oton Vazquez Doce4

1Osterreichische Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria2NFN - LNF, Via E. Fermi 40, 00044 Frascati (Roma), Italy

3Universidade de Santiago de Compostela, Ra Xos Mara Surez Nez, 15782 Santiago de Compostela, Spain4Technische Universitat Munchen, James-Franck-Str. 1, 85748 Garching, Germany

The so-called Silicon Photomultiplier (SiPM) is a relatively novel type of semiconductor photodetector which consists of multiple pixels of Avalanche Photodiodes (APDs) working in Geiger-mode. One of the important parameters of photo sensors is the performance in high rate environ-ments. For experiments like AMADEUS within the KLOE detector at LNF, where the detectorsystem will be exposed to a very high rate shortly after the e+/e- injection, an overall rate ca-pability is required. A charged kaon decay-mode tagging to distinguish K+ and K- is also verycrucial to suppress the background. Therefore, a good double hit resolution is required. In order tocharacterize the rate capability and the double hit resolution, we performed an experimental studyto determine the cell recovery time for various SiPMs of different vendors. The measurements areperformed using a blue (407 nm) pulsed laser with 25 ps pulse width. We evaluated the recoverytime constant by measuring the sensor response to two consecutive laser pulses, with a varying rela-tive time difference of a few ns up to a few 100 ns, with a waveform digitizer (CAEN V1742, 5 GHzsampling). The two pulses are generated by splitting the laser signal, delaying one of the signalsand merging again. The delay of the second pulse is done by coupling the light into optical fibers ofdifferent length (1 m to 200 m). The influence of the overvoltage on the recovery time is also studied.

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60

5 Physics Teachers (LHS)HS 15.02

Physics in SchoolPhysik und SchuleLeopold Mathelitsch, [email protected]

Wednesday, 19th September 2012, HS 15.0214:30 - 15:00


14:30 - 15:00 Mario Muller Mikrokraftwerke


SchulerInnen stellen vorPresenter Title

Stefan MazuheliDie Teslaspule in Theorie und Experi-menten

Nadine Schmalzer Materiewelleninterferometrie

Thomas KamencekHalbleiter und Charakterisierung vonHalbleiternanostrukturen

Thomas MullederNanobeschichtungen – Nanotechnolo-gie in Theorie und Praxis

Physikolympiade 2012International Young Physicists’ Tournament 2012


16:15 - 16:30 Victor Franz Hess Prize16:30 - 17:00 Fachausschuss “Physik und Schule”

61

62

6 Acoustics (AKU)LS 15.02

AcousticsAkustikHolger Waubke, [email protected]

Thursday, 20th September 2012, LS 15.0210:00 - 11:00


10:00 - 10:20David Pirro

Alexander Wankhammer Acoustic Interface for Tremor Analysis

10:20 - 10:40 Matthias FrankQuellbreite von frontalen Phantom-schallquellen: Wahrnehmung, Mes-sung und Modellierung

10:40 - 11:00 Franz ZotterEinfache, auf Kammfilter beruhendePhantomschallquellenaufweitung



14:30 - 14:50 Holger WaubkeGaussian Closure Technik fur die Bes-timmung analytischer Losungen fur einhysteretisches Modell von Bouc

14:50 - 15:10 Peter BalazsFrame Theory for Acoustical Applica-tions

15:10 - 15:30 Thibaud NecciariAuditory time-frequency masking forstimuli with maximal concentration inthe time-frequency plane


63


15:50 - 16:10 Robert BaumgartnerModelle zur Vorhersage der Schallquel-lenlokalisation in Sagittalebenen

16:10 - 16:30 Harald ZiegelwangerBeschleunigung der nu-merischen Berechnung vonAußenohrubertragungsfunktionen

16:30 - 16:50 Michael Mihocic

ExpSuite: Software Framework zurDurchfuhrung psychoakustischer Ex-perimente mit akustischer, elektrischerund visueller Stimulusdarbietung

16:50 - 17:10 Christian KasessBayesian estimation of the area func-tion of nasals

17:10 - 17:30 Wolfgang Kreuzer Wavelets on the sphere

17:30 - 17:50 Martin PobitzerEigenmoden – Raummoden; theoretis-che Betrachtungen und Simulationenin COMSOL Multiphysics

64

Thu, 10:00 - 11:00, LS 15.02

Thu, 10:00

Acoustic Interface for Tremor AnalysisDavid Pirro1, Alexander Wankhammer1, Alois Sontacchi1, Robert Holdrich1

1Universitat fur Musik und darstellende Kunst Graz, Inffeldgasse 10/3, 8010 Graz, Austria

Tremor is the most common movement disorder. It is defined as a rhythmic and involuntaryoscillation of a body part, caused by reciprocal nervous innervations of muscles. The most com-mon forms include the essential tremor, parkinsonian tremor, dystonic tremor and psychogenictremor. It is well-known that each different tremor form can be the symptom of a specific disease.Therefore, reliable classification and quantification of different tremor types is of strong clinicalinterest, as it could be crucial in order to provide adequate treatment and medication for the pa-tient. In many cases a confident clinical diagnosis mainly based on the visual analysis of a tremorby highly specialized neurologists experienced in movement disorders is possible. Nevertheless,in some situations uncertainty remains. Therefore, further investigations based on structural andfunctional imaging, video analysis, accelerometry and other electrophysiological investigations canbe necessary. Although such methods offer important additional information for a final diagnosis,the ex-post analysis and interpretation of recorded data is typically very time-consuming and ex-pensive. The new sonification methods presented in this paper aim at extending established tremoranalysis methods by an acoustical interface for tremor diagnosis. Based on real time sonification ofacceleration data, detailed information on the temporal as well as spectral characteristics of tremorcould be made audible to the neurologist while interacting with the patient. As sonification couldprovide an additional modality to perception, it would allow for a holistic analysis of the observedtremor avoiding the major drawbacks of ex-post analysis methods.

Thu, 10:20

Quellbreite von frontalen Phantomschallquellen:Wahrnehmung, Messung und Modellierung

Matthias Frank1


Phantomschallquellen sind Horereignisse, die an einem Ort wahrgenommen werden, an demsich keine Schallquelle befindet. Die einfachste Art Phantomschallquellen mithilfe von Lautsprech-ern zu erzeugen stellt die Stereophonie dar. Phantomschallquellen unterscheiden sich in ihrerwahrgenommenen Qualitat von realen Schallquellen. Einer dieser Unterschiede ist eine Aufweitungder wahrgenommenen Quellbreite. Dieser Beitrag beschaftigt sich mit der Quellbreite von frontalenPhantomschallquellen. Die Phantomschallquellen werden durch gleichzeitigen Betrieb von 2 bzw. 3symmetrisch aufstellten Lautsprechern erzeugt. Neben der Anzahl an aktiven Lautsprechern wirdauch der Abstand zwischen diesen variiert. Die Wahrnehmung der Quellbreite wird zunachst ineinem Horversuch evaluiert. Die Versuchsergebnisse werden anschließend mit zwei aus der Rau-makustik bekannten Messgroßen fur die Quellbreite (interauraler Kreuzkorrelationskoeffizient IACCund Seitenschallgrad LF) verglichen. Weiters wird eine angepasste Methode zur Messung des Seit-enschallgrades vorgestellt, die die Eignung dieser Messgroße fur simultanen Schalleinfall verbessert.Der Beitrag schließt mit einem einfachen physikalischen Modell zur Vorhersage der wahrgenomme-nen Quellbreite.

65

Thu, 10:40

Einfache, auf Kammfilter beruhendePhantomschallquellenaufweitung

Franz Zotter1, Matthias Frank1


Die geeignete Ansteuerung eines symmetrisch zum Horplatz stehenden Lautsprecherpaareskann ein Horereignis variabler Breite erzeugen. Am schmalsten ist dieses Horereignis, die so genan-nte Phantomschallquelle, wenn beide Lautsprecher mit dem selben Signal versorgt werden. Esist allgemein bekannt, dass sich die wahrgenommene Richtung dieser Phantomschallquelle durchbreitbandige Laufzeit- und Pegelunterschiede an variable Richtungen zwischen den Lautsprechernlenken lasst. Daruber hinaus beschreibt die Literatur uber Stereophonie, dass entlang der Fre-quenz uneinheitliche Pegel- und Laufzeitunterschiede dazu geeignet sind, die Phantomschallquelleaufzuweiten. Eine kurzlich vorgestellte laufzeitbasierte Methode ist zwar effizient, scheint aber nuram zentralen Abhorplatz gut zu funktionieren. Dieser Beitrag stellt deshalb einen effizienten pegel-basierten Ansatz vor und vergleicht beide Ansatze an einem seitlichen Abhorplatz.

66

Thu, 14:30 - 15:30, LS 15.02

Thu, 14:30

Gaussian Closure Technik fur die Bestimmung analytischerLosungen fur ein hysteretisches Modell von Bouc

Holger Waubke1

1Osterreichische Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

Das Modell von Bouc wurde fur die mathematische Beschreibung des hysteretischen Verhaltensvon Gummi entwickelt [1]. Im Vortrag sollen weitgehend analytische Beschreibungen fur die Mo-mente einer mehrdimensionalen Normalverteilung der Zustandsgroßen des Modells von Bouc aufBasis der Gaussian Closure Technik [2] gewonnen werden. Dabei wird ein explizites Zeitschrittver-fahren fur den instationa ren Fall und ein implizites nichtlineares Gleichungssystem fur den sta-tionaren Fall hergeleitet [3]. Das implizite Gleichungssystem laßt sich rasch losen. Dabei tretenkeine Parameterkombinationen auf, die zu chaotischen Verhalten, wie bei der statistischen Lin-earisierung fuhren.

[1] Bouc, R.: Forced Vibrations of a Mechanical System with Hysteresis (abstract), Proceedings ofthe 4th Conference on Nonlinear Oscillations, Prag, 1967, pp.315[2] Caughey, T.K.; Dienes, J.K: Analysis of a Nonlinear First-Order System with a White NoiseInput, Journal of applied Physics, Vol.33 No.11 Nov. 1961, pp. 2476-2479[3] Waubke, H. : Moment-Closure Technik zur Abschatzung der elasto-plastischen Reaktion vonStockwerksrahmen auf zufallige Belastungen aus Windereignissen, Habilitation, Berichte aus demkonstruktiven Ingenieurbau, TU Munchen, 1/1999

Thu, 14:50

Frame Theory for Acoustical ApplicationsPeter Balazs1


Application-oriented mathematics develops theoretical results and new mathematical concepts,motivated by application. The application-oriented approach produces results significant both formathematics and the applied sciences. In this talk we will present an overview of new concepts inframe theory motivated by signal processing and acoustical applications. We will present a surveyover general frame theory, time-frequency analysis and the theory of frame multipliers, as well atheir applications in acoustics.

67

Thu, 15:10

Auditory time-frequency masking for stimuli with maximalconcentration in the time-frequency plane

Thibaud Necciari1, Bernhard Laback1, Peter Balazs1, Sophie Savel2, Sabine Meunier2,Sølvi Ystad2, Richard Kronland-Martinet2

1Osterreichische Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria2Laboratoire de Mecanique et dAcoustique, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France

Many audio applications involving sound analysis-synthesis (e.g., virtual reality, sound design,perceptual audio coding) use time-frequency (TF) representations such as the Gabor and wavelettransforms. These transforms allow decomposing any natural sound into a set of elementary func-tions or “atoms” that are well localized in the TF plane. For such applications, it is often requiredthat the signal representation matches human auditory perception. On that purpose, the presentstudy investigated auditory TF masking using stimuli with maximal concentration in the TF plane.Stimuli (masker and target) were Gaussian-shaped sinusoids with an equivalent rectangular band-width of 600Hz and an equivalent rectangular duration of 1.7ms (0-amplitude duration of 9.6ms).The masker had a carrier frequency of 4kHz and a level of 60dB SL. The target was shifted eitherin time, in frequency, or both relative to the masker. The results of the TF shifts provide the TFspread of masking produced by a maximally-compact Gaussian TF atom. These results constitutea crucial basis for predicting masking in the TF representations of sounds. The results of the timeand frequency shifts allowed to show that a simple superposition of frequency and temporal mask-ing functions does not provide an accurate representation of the measured TF masking function.This reveals the inaccuracy of the simplistic models of TF masking currently implemented in someperceptual audio codecs.


68

Thu, 15:50 - 18:00, LS 15.02

Thu, 15:50

Modelle zur Vorhersage der Schallquellenlokalisation inSagittalebenen

Robert Baumgartner1, Piotr Majdak1, Bernhard Laback1


Die Fahigkeit, Schallquellen in Sagittalebenen zu lokalisieren, basiert auf spektralen Merk-malen, die aus der Filterung des einfallenden Schalls durch Torso, Kopf und Ohrmuschel resultieren.Obwohl diese Filterwirkung bereits seit langer Zeit bequem mittels sog. head-related transfer func-tions (HRTFs) beschrieben werden kann, erlauben derzeitige Modelle noch nicht die Vorhersageder Schallquellenlokalisation in Sagittalebenen. Dieser Beitrag beschreibt existierende Modelle zurVorhersage der Schallquellenlokalisation sowie mogliche Erweiterungen fur den verbesserten Vergle-ich mit psychoakustischen Experimenten. Es wird eine Methode zur Vorhersage der individuellenLokalisationsleistung mit individuellen HRTFs vorgestellt. Weiters wird der Effekt der Einbettungverschiedener Modelle des peripheren Gehors im Lokalisationsmodell auf die Vorhersage der Lokali-sation unter diversen Bedingungen beschrieben.

Thu, 16:10

Beschleunigung der numerischen Berechnung vonAußenohrubertragungsfunktionen

Harald Ziegelwanger1, Wolfgang Kreuzer1, Piotr Majdak1


Außenohrubertragungsfunktionen (engl. head-related transfer functions, HRTFs) ermoglichendie Lokalisation von Schallquellen bei binauraler oder transauraler Wiedergabe und werden ublicherWeise in einem reflexionsarmen Raum unter Freifeldbedingung fur eine begrenzte Anzahl an Posi-tionen akustisch gemessen. Die Berechnung von HRTFs uber die Randelementemethode stellt einegut geeignete Alternative dar, da sie unter Ausnutzung der Reziprozitat (Tausch von Quelle undEmpfanger) effizient die Simulation des durch den Zuhorer gestorten Schallfeldes im Freifeld undsomit die Berechnung der HRTFs fur beliebige Positionen im Raum ermoglicht. Dafur genugt alleindie Kenntnis der Geometrie von Pinna, Kopf und Torso, welche die Filterwirkung verursacht unddurch bildgestutzte Messverfahren (3D-Laserscan) oder durch bildgebende Messverfahren (Kern-spintomographie) als 3D-Mesh erfasst werden kann. Um die HRTFs fur den gesamten horbarenFrequenzbereich berechnen zu konnen, muss das zugrundeliegende Mesh eine hohe Genauigkeitaufweisen (ca. 6-10 Elemente pro Wellenlange). Eine hohere Genauigkeit bewirkt allerdings einelangere Rechendauer bei der Simulation. In diesem Vortrag werden verschiedene Ansatze zur Re-duktion der Rechendauer bei der HRTF-Berechnung uber die Randelementemethode vorgestellt. Eswerden numerische Optimierungen wie zum Beispiel ein parametrisches Mesh, die Fast-Multipole-Methode oder H/H-Matrizen diskutiert. Aufgrund der optisch schwer erfassbaren und komplexenStruktur der Pinna wird vorgeschlagen ein strukturiertes Pinna-Modell zu entwickeln und an dieindividuelle Anthropometrie anzupassen.

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Thu, 16:30

ExpSuite: Software Framework zur Durchfuhrungpsychoakustischer Experimente mit akustischer, elektrischer

und visueller StimulusdarbietungMichael Mihocic1, Piotr Majdak1, Bernhard Laback1


In diesem Beitrag wird ExpSuite, eine Software zur Durchfuhrung psychakustischer Experi-mente vorgestellt. ExpSuite besteht aus einem Framework und darauf basierenden Applikationen.Sie profitiert von der “Rapid Application Development”-Umgebung in .NET, die eine schnelleEntwicklung der Experimente ermoglicht. Durch den modularen Aufbau konnen Applikation-sprogrammierer die Eigenschaften der Applikationen selbst definieren: Generierung einer “Itemlist” mit Testparametern und Ergebnissen, Erzeugung und Wiedergabe der Stimuli, Ablauf desExperiments und Auswertung der Ergebnisse. Das Framework unterstutzt prozedurale Eigen-schaften wie zeitliche Struktur (adaptive und ineinander verschachtelte Ablaufe), Parametrierungexperimenteller Schritte, Steuerung uber Joypad, Maus, Tastatur, Touchscreen, oder Position-serfassungsysteme. Damit kann sich der Applikationsprogrammierer auf die Entwicklung des ex-perimentellen Designs konzentrieren. Mit der direkten Anbindung an Matlab steht ExpSuite-Applikationen eine Vielfalt von Matlab Funktionen zur Verfugung, die auch zur direkten Auswer-tung der Ergebnisse verwendet werden konnen. Die Ausgabe der Stimuli in vektororientierterForm kann uber akustische Audiogerate oder als elektrische Stimulation uber ein Cochleaimplantat-Interface erfolgen. Das Programm Pure Data (pd) ubernimmt die akustische Signalverarbeitungin Echtzeit (komplexe Filterung und Signalgenerierung), die Ausgabe der Stimulationsdateien,sowie die simultane Aufnahme und Wiedergabe mehrerer Audiokanale. Zur Echtzeitdarstellungeiner virtuellen visuellen Welt wird GEM unter pd verwendet. Die elektrische Stimulation zurDurchfuhrung von Experimenten mit Cochleaimplantat-Tragern erfolgt uber die Research InterfaceBoxen (RIBs), die eine binaural synchronisierte Stimulation von Implantaten unterstutzen. Exp-Suite wird am Institut fur Schallforschung entwickelt und ist unter http://expsuite.sourceforge.netfrei verfugbar.

Thu, 16:50

Bayesian estimation of the area function of nasalsChristian Kaseß1, Wolfgang Kreuzer1


Computational acoustical models for speech production and analysis have been of major re-search for decades. Most commonly, one-tube models are employed which show a direct correspon-dence to all-pole filter models. However, such models are not an adequate representation for nasalstops and nasalized vowels due to the coupling to the nasal tract. Thus, at least one additionalcoupled tube is necessary to model the spectral dips typically appearing in nasal speech signals.Typically, the estimation of such branched-tube area functions is based on pole-zero models. Here,the tube model areas are estimated directly from the log-envelope of the spectrum of the speechsignal. A variational Bayesian scheme under Gaussian assumptions is employed that utilizes prob-abilistic priors to enforce smoothness of the estimated area function. Different prior variances aretested on tokens of /m/ recorded from several speakers. Furthermore, results of an un-regularizednon-linear scheme are compared to the Bayesian estimation. The model error and marginal likeli-hood show that mild smoothness assumptions yield the best results. The estimation error for theun-regularized scheme is in a comparable range, however, the reflection coefficients and thus thearea functions vary considerably more within a subject than for the Bayesian scheme.

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Thu, 17:10

Wavelets on the sphereWolfgang Kreuzer1


For numerous applications in acoustics a spatial representation of wave fields supporting a localother than a global resolution is advantageous. Such applications range from wave field synthesis tonumerical methods like the fast multipole method. As an alternative to the often applied sphericalharmonic analysis, wavelets or - more general - frames can achieve a more efficient representation.Although wavelet analysis has been proven to be useful in many applications in audio and signal-processing and wavelets on the sphere have been of research interest in geophysics and computervision for several years now, their potential for representing three-dimensional acoustic wave fieldshas not been fully explored yet. In this talk, a short overview of available methods to constructand use wavelets (and frames) on the sphere will be presented.

Thu, 17:30

Eigenmoden - Raummoden; theoretische Betrachtungen undSimulationen in COMSOL Multiphysics

Martin Pobitzer1, Stefan Plagg1, Gerhard Graber1

1Graz University of Technology (TU Graz), Inffeldgasse 16c/EG, 8010 Graz, Austria

Dieser Beitrag beschaftigt sich mit der Ausbildung von stehenden Wellen im Raum. Da indiesem Zusammenhang die Begriffe “Eigenmoden” und “Raummoden” oft verwechselt werden,ist einer der Kernpunkte die Unterschiede beider Begriffe aufzuzeigen. Nach einer Einfuhrung indie Thematik wird eine Eigenfrequenzanalyse fur verschiedene Raumtypen durchgefuhrt und derEinfluss von verschiedenen Wand- und Deckenformen untersucht. Die Ergebnisse werden unteranderem mit Hilfe von Animationen prasentiert. Der zweite Teil behandelt die Frequenzbereich-sanalyse, mit deren Hilfe der Einfluss von Quellposition und Beobachter- bzw. Mikrofonpositionauf die Raummodenausformung untersucht wird.

Die Arbeit wurde im Rahmen eines Bachelorseminars am Institut fur Signalverarbeitung undSprachkommunikation (spsc) der Technischen Universitat Graz erstellt.

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72

7 Atoms, Molecules, Quantum Optics and Plasmas(AMP)LS 15.01

Atoms, Molecules, Quantum Optics and PlasmasAtome, Molekule, Quantenoptik und Plasmen:Hanns-Christoph Nagerl, [email protected]



09:00 - 09:20 Thomas BetzCarbohydrate-Aromatic ComplexesInvestigated by Broadband MicrowaveSpectroscopy

09:20 - 09:40 Andreas HauserThe calculation of ESR line shifts ofalkali-metal atoms (Li, Na, K, Rb) onhelium nanodroplets

09:40 - 10:00 Thorsten SchummNon-linear atom optics with Bose-Einstein condensates

10:00 - 10:20 Michele SclafaniAbsolute single molecule detection effi-ciency for a superconducting nanowire

10:20 - 10:40 Christian GruberControlled coupling of quantum dotsto nanowire plasmons

10:40 - 11:00 Franz SchmidtEEL-mapping of plasmon modes on asilver nano disk




14:30 - 14:50 Laurin OstermannSuperradiance and cascaded decay ofregular arrays of trapped atoms

14:50 - 15:10 Florian LacknerRubidium atom Rydberg states per-turbed by superfluid helium nan-odroplets

15:10 - 15:30 Carolina MatiasLaser induced acoustic desorption ofbiomolecules


73



15:50 - 16:10 Andreas HohenauRoughness and crystallinity contri-butions to surface-enhanced light-molecule interactions

16:10 - 16:30 Andreas KautschFano resonances in photoionizationspectra of chromium in helium nan-odroplets

16:30 - 16:50 Katrin Tanzer Electron Interactions with Explosives

16:50 - 17:10 Johann PototschnigQuantum chemical studies of Cr atomson superfluid He nanodroplets

17:10 - 17:30 Laurentius WindholzCombination of Fourier transform- andlaser spectroscopy to find unknownatomic energy levels

17:30 - 17:50 Bettina GamperNew energy levels of the neutral Pratom in the IR region

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Thu, 09:00 - 11:00, LS 15.01

Thu, 09:00

Carbohydrate-Aromatic Complexes Investigated byBroadband Microwave Spectroscopy

Thomas Betz1,2, David Schmitz1,2, Alvin Shubert1,2, Melanie Schnell1,2

1Center for Free-Electron Laser Science, Notkestrasse 85, 22607 Hamburg, Germany2Max-Planck-Institut fur Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany

A new broadband microwave spectrometer for the structural investigation of biologically rel-evant molecules in the gas phase is presented. The set up will be used to study the recognitionof cyclic carbohydrates and aromatic molecules. This interaction is of significant importance inbiological systems, for example, the recognition of cells by lectins. The carbohydrate partnerswill be represented by gluco-, galacto and fucopyranose, whereas benzene, indole, and tryptophanserve as model molecules for the aromatic recognition sites. The complexes will be formed bysimultaneously seeding them into a supersonically expanding noble gas. The rotational spectraof these complexes will be recorded by employing the novel Chirped Pulse Fourier Transform Mi-crowave (CPFTMW) spectroscopy technique1. This will allow the fast acquisition of the molecularresponse to microwave radiation in the range of 2 to 8 GHz and thus enables the comparison ofdifferent molecular Earlier investigations used infrared ion dip (IRID) vibrational spectroscopy tocharacterize the involved binding mechanism of these systems2. Measuring the rotational spectrawill complement this work by allowing the direct investigation of the structure of the molecularcomplexes. This knowledge will deepen the understanding of the conformational properties andchanges involved in the recognition process.

Thu, 09:20

The calculation of ESR line shifts of alkali-metal atoms (Li,Na, K, Rb) on helium nanodroplets

Andreas Hauser1, Thomas Gruber1, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

The line positions of electron spin resonance transitions (ESR) in alkali atoms are shifted foratoms attached to superfluid helium nanodroplets [1]. First attempts to describe the observeddependence of the hyperfine structure constant on the droplet size were based on a perturbationalapproach to the interaction between the He-cluster and the dopant, using the excited states of freealkali-metal atoms as basis sets for the matrix representation of the perturbation operator [2,3]. Inan alternative approach we start from the analysis of the He-X dimers (X = Li, Na, K, Rb) withstandard methods of quantum chemistry. Spin densities at the alkali atom, causing the isotropicpart of the hyperfine interaction, can be calculated rather easily from most program packages atthe Hartree-Fock (HF) level. Unfortunately, the weak van der Waals interactions between alkaliatom and helium have to be treated at post-HF levels to obtain reasonable results. At least for Rbthe inclusion of relativistic corrections is also indispensable. Furthermore, the experimental clustersizes are out of range for any code based on molecular orbital theory. As a consequence, we try toreproduce the observed shifts by combining relativistic ab initio calculations for the He-X dimersystems with a simulation of full helium droplets based on density-functional theory.

[1] Koch, M., Aubock, G., Callegari, C., Ernst, W. E., Phys. Rev. Lett. 103(3), 03530214(2009)[2] Koch, M., Callegari, C., Ernst, W. E., Mol. Phys. 108, 10051011(2010)[3] Callegari, C., Ancilotto, F., J. Phys. Chem. A 115, 67896796(2011)

75

Thu, 09:40

Non-linear atom optics with Bose-Einstein condensatesThorsten Schumm1, Tarik Berrada1, Jean-Francois Schaff1, Sandrine Van Frank1, Robert Bucker1,

Jorg Schmiedmayer1

1Technische Universitat Wien - Atominstitut, Stadionallee 2, 1020 Wien, Austria

Realizing building blocks of photon quantum optics for matter waves is a long-standing goal.We present an efficient source for twin-atom beams, in analogy to parametric down-conversionin non-linear optics. The source shows strong non-classical correlations in the population of thetwo beams, - 10dB below the classical limit. We also realized an integrated Mach-Zehnder inter-ferometer for matter waves by combining a spatial beam splitter for BEC, a gravity-dependentphase-shifter and a recombined based on a pulsed Josephson tunnel junction. The intrinsic non-linearity of the matter waves leads to number squeezing in the splitting process and to fundamentalphase diffusion in the interferometer sequence. We will discuss performance limits towards matterwave metrology.

Thu, 10:00

Absolute single molecule detection efficiency for asuperconducting nanowire

Michele Sclafani1, Markus Arndt1

1University of Vienna, Boltzmanngasse 5, 1090 Wien, Austria

We present a study of the absolute single-particle detection efficiency of a 100 nm wide 4 nmthick NbN meander for ions in the low kinetic energy regime (0.2-1 keV) . We prove the capabilityof recording atomic and molecular ion signals in an energy range much lower than typically used inmass spectrometry and we show that up to a 100% detection efficiency can be achieved within ourexperimental setting. Superconducting nanowire devices have recently been proposed as an idealalternative detection scheme for ionized [1,2] and neutral [3] particle beams. The detection processrelies on the local suppression of superconductivity as the kinetic energy of the incoming particleis transferred to the electronic system of the wire. The impact of a molecule with the detectorsurface results in the rise of a resistive nanosecond voltage pulse when the wire is biased with aconstant current. Finally we focus on the role of surface adsorbates in the detection process, whichhas remained neglected in all previous study so far, and we suggest new future strategies for opticalspectroscopy on molecules, nanoparticles or helium nanodroplets.

[1] M. Sclafani et al., Nanotechnology 23 (2012)[2] K. Suzuki et al., Rapid Communication Mass Spectrometry 24 (2010)[3] M. Marksteiner et al, Nanotechnology 20 (2009)

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Thu, 10:20

Controlled coupling of quantum dots to nanowire plasmonsChristian Gruber1, Primoz Kusar1, Andreas Hohenau1, Joachim Krenn1

1University of Graz, Universitatsplatz 5, 8010 Graz

The diameter of dielectric waveguides is limited by the wavelength of the guided light. Incontrast, gold and silver nanowires can sustain propagating plasmon modes even for significantlysmaller dimensions. Furthermore the strong field localization of the nanowire plasmon modesleads to a strong interaction with nearby quantum emitters such as quantum dots. We use electronbeam lithography, first, to fabricate silver nanowires and, second, to position a few dots close to onenanowire end in a template-assisted process. Scanning a focused laser spot over the nanowire ends,we demonstrate both, the excitation of nanowire modes by quantum dots and the addressing of thesame dots by plasmons. We use the fluorescence signals to quantify the quantum dots/plasmon cou-pling and show that part of the plasmon-induced dot fluorescence couples back to plasmonic modes.

Thu, 10:40

EEL-mapping of plasmon modes on a silver nano diskHarald Ditlbacher1, Franz Schmidt2, Ulrich Hohenester1, Andreas Hohenau1, Ferdinand Hofer2,

Joachim Krenn1

1University of Graz, Universitatsplatz 5, 8010 Graz2Graz University of Technology, FELMI, Steyrergasse 17, 8010 Graz, Austria

Localized surface plasmons are collective oscillations of the conducting electrons of metal nanostructures coupled to an evanescent electromagnetic field. We study the plasmonic eigenmodes ofa silver nano disk with laterally resolved electron energy loss spectroscopy (EELS) and observe –beside the well-known dipolar, quadrupolar, hexapolar etc. modes – a new type of modes whichwe name breathing modes analogous to acoustic vibrations. The surface charge distributions ofdipolar and multipolar modes show radial node lines whereas the node lines of breathing modesare circles. These breathing modes are elementary plasmonic excitations of metal nano disks whichhave not been observed up to now as they do not couple to propagating light fields efficiently. Thismeans these modes can hardly be detected by optical far field spectroscopy and they are thereforecalled “dark” modes. Nevertheless these modes affect the coupling of nano disks with moleculardipoles or other metal nano structures.


77

Thu, 14:30 - 18:00, LS 15.01

Thu, 14:30

Superradiance and cascaded decay of regular arrays oftrapped atoms

Laurin Ostermann1, Helmut Ritsch1, Hashem Zoubi1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria

Lifetime and energy of collective optical excitations in regular arrays of atoms are significantlymodified by dipole-dipole interaction. While the limiting cases of very closely positioned or infi-nite arrays of regularly spaced atoms can be approximated well by the Dicke superradiance or anexciton-based model, the situation of finite regular configurations is hard to access analytically.So far, most treatments are restricted to the lowest excitation manifold and a truncation of theinteraction length We develop a general approach covering the complete decay cascade from thefully inverted to the ground state. We explicitly calculate all shifts and decay rates for the twogeneric cases of a 3-atom linear chain and an equilateral triangle and show their relation. In nu-merical calculations we show that despite fairly weak two-partite interactions, significant effectscan build up in larger arrays through multi-particle interference. This changes the dephasing anddecay properties in Ramsey experiments as well as the stability of superradiant lasers on narrowatomic lines as atomic clock transitions.

Thu, 14:50

Rubidium atom Rydberg states perturbed by superfluidhelium nanodroplets

Florian Lackner1, Gunter Krois1, Markus Koch1, Wolfgang Ernst1


Spectroscopy of rubidium atoms on the surface of helium droplets (HeN) of different sizes givesinformation about the influence of a nanosized superfluid on rubidium Rydberg states. We presentthe excitation spectrum of the Rb-HeN system from the 52D state manifold up to the ionizationthreshold, recorded by resonant three-photon-ionization time-of-flight spectroscopy [1, 2]. In ad-dition to transitions from the 52P1/2 intermediate state into nS and nD states, transitions intonP and nF states are observed. These transitions are allowed because of the reduced symmetry ofthe Rb-HeN system, which has a diatomic-like character. The observed transitions are broadenedand shifted with respect to bare atom states, which is explained by a decreased quantum defectand a lowered ionization threshold within the scope of a Rydberg model. A set of six Rydbergseries could be identified. Individual Rydberg states are observed with effective principle quantumnumbers up to n∗ ≈ 19 and l ≤ 3, for which the expectation value of the electron orbital radius isabout 10 times larger than the droplet radius.

[1] Lackner, F., Krois, G., Koch, M., Ernst, W.E., J. Phys. Chem. Lett. 3, 1404-1408 (2012)[2] Lackner, F., Krois, G., Theisen, M., Koch, M., Ernst, W.E., Phys. Chem. Chem. Phys., 13,18781-18788 (2011)

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Thu, 15:10

Laser induced acoustic desorption of biomoleculesCarolina Matias1, Johannes Postler1, David Gschliesser1, Marcelo Goulart1, Paul Scheier1,

Stephan Denifl1

1University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria

When high energy radiation interact with living cells it creates, along the ionization track, a setof secondary species. Low energy (<20eV) electrons are the most abundant ones and can inducestrand breaks in DNA. The investigation of the influence of secondary particles in biomolecularsystems, whether in the gas phase or in condensed phase, is a rich research area which appliesboth to gain fundamental knowledge and application-oriented results. Previous mass spectrometryexperiments with low energy electrons dealt with small DNA building blocks and protein in thegas phase. In this work we perform free electron attachment studies to more complex systems likenucleotides. Typical experimental setups use ovens in which a sample of a certain biomolecule isheated and thereby evaporated. With the increasing size of the molecules there is a high risk ofthermal decomposition. The advantage of using laser induced acoustic desorption is that one canprevent thermal decomposition and evaporate large molecules unbroken. The sample is applied as avery thin film on a thin metal foil, and then the foil is irradiated at the backside with a pulsed laser.The laser pulses will create an acoustic wave, which propagates through the metal and desorbs thesample from the surface. Such a technique enables us to get large DNA building blocks or proteinsinto the gas-phase and makes it possible to investigate pure electron molecule interactions. Thisgives us important basic insight into the reactions happening in radiation damage.


79

Thu, 15:50 - 18:00, LS 15.01

Thu, 15:50

Roughness and crystallinity contributions tosurface-enhanced light-molecule interactions

Andreas Hohenau1, Joachim Krenn1, Jean-Claude Tinguley1


Noble metal nanoparticles show specific optical properties due to the excitation of localizedsurface plasmons that give rise to surface enhanced absorption, fluorescence or Raman scattering.The nanoparticle geometry the dielectric properties of the metal and nanoscale surface rough-ness play an important role for surface enhanced effects, however they not yet well understoodfor lithographically fabricated nanoparticles. We approach this question by analyzing the opticalcharacteristics of lithographically fabricated nanoparticles with different crystalinity and roughnessparameters. They are varied by thermal annealing and a thin gold film is applied as a model systemto retrieve modifications in the dielectric function. We investigate, on one hand, extinction spectraof metal nanoparticles that reflect the far-field properties of the plasmonic excitation and, on theother hand, surface-enhanced Raman spectra that serve as a near-field probe. Our results provideimproved insight into localized surface plasmons and their application in light-molecule interactions.

Thu, 16:10

Fano resonances in photoionization spectra of chromium inhelium nanodroplets

Andreas Kautsch1, Matthias Hasewend1, Martin Ratschek1, Markus Koch1, Wolfgang Ernst1


Ultracold He nanodroplets (HeN) at 0.4 K serve as ideal matrix to isolate and analyze singleatoms with supporting effects from the interaction with the surrounding He [1]. Resonance ioniza-tion mass spectroscopy (RIMS) is a versatile technique to selectively excite and detect atoms. Wecombined these methods and carried out resonant two-photon ionization (R2PI) measurements onCr atoms in HeN in the wavelength range from 350 to 361 nm (27700 - 28600 cm−1). Possiblepathways leading to ionization include a strong first step y7P◦ ← a7S transition happening insidethe droplet. This results in a broadening and a blue shift of about 7 nm enabling the possibilityto obtain detailed information about the perturbation upon electronic excitation of the Cr atomin HeN [2]. Subsequently, the Cr atom leaves the droplet and simultaneously relaxes into lowerlying states, which are spin and parity forbidden transitions. With a second photon of the samecolour the ionization is accomplished through either continuum or autoionization states. We char-acterized Fano type resonances in terms of laser fluence saturation to get further insight into thevarious processes.

[1] Ratschek, M., Koch, M., and Ernst, W. E., J. Chem. Phys. 136, 104201 (2012).[2] Callegari, C., and Ernst, W. E., in Handbook of High-Resolution Spectroscopy, eds. Quack, M.,and Merkt, F., John Wiley & Sons, Chichester, 2011.

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Thu, 16:30

Electron Interactions with ExplosivesKatrin Tanzer1, Benjamin Puschnigg1, Violaine Vizcaino1, Stephan Denifl1, Paul Scheier1

1University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria

In recent years a considerable interest in improving methods for the detection of explosiveshas arisen since the threat of attacks on planes and high risk buildings has grown steadily. Twomethods for the detection working with electron-molecule collisions and mass spectrometry arepresented and compared. Electron attachment of low energy electrons often leads to dissociation.In the case of explosive substances, every single explosive has a rich characteristic fragmentationpattern. This has been measured in our group for the explosives RDX and PETN amongst oth-ers. Together with the resonance profiles of the fragments even the distinction between isomersis possible, as shown for the three DNB isomers. Another possible technique for the detection ofexplosives is electron ionization where cations are formed by impact of electrons of about 70 eV.Usually considered a “hard” ionization method, electron ionization also leads to rich fragmentationpatterns. Together with the ion efficiency curves and especially the appearance energy they form aunique fingerprint for every explosive. Mass spectra and appearance energies have been determinedfor several explosives including RDX, PETN and TNB. Considerable differences have been foundeven for the DNB isomers.

Thu, 16:50

Quantum chemical studies of Cr atoms on superfluid Henanodroplets

Johann Pototschnig1, Martin Ratschek1, Andreas Hauser1, Markus Koch1, Wolfgang Ernst1


He nanodroplets (HeN) provide a superfluid quantum matrix at 0.4 K. Single atoms or moleculesdoped on HeN can be investigated and used to synthesize nanostructures that may be depositedon surfaces [1]. The location of the dopant on HeN affects the amount of spectroscopic pertur-bation and the formation of nanostructures on HeN. Cr has outstanding magnetic properties dueto the septet ground state. In combination with He, a weak van der Waals molecule is formedwhich is challenging to describe theoretically. We calculated the Cr-He pair potential curve withdifferent post Hartree-Fock methods. CCSD(T), CI, and multireference perturbation theory (RS)were applied, all including relativistic Douglas-Kroll corrections. After counterpoise correction weextrapolated to the basis set limit. The pair potential is applied to calculate the so-called Ancilottoparameter [2] and to DFT calculations for the He density [3]. Both methods indicate that Cr residesinside HeN. Our group also investigates the Cr-HeN complex experimentally by means of mass andlaser spectroscopy. First experimental results will be reported besides the theoretical calculations.

[1] Loginov E., Gomez L. F., Vilesov A. F., J. Phys. Chem. A 115, 7199 (2011)[2] Ancilotto F., Lerner P. B., Cole M. W., J. Low Temp. Phys. 101, 1123 (1995)[3] Dalfovo F., Lastri A., Pricaupenko L., Stringari S., Treiner J., Phys. Rev. B 52, 1193 (1995)

81

Thu, 17:10

Combination of Fourier transform- and laser spectroscopy tofind unknown atomic energy levels

Laurentius Windholz1


Opposite to common assumptions, still not all energy levels of chemical elements are known.Thus it is quite often not possible to explain even strong spectral lines as transitions between cer-tain energy levels. For elements which nuclei possess a spin quantum number I>0, the hyperfinestructure constants can be used additional as finger print for a level. The hyperfine pattern pre-dicted for a certain level combination then can be compared with the pattern in a highly resolvedFourier transform spectrum, and the line can be classified. Lines which can not be explained ascombinations of known levels can be excited by laser light. The information gained from the ob-served hyperfine pattern (angular momenta J of the electron shell and hyperfine constants) togetherwith excitation and fluorescence wavelengths can be used to find the properties of the up to nowunknown energy levels. The existence of such level can be verified by the Fourier spectrum sincesuch level must explain other lines with respect to hyperfine pattern and center of gravity wavenumber. A computer program which allows to handle data bases for spectral lines and levels of anelement is presented.

Thu, 17:30

New energy levels of the neutral Pr atom in the IR regionBettina Gamper1, Imran Siddiqui1, Uddin Zaheer2, Laurentius Windholz1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Yanbu University College, Yanbu Industrial City 510000, P.O.box 31387, Kingdom of Saudi Arabia

With the help of the new Fourier transform spectra (FTS) of Pr [1] and with laser-inducedfluorescence (LIF) spectroscopy it was possible to find a big amount of new energy levels in thepast year [2], [3] and [4]. In the IR region we still do not have a suitable laser to perform LIF spec-troscopy. Nevertheless for some well-resolved lines, we were able to investigate their structure andhence to introduce 21 new energy levels of the neutral Pr atom. All of them have odd parity andtheir J-value differs from 1/2 to 19/2. The appearance of the line in the FTS, the small componentshave to be resolved, gives us the J-value and the hf constants could be determined by fitting thehf pattern of the investigated line. All of the newly presented atomic levels explain a lot of so farnot classified lines. As an example we discuss the line with the cg wavelength 9319.006 and the sodetermined level with an energy of 22442.185(5) cm−1, a J-value of 15/2 and a hf constant A of959(9) Mhz (the hf constant B is assumed to be zero).

[1] B.Gamper et al.; J. Phys. B. 44, 045003 (2011)[2] K.Shamim et al.; Eur. Phys. J. D 64, 209-220 (2011)[3] T.I.Syed et al.; Phys. Scr. 84, 065303 (2011)[4] Z.Uddin et al.; Journal of Physical Science and Application, in press

82

8 Solid State Physics (FKP) &Research with Neutron and Synchrotron Radia-tion (NESY)HS 15.12

Solid State Physics and Research with Neutrons and Synchrotron RadiationFestkorperphysik: Physik an Neutronen- und SynchrotronstrahlungsquellenGottfried Strasser, [email protected] Bauer, [email protected]



09:00 - 09:30 Armando RastelliElectro-elastic control of excitons insingle quantum dots

09:30 - 09:45 Roland BrunnerImaging of classical trajectories andquantum mechanical states in openquantum dots

09:45 - 10:00 Benedetta MarmiroliWhat can be obtained by bringingtogether small angle X-ray scatteringand deep X-ray lithography?

10:00 - 10:15 Rainer LechnerCore/shell profile of nanocrystals de-termined by anomalous SAXS

10:15 - 10:30 Dominik KriegnerSupercrystals formed by monodispersenanocrystals investigated by X-raydiffraction

10:30 - 10:45 Mario KeplingerInvestigations of radial and axial het-erostructured nanowires using x-raydiffraction

10:45 - 11:00 Walter PotzQuantum Dot Cavity Spin Entangle-ment at a Distance - A TheoreticalAnalysis


83



14:30 - 14:45Martin Kaltenbrunner

Anton Paar-PrizePower Supply, Generation and Storagein Stretchable Electronics

14:45 - 15:00 Christian ErtlerDisorder effects on resonant hole tun-neling transport in (Ga,Mn)As/GaAsheterostructures

15:00 - 15:15 Benjamin SticklerPrediction of room-temperature spinfiltering in (CrAs/GaAs) heterostruc-tures

15:15 - 15:30 Rene HammerDynamics of Dirac Fermions on Sur-faces of Topological Insulators




15:50 - 16:05 Peter ReiningerEnhancing the detectivity of photoniccrystal photodetectors by quality fac-tor tuning

16:05 - 16:20 Benedikt SchwarzOptimization of intersubband devicesfor dual-color emission, absorption anddetection

16:20 - 16:35 Lukas BurgstallerSubstrate emitting ring cavity quan-tum cascade lasers

16:35 - 16:50 Ronald MeiselsStudies on the Coupling of Dielectricand Plasmonic Waveguides using FEMand FDTD Simulations

16:50 - 17:20 Michael ReissnerSuperconducting properties of multi-filamentary MgB2 wires

17:20 - 17:35 Stefan Topolovec

Combining SQUID magnetometrywith in-situ cyclic voltammetry tostudy the electrochemical charging-induced variation of the magneticmoment of γ-Fe2O3 nanoparticles

17:35 - 17:50 Thomas FranoschTransport beyond Brownian Motion –Colored noise

17:50 FKP & NESY member meeting

84



09:00 - 09:15 Mattia CapriottiComparison of MOS and Schottky-barrier structure in AlGaN/GaNHEMTs

09:15 - 09:30 Alfred NeuholdInterface Morphology of an OrthogonalSoluble Polymer Transistor

09:30 - 09:45 Michael Dohr

Temperature Induced Wet-ting and Dewetting Effects ofDioctylbenzothieno-benzothiopheneon Silicon Oxide Surfaces

09:45 - 10:00 David GeistMetastable structures and phases of in-termetallics produced by severe plasticdeformation

10:00 - 10:30 Benedetta MarmiroliQuantitative analysis of liquid jetsbreakup with SAXS

10:30 - 10:45 Martin Luckabauer

Direct measurements of reversiblefree-volume formation in bulkZr56Al7Cu24Ni10Co3 glass belowthe glass transition temperature

10:45 - 11:00 Peter ParzPositron annihilation spectroscopyon LiCoO2-electrodes with differentlithium content


Friday, 21th September 2012, HS 15.1211:30 - 12:45


11:30 - 12:00 Heinz AmenitschSelf Assembly of Mesoporous Materi-als in the Gas-Phase: An in situ SADStudy

12:00 - 12:15 Markus HartmannMechanical properties of carbonnanostructures investigated by MonteCarlo simulations

12:15 - 12:30 Maria DaghoferTopologically nontrivial and nearly flatbands in multi-orbital models

12:30 - 12:45 Jorn VenderbosItinerant electrons in a 2-dimensionalspin-ice system: Kondo-Lattice modelon the checkerboard lattice

Thu, 09:00 - 11:00, HS 15.12

85

Thu, 09:00, Invited

Electro-elastic control of excitons in single quantum dotsArmando Rastelli1,2, Rinaldo Trotta1,2, Eugenio Zallo2, Paola Atkinson2, Oliver Schmidt2

1Johannes Kepler Universitat Linz, Altenberger Straße 69, 4040 Linz, Austria2IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

Optically active semiconductor quantum dots (QDs) can be made as epitaxial nanoinclusions ofa low energy bandgap material in a matrix with larger energy bandgap. Many recent experimentshave demonstrated that these QDs are excellent quantum emitters, which can be used as sources oftriggered single photons, indistinguishable photons and polarization entangled photon pairs. Thestructural properties of self-assembled QDs are affected by unavoidable fluctuations, which makeit difficult to obtain QDs with electronic and optical properties which meet the - sometimes verystringent - requirements for their use in advanced quantum optics experiments. Post-growth tech-niques are therefore needed to fine-tune the optical properties of QDs. In this talk we will discussQD-based devices in which the semiconductor structures are integrated on top of piezoelectric ac-tuators made of PMN-PT. This combination allows us to study in detail the effects produced byvariable strains (up to about 0.3%) on the excitonic emission of single QDs and to manipulatereversibly and in a broad range the excitonic emission of single dots. In particular, by using diode-like nanomembranes we can simultaneously use elastic deformation and electric fields to controlthe electronic structure of QDs. This allows us e.g. to achieve independent control of emission en-ergy and charge-state of a QD and to realize wavelength-tunable single-QD light-emitting diodes.Possible future extensions and applications of this technology will be discussed.

Thu, 09:30

Imaging of classical trajectories and quantum mechanicalstates in open quantum dots

Roland Brunner1, Ronald Meisels1, Nobuyuki Aoki2, Yuichi Ochiai2, Richard Akis3, Adam Burke4,David Ferry3

1Montanuniversitat Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria2Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan

3Arizona State University, P.O. Box 9309, Tempe, AZ 85287-9309, USA4University of New South Wales, Sydney, NSW 2052, Australia

In this work, we show classical and quantum mechanical simulations as well as scanning gatemicroscopy (SGM) to probe the ballistic motion of electrons within an open GaAs/AlGaAs quan-tum dot (QD). SGM, in combination with transport measurements, can provide an interestingtool to image the motion of electrons in quantum systems [1]. Recently, it has been theoreticallyargued for an open QD that, due to the induced perturbation of the SGM tip the imaging of theoriginal open QD states is ambiguous [2]. However in this theoretical approach a system with ahard wall potential was used. Our model calculations are performed by using a soft-wall as op-posed to a hard-wall potential. This potential is obtained from fully self-consistent calculations.From the classical and quantum mechanical simulations we are able to extract the electron trajec-tories and probability density, respectively. Conductance maps are recorded by using SGM. Here,a biased tip in a cryogenic SGM is scanned over the open quantum dot while a magnetic field isapplied. We show that, for specific magnetic fields, the measured conductance images resemble theclassical transmitted and backscattered trajectories and their quantum mechanical analogue [3].The demonstrated direct imaging technique is essential for the fundamental understanding of wavefunction scarring and quantum decoherence theory.

[1] M. A. Topinka et al., Science 289, 2323 (2000).[2] M. Mendoza and P.A. Schulz, Phys. Rev. B 71, 245303 (2005).[3] N. Aoki, R. Brunner et al., Phys. Rev. Lett. 108, 136804 (2012).

86

Thu, 09:45

What can be obtained by bringing together small angle X-rayscattering and deep X-ray lithography?

Benedetta Marmiroli1, Fernando Cacho-Nerin1, Barbara Sartori1, Paolo Falcaro2, Luca Malfatti3,Marco Faustini4, Stefano Costacurta5, David Grosso4, Plinio Innocenzi3, Heinz Amenitsch1

1Osterreichische Akademie der Wissenschaft, Schmiedlstrasse 6, 8042 Graz, Austria2CSIRO, Gate 5 Normanby Rd, Clayton VIC 3168, Australia

3LMNT, Universita di Sassari, Palazzo Pou Salit, Piazza Duomo, 6 - 07041 Alghero (SS), Italy4Universit Pierre et Marie Curie, 4 place Jussieu, Tour 54, E.5 Couloir 54-55, 75252 Paris Cedex 05, France

5CIVEN, Via delle Industrie 5, Torre Hammon, 30175 Venezia-Marghera, Italy

Micro-nanotechnology has melted away the borders between material science and biology. Infact, the miniaturization of chemical and biological assays, promoted by micro-nanofluidics, requiresboth a careful selection of the fabrication methods and the development of tailored materials forthe specific applications. As a consequence, interdisciplinarity is becoming fundamental also in thecombination of microfabrication and characterization techniques both aimed at the construction ofnew devices and at the development of novel materials for chemistry and biology applications. Inthis communication, we want to underline the advantages obtainable by combining two techniques:Deep X-ray Lithography (DXRL) for microfabrication and Small and Wide Angle X-ray Scattering(SAXS/WAXS) for investigation. On one hand DXRL makes it possible for SAXS to improve timeresolution and create new sample environments. On the other hand SAXS permits the investigationof the nanostructural morphology of the microstructures fabricated by DXRL in order to tune themorphology for specific applications like nanosensors and biosensors or to determine the effect ofirradiation on new materials. Examples will be presented to highlight both. First, microdevicesfabricated for time resolved experiments of fast biological and chemical reactions, or for the study ofthe effect of confinement on crystal growth will be discussed. Then, the combination of bottom-upand top-down approaches for the development of new functionalized materials for which character-ization with SAXS/WAXS is fundamental will be described.

Thu, 10:00

Core/shell profile of nanocrystals determined by anomalousSAXS

Rainer Lechner1, Gerhard Fritz-Popovski1, Maksym Yarema2, Wolfgang Heiss3, Oskar Paris1

1Montanuniversitat Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria2Swiss Federal Laboratories for Material Science and Technology, Uberlandstrasse 129, 8600 Dubendorf, Switzerland

3Johannes Kepler Universitat Linz, Altenberger Straße 69, 4040 Linz, Austria

The infrared emission of lead chalcogenide nanocrystals (NCs) can be drastically increased sta-bilising the core with a hard protective shell [1]. In contrast to a shell growth on top of a core [2],we investigate in this study the CdS-shell growth on PbS NCs driven by Cd for Pb cation exchange[1]. We perform anomalous SAXS experiments at the synchrotrons HZB-BessyII and ESRF. Tun-ing the x-ray energy below the Pb-edge allows to record ASAXS spectra, where the contributionof Pb to the scattering signal is varied. This allows resolving the total electron density and thePb-atom density inside the core/shell NCs independently. We derive the following results: Duringthe exchange process applied to PbS spheres, the core shrinks, the CdS shell thickness increases,while the outer diameter as well as the size distribution remains constant. The CdS shell thicknessranges from 0.9 nm for 10 nm large PbS NCs to even 2 nm for 5 nm small NCs. The final shellthickness scales with 1/D of the sphere diameter, related to an increased surface to volume ratiofor the smaller NCs. For the thin CdS shells we found no reaming Pb within the shell, whereas forthick shells we detect 2 Pb atoms per cubic-nm within the shell.

[1] H. Zhao, M. Chaker, N. Wu and D. Ma, J. Mater. Chem., 21, (2011)[2] M. Yarema, S. Pichler, M. Sytnyk, R. Seyrkammer, R.T. Lechner, et al., ACS Nano 5, (2011)

87

Thu, 10:15

Supercrystals formed by monodisperse nanocrystalsinvestigated by X-ray diffraction

Dominik Kriegner1, Maksym Yarema2, Tanja Etzelstorfer1, Mario Keplinger1, Mykhailo Sytnyk1,

Wolfgang Heiss1, Maksym Kovalenko2, Julian Stangl1

1Johannes Kepler Universitat Linz, Altenberger Straße 69, 4040 Linz, Austria2ETH Zurich, Department of Chemistry and Applied Biosciences, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland

Colloidal nanocrystals are subject of intense research because of their high potential for appli-cations in electronic, magnetic and optical devices. Furthermore they show a high tendency to formordered two and three-dimensional superstructures (“supercrystals”). The precise ordering in thosesupercrystals affects the electronic coupling between the individual nanocrystals and it was shownto lead to new collective properties. These properties are related to, and hence strongly affectedby the degree of ordering obtained in the supercrystals, which in turn depends on nanocrystal size,the capping ligands and chemical species of chosen nanocrystals, as well as the monodispersity ofthe used nanocrystal batch. Thus, quantifying the degree of ordering and perfectness of super-crystals is of major interest, in order to enable a quantitative correlation between ordering andthe ordering-dependent physical properties. To judge the quality of self-assembly obtained in 3Dnanocrystal superlattices, we use X-ray diffraction, applied to individual supercrystallites. Thesupercrystals have typical sizes of 10µm, whereas the nanocrystals are below 20nm in diameter.While for two-dimensional arrays of self-assembled nanocrystals, ordering can be quantified by in-specting electron microscope images, for faceted 3D nanocrystal supercrystals, much more effortshave to be undertaken to obtain characteristic numbers, which allow to assess the degree of orderingobtained by the self assembly process. 3D reciprocal space maps are recorded at a synchrotronsource using a micrometer sized X-ray beam, from which we find that the quality of ordering isstrongly anisotropic.

Thu, 10:30

Investigations of radial and axial heterostructured nanowiresusing x-ray diffraction

Mario Keplinger1, Bernhard Mandl1, Maria Messing2, Dominik Kriegner1, Julian Stangl1,

Vaclav Holy3

1Johannes Kepler Universitat Linz, Altenberger Straße 69, 4040 Linz, Austria2Lund University, S-22 100 Lund, Sweden

3Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic

The unique electronic, optical, and structural properties of semiconductor nanowires (NWs)allow the fabrication of suitable building blocks for future nanoelectronic and nanophotonic devices.Such applications require complex NW structures with either axial or radial NW heterostructuresto provide for carrier confinement and/or for the waveguiding of light. Therefore we investigatedsamples with InAs1-x Px heterostructured NWs. These heterostructured NWs consist of an InAscore with an InAs1-x Px shell and heterosegment on top. The structural and chemical propertieswere investigated depending on the growth conditions. For one series with varied arsine/phosphineflow, and one with varied growth temperature, the average chemical composition, i.e. the phospho-rus content, the strain, and the dimensions were deduced using a combination of scanning electronmicroscopy (SEM), X-ray energy dispersive spectroscopy, and X-ray diffraction (XRD). The XRDdata evaluation was done by calculating the strain distribution in a NW using finite element sim-ulations. From this simulations the diffusely scattered intensity distribution was then calculatedfor a NW ensemble with a simple Monte Carlo method to account for statistical variations of theNW properties. A dependency of the P to As ratio in the hetero-segment on the arsine/phosphineprecursor ratio was found with a proportionality factor of 0.75, whereas the variation of the growthtemperature gave no variation of the chemical composition, but a change of the NWs aspect ratio.

88

Thu, 10:45

Quantum Dot Cavity Spin Entanglement at a Distance - ATheoretical Analysis

Walter Potz1


Measurement of conditional Faraday rotation has recently been proposed for entanglement gen-eration at a distance.[1-3] In this talk we present a theoretical analysis of entanglement formationat a distance between two electron spins, each sitting in one of two “distant” quantum dot cavities.Entanglement is induced by measuring the conditional Faraday rotation of a non–resonant laserpulse which has propagated through the two cavities. The basis for this scheme are two “identical”scatterers, such as an atom or a quantum dot, where each has two initial states, whereby only oneof them is optically active, for example, by dipole selection rules. Here we investigate one–sidedcavities which avoid unintentional measurement in the reflected beam.[4] Frequency “sweet–spots”are identified for which, in spite of dissipative action, good fidelity entanglement generation shouldbe possible. We also predict that monitoring of the Faraday rotation allows the detection of sin-gle spin flips, similar to single non–demolition photo-emission monitoring in atom quantum cavitysystems.[5] The possibility of studying entanglement death and revival in this system is discussed.

[1] T. D. Ladd et al., New Journal of Physics 8, 184 (2006).[2] J. Grond, W. Potz, and A. Imamoglu, Phys. Rev. B 77, 165307 (2008).[3] W. Potz, Physical Review B 77, 035310 (2008).[4] W. Potz, J. Comp. Electr., Volume 8 (1), 25-28 (2009).[5] M. Brune et al., Phys. Rev. Lett. 101, 240402 (2008).


89

Thu, 14:30 - 15:30, HS 15.12

Thu, 14:30, Anton Paar-Prize Winner

Power Supply, Generation and Storage in StretchableElectronics

Martin Kaltenbrunner1

1Johannes Kepler Universitat Linz, Altenberger Straße 69, 4040 Linz, Austria

Talk of the Anton Paar-Prize Winner.

Thu, 14:45

Disorder effects on resonant hole tunneling transport in(Ga,Mn)As/GaAs heterostructures

Christian Ertler1, Walter Potz1


Recent experiments on heterostructures comprising (Ga,Mn)As quantum wells [1] have evokedstrong debates about the near absence of ferromagnetic order observed in these structures [2]. Here,we present a theoretical examination of these experimental results, studying the self-consistent in-terplay between ferromagnetic order, structural defects, and the hole tunnel current [3]. Thehole band structure is described by a four band Kohn-Luttinger Hamiltonian and the transportcharacteristics are obtained within the non-equilibrium Green’s function approach. We show thatdisorder has a strong influence on the current-voltage (IV) characteristics in efficiently reducing oreven washing out negative differential conductance, as found in experiment. The hole density inthe quantum well is established through (tunneling) transport from the p-doped GaAs leads. Wefind that, for the Be lead doping levels used in experiment, the resulting spin density polarizationin the quantum well only produces an exchange splitting of the order of a few meV, comparableto the experimental findings. We predict that the ferromagnetic order in the (Ga,Mn)As quantumwell tends to be completely destroyed under resonance bias condition. This should lead to a char-acteristic bias-dependence of the spin-polarization (bias anomaly) of the tunnel current, availableto experimental detection.

Supported by FWF P21289-N16.

[1] S. Ohya, K. Takata and M. Tanaka, Nature Physics, 7, 342 (2011).[2] T. Dietl and D. Sztenkiel, arXiv:1102.3267 (2011).[3] C. Ertler and W. Potz, Phys. Rev. B 84, 165309 (2011).

90

Thu, 15:00

Prediction of room-temperature spin filtering in(CrAs/GaAs) heterostructures

Benjamin Stickler1, Christian Ertler1, Liviu Chioncel2, Enrico Arrigoni3, Walter Potz1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Zentrum fur Elektronische Korrelationen und Magnetismus, Universitat Augsburg, 86135 Augsburg, Germany


Half-metallic materials are of profound interest in spintronic applications since, by definition,their density of states at the Fermi energy is 100 % spin polarized. Recent experiments as well asab-initio calculations suggest that CrAs, grown epitaxially in the fcc structure on top of GaAs, issuch a halfmetallic ferromagnet with a Curie temperature well above room temperature [1,2]. Wepresent theoretical results, which suggest that spin-filtering in CrAs/GaAs heterostructures at roomtemperature could indeed be realized. Our theoretical approach consists of three crucial steps: Ina first step we determine the spin-polarized band structure of lattice matched fcc bulk CrAs and a(GaAs)6/(CrAs)6 supercell. From these calculations we determine the band offset between the twomaterials as well as their bulk electronic structure. Within the second step we map the electronicstructure of the bulk materials onto an effective 20-orbtial sp3d5s* nearest neighbor tight-binding(TB) model. In a third step we calculate current-voltage (IV) characteristics for heterostructuresconsisting of thin layers of CrAs embedded in a GaAs environment. The characteristics are de-termined within the non-equilibrium Green’s function formalism. The resulting IV characteristicsprovide an experimentally accessible fingerprint of the electronic structure of fcc CrAs and indicatethat room temperature spin filtering should indeed be realizable in such systems. (Supported byFWF P221290-N16)

[1] H. Akinaga, T. Manago, M. Shirai, Jpn. J. Appl. Phys., 39 (2000)[2] L. Chioncel et al. Phys. Rev. B, 83 (2011)

Thu, 15:15

Dynamics of Dirac Fermions on Surfaces of TopologicalInsulators

Rene Hammer1, Christian Ertler1, Walter Potz1


Topologically protected states may form at the surface of insulators with strong spin-orbit in-teraction[1]. Near the Kramer’s points, the electronic states can be mapped upon a mass-less 2+1Dirac fermion Hamiltonian and the effective-mass term can be controlled by an external magneticfield (breaking time-reversal symmetry). In this talk we present some of our recent results froma theoretical study of the dynamics of 1+1 and 2+1 Dirac fermions simulated numerically on alattice. For 1+1 dimensions we present and demonstrate perfect absorbing boundary conditionsusing algorithms which avoid fermion doubling. In 2+1 dimensions we present absorbing boundaryconditions obtained from an imaginary potential in the asymptotic space regions[2]. For numericalexamples we study several physical processes: wave packet propagation at a simple Klein step, aquantum interferometer[2], and a superlens realization.

[1] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045 (2010).[2] Ren Hammer, Christian Ertler, and Walter Potz, arXiv:1205.6941 (2012)

91


Thu, 15:50 - 17:35, HS 15.12

Thu, 15:50

Enhancing the detectivity of photonic crystal photodetectorsby quality factor tuning

Peter Reininger1, Stefan Kalchmair1, Roman Gansch1, Aaron Maxwell Andrews1, Hermann Detz1,

Tobias Zederbauer1, Werner Schrenk1, Gottfried Strasser1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria

An important figure of merit of photodetectors is the detectivity. A quantum well infraredphotodetector (QWIP) has an inherent limitation to the detectivity at higher temperatures (aboveTBLIP), because an increase of the responsivity by higher doping increases the noise by about thesame amount. Therefore, both effects cancel each other out. Another approach is to use a photoniccrystal slab (PCS) as a resonant cavity in conjunction with a reduced doping concentration in thequantum wells. We have shown, that the noise due to dark current can be reduced significantly,while the high lifetime of photons in the PCS maintains a high responsivity. We present a PCS fab-ricated from a QWIP material. Under Globar illumination, an increase of the maximum operationtemperature from around 110K for a standard QWIP up to 200K for a low-doped PCS-QWIP witha peak absorption at λ = 8µm was observed. The combined effect of responsivity enhancementand dark current noise reduction results in an enhanced specific detectivity D* of up to 20 times.

Thu, 16:05

Optimization of intersubband devices for dual-color emission,absorption and detection

Benedikt Schwarz1, Peter Reininger1, Oskar Baumgartner2, Zlatan Stanohevic2, Hans Kosina2,Gottfried Strasser1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria2Vienna University of Technology, Gußhausstrasse 27-29, 1040 Vienna, Austria

Quantum cascade lasers (QCL) and detectors (QCD) are powerful mid-infrared devices. AQCL can also act as a photovoltaic detector, but normally at a significant lower wavelength thanthe laser. Thus quantum cascade structures are commonly designed as either lasers or detectors.We have designed a dual wavelength quantum cascade structure that can act as coherent source andphotovoltaic detector at the same wavelength. As a step towards monolithic integrated photoniccircuits, such multipurpose devices open up new possibilities for on-chip applications by emitting,absorbing and detecting light on the same chip. Apart from typical real world applications, likechemical sensing, spectroscopy and free space communication, it can be used to study optical cou-plings, interaction of light and matter, as well as non-linear effects within one chip. Due to itscomplexity, such a device structure requires a careful quantum design to maximize performance,while matching the designed wavelength for both laser and detector operation. When a certainvoltage is applied, the structure acts as a dual wavelength laser. At zero bias it acts as a photo-voltaic detector or a. In this case, the injector states form a phonon ladder leading to a built-inelectric field. After optical excitation the electrons can scatter via this phonon ladder to the lowerlevel of the next period. The design fine tuning is done by an optimization algorithm based on ahigh efficient semi-classical Monte-Carlo quantum cascade simulator.

92

Thu, 16:20

Substrate emitting ring cavity quantum cascade lasersLukas Burgstaller1, Clemens Schwarzer1, Sang Il Ahn1, Werner Schrenk1, William Charles2,

Claire Gmachl3, Strasser Gottfried1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria2Phononic Devices, Inc., Raleigh, North Carolina 27606, USA

3Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA

Quantum cascade lasers (QCLs) evolved to versatile and reliable light sources in the mid-infrared (MIR) and terahertz (THz) spectral region. Recently, our group reported the ring cavitysurface emitting QCL. The ring-type resonator, in combination with a second order distributedfeedback grating (DFB) grating provides collimated beam profiles, along with robust single-modeemission. DFB gratings also diffract a certain amount of light towards the substrate. Within thiswork we perform investigations regarding the emission direction of ring-QCLs. A variation of thegrating duty cycle (GDC) is performed to obtain an enhancement of the substrate emitted opticalpower. All devices showed single-mode operation at frequencies around 1296 /cm. Peak opticalpower values of 16.6 mW for surface emission and 9.25 mW for substrate emission were measured.When the GDC is not optimized for surface emission (around 70% ), a far greater amount of lightis emitted through the substrate. Maximum values for substrate emission are found for GDCsaround 56%. This agrees very well with the simulation results. When accounting for the substrateabsorption and the transmission coefficient at the substrate-air interface, it is demonstrated thatthe whispering gallery modes are predominantly diffracted towards the substrate. The authorsacknowledge the support by the Austrian projects IR-ON (FWF: F2503-N17) and PLATON, theGMe and MIRTHE (NSF-ERC, EEC 0540832).

Thu, 16:35

Studies on the Coupling of Dielectric and PlasmonicWaveguides using FEM and FDTD Simulations

Ronald Meisels1, Markus Humer2, Oleksandr Glushko1, Roland Brunner1, Thomas Fromherz2

1Montanuniversitat Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria2Johannes Kepler Universitat Linz, Altenberger Straße 69, 4040 Linz, Austria

An important goal for optimizing the transfer of light into and out of silicon based waveguidesfor integrated optics is the reduction of the footprint of the device on a chip. Therefore a hybriddielectric/plasmonic coupling structure [1] is studied. The plasmonic modes of a gold strip of sub-skin-depth thickness couple symmetrically and asymmetrically to form long range (LRSPP) andshort range surface plasmon polaritons (SRSPP) respectively. The dimensions of the gold strip aretuned to support effective-index-matching of the SRSPP mode and the fundamental mode of a SoI(Silicon on Insulator) based waveguide. Bringing the gold strip close to the dielectric waveguideresults in a coupling of the individual modes forming two hybrid SRSPP/dielectric modes A and Bwhich are nondegenerate, where their superpositions (A+B and A-B) are concentrated in the metaland in the dielectric, respectively. In accordance with coupled mode theory [2] optical power istransferred from the metal strip to the dielectric waveguide (or vice versa). The field distributionsand phase velocities of the different structures are determined by the finite element method (FEM).The FDTD method is used to verify the coupling length. Because the SRSPP mode is so stronglyconfined to the metal strip very short coupling lengths were simulated, to use this device as anultra-short coupler between plasmonic and dielectric structures.

[1] Wan et al., Appl.Phy.Lett. 94, 141104 (2009)[2] Yariv & Yeh, Optical Waves in Crystals (2002), ISBN: 978-0471430810

93

Thu, 16:50, Invited

Superconducting properties of multi-filamentary MgB2 wiresMichael Reissner1, Stefan Sorta1, Lukas Bulla1, Tibor Melisek2, Pavol Kovac2

1Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria2Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava, Slovak Republic

Many efforts are underway to produce multi-filamentary wires of MgB2, where the super-conducting filaments are embedded in good conducting material. Unfortunately strong chemicalreactions between MgB2 and Cu deteriorate superconducting properties strongly. Therefore barriersheaths between both materials are necessary. For these Nb and Ti are found to be useable. Theimportant question is, how superconducting properties depend on the reduction of both filamentdiameter and barrier thickness. In this work we report on magnetic investigation of a series of MgB2wires, with nineteen filaments. All samples were prepared in the same way, but with filament diam-eters between 58.8 and 17.7 µm. With decreasing filament diameter the width of superconductingtransition increases, although superconducting transition itself is not changed. Critical current den-sity and irreversibility line also decrease. From magnetic relaxation measurements mean effectiveactivation energies U are determined. They are also decreasing with decreasing filament diameter.The temperature dependence of U points to the existence of a pinning energy distribution, whichbroadens with decreasing filament diameter.

Thu, 17:20

Combining SQUID magnetometry with in-situ cyclicvoltammetry to study the electrochemical charging-inducedvariation of the magnetic moment of γ-Fe2O3 nanoparticles

Stefan Topolovec1, Heinz Krenn2, Roland Wurschum1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2University of Graz, Universitatsplatz 5, 8010 Graz, Austria

Electrical tuning of magnetic properties has emerged as an important topic of materials re-search in the last years. Recently, we could demonstrate that the magnetic moment of γ-Fe2O3

nanoparticles can be tuned reversibly by electrochemical charging [1]. In order to study the elec-trochemical processes taking place and their influence on the magnetic moment in more detail, wehave now designed a special electrochemical cell, allowing the recording of cyclic voltammogramsin-situ in a SQUID magnetometer. To charge the insulating γ-Fe2O3 nanoparticles, which wereprepared by microwave plasma synthesis, a porous pellet of γ-Fe2O3 nanoparticles and Pt nanopar-ticles was formed. The charging of the pellet was performed in an aqueous electrolyte of 1M KOH.Reversible variations of the magnetic moment of γ-Fe2O3 nanoparticles up to several percent couldbe achieved. From the combined measurements of cyclic voltammograms and the magnetic momentit became obvious, that the charging coefficient s = ∆m/∆Q significantly depend on the examinedpotential range. The variation of the nanoparticles moment is considered to arise from reversibleelectrochemically induced reactions at the surface of the γ-Fe2O3 nanoparticles. In addition, charg-ing induced variations of the magnetic surface anisotropy may play a role. Financial support bythe FWF Austrian Science Fund is appreciated (project S10405-N16).

[1] T. Traußnig et al., Phys. Status Solidi - Rapid Res. Lett. 5 (2011) 150.

94

Thu, 17:35

Transport beyond Brownian Motion – Colored noiseThomas Franosch1, Matthias Grimm1, Maxim Belushkin1, Flavio Mor1, Giuseppe Foffi1,

Laszlo Forro1, Sylvia Jeney1

1Friedrich-Alexander-Universitat Erlangen-Nurnberg, Staudtstrasse 7, 91058 Erlangen, Germany

Brownian motion is one of the pillars of statistical physics with applications ranging from as-trophysics to biological physics. The theoretical foundation is well understood since Einstein andSmoluchowski introduced a probabilistic interpretation to derive diffusion as a macroscopic law. Inmodern language, the diffusion propagator follows from the central limit theorem. Although themean-square displacement is dominated by the linear increase for long times and finite diffusionconstant, persistent correlation underlying the transport may be unraveled by studying the corre-sponding velocity autocorrelation functions (VACF). I will discuss recent theoretical, simulation,and experimental advances highlighting power-law tails in the VACF which correspond to a coloredcomponent in the power spectrum of the force correlator due to hydrodynamic backflow [1,2].

[1] T. Franosch et al., Nature 478, 85-88 (2011)[2] S. Jeney et al., Phys. Rev. Lett. 100, 240604 (2008)

Thu, 17:50: FKP & NESY member meeting

Fri, 09:00 - 11:00, HS 15.12

Fri, 09:00

Comparison of MOS and Schottky-barrier structure inAlGaN/GaN HEMTs

Mattia Capriotti1, Alexander Alexewicz1, Anil Parlar1, Frank Brunner2, Aaron Maxwell Andrews1,

Dionyz Pogany1, Gottfried Strasser1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria2Ferdinand Braun Institut, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany

GaN high electron mobility transistors (HEMTs) for power switching and digital applicationsrequire a low gate leakage current (Ig) and a high threshold voltage, allowing normally-off opera-tion, but no common solution has been presented yet. It is known that engineering fixed charges atthe barrier/oxide interface creates both normally-off and normally-on devices with the same het-erostructure. In this work, we present a comparison between metal oxide semiconductors (MOS)and Schottky-barrier (SB) AlGaN/GaN HEMTs. We investigate devices with a heterostructureconsisting of a 2 mm thick GaN buffer, 16 nm Al0:24Ga0:76N barrier and a 3 nm GaN:Si cap layer.In the MOSHEMT devices, after recessing the GaN cap layer below the gate, ZrO2 layers of 10and 15 nm are deposited by atomic layer deposition on the barrier. Depositions were performedat 150◦C and at 2000◦C. In SB devices the Ni/Au gate metallization is deposited directly on thebarrier. The SB samples show an exponential increase of Ig for a forward gate bias Vgf > 3 V,while the inclusion of a ZrO2 interlayer allows to increase the Vgf up to 8 V for the same Ig. Lowvalues of Ig at a high gate bias indicate better gate oxide structural properties. Contrary to SBdevices, the MOSHEMTs exhibit large hysteresis in the transfer characteristics, indicating chargesat the interface ( 1012cm−2).

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Fri, 09:15

Interface Morphology of an Orthogonal Soluble PolymerTransistor

Alfred Neuhold1, Hannes Brandner1, Simon Ausserlechner1, Stefan Lorbek2, Markus Neuschitzer1,Egbert Zojer1, Christian Teichert2, Roland Resel1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Montanuniversitat Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria

Understanding the interfacial properties of an organic multilayer arrangement is crucial whenintending to use such structures in electronic devices. In this work we focus on the interfacemorphology of orthogonal soluble polymers in a solution processed polymer field effect transistor(PTFT). A water soluble poly-(4-styrenesulfonic acid) (PSSA) was solution deposited as a layer tomodify the properties of the gate dielectric and on top of it the poly-(3-hexylthiophene) (P3HT)was spin cast as organic semiconducting polymer. Two relatively a-polar solvents (either chlo-roform or toluene), were used for the P3HT deposition. Gracing incidence X-ray diffraction wasused to determine the orientation of the P3HT crystallites, which were face-on aligned for P3HTdissolved in chloroform and edge-on aligned for P3HT dissolved in toluene. The surface and inter-face roughness was investigated by X-ray reflectivity experiments and the surface roughness wascross-checked by atomic force microscopy. First experiments regarding the performance of theselayers in thin-film transistors were conducted and revealed a one order of magnitude higher chargecarrier mobility when spin-coating the P3HT film from toluene compared to the device for whichchloroform has been used as solvent for P3HT deposition. This is assigned to the better definedPSSA/P3HT(toluene) interface morphology.

Fri, 09:30

Temperature Induced Wetting and Dewetting Effects ofDioctylbenzothieno-benzothiophene on Silicon Oxide Surfaces

Michael Dohr1, Oliver Werzer2, Quan Shen3, Roland Resel1, Christian Teichert3, Yves Geerts4,Michele Sferrazza4, Ingo Salzmann5

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2University of Graz, Humboldtstraße 46/I, 8010 Graz, Austria

3Montanuniversitat Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria4Universite Libre de Bruxelles, CP 206/01 Campus de la Plaine, 1050 Bruxelles, Belgium

5Humboldt-Universitat zu Berlin, Unter den Linden 6, 10099 Berlin, Germany

The excellent performance of the molecule dioctyl-benzothieno-benzothiophene (C8-BTBT) inorganic thin film transistors is strongly influenced by heat treatment. Spin coating of the film atelevated temperatures (within the liquid-crystalline state), leads to an increase in charge carriermobilities up to 3 cm2/V s. The structural properties of C8-BTBT thin films are investigated as afunction of temperature in terms of crystallographic properties and morphology. Spatially resolvedmicroscopic methods (AFM and optical microscopy) as well as integral characterisation methods(Grazing incidence x-ray scattering, x-ray reflectivity) are used. The disordered monolayer film(thickness 2.4 nm) remains unstable after the spin coating process. With increasing temperatures,dewetting of the monolayer is observed by the formation of crystalline islands with an average heightof about 15nm. Approaching the transition temperature to the smectic state, at a temperature of90◦C, re-wetting is observed and a monolayer is formed on the substrate surface. This monolayer(thickness 2.9 nm) remains stable in the liquid crystalline state as well as after cooling back to roomtemperature. Also multilayer films show pronounced dewetting during heating by the formation ofhuge crystalline islands with a lateral size in the µm range. At 105◦C a monolayer (thickness 2.9nm), at 108◦C a bilayer and at 115◦C a triple layer has developed. Decreasing temperatures revealthe reversibility of the layer-by-layer formation. All found layered structures can be stabilized byrapid cooling.

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Fri, 09:45

Metastable structures and phases of intermetallics producedby severe plastic deformation

David Geist1, Christoph Gammer1, Peter Karnthaler1, Christian Rentenberger1

1University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria

Metastable solid structures and phases such as nanostructured or amorphous phases are ofgeneral high scientific and technological interest since they often exhibit properties different fromtheir crystalline, coarse-grained counterparts. In order to obtain metastable structures with anincreased free energy different methods can be applied. In the last decade methods of severe plasticdeformation were established to produce bulk materials comprising metastable phases. In this workwe show the structural analysis of metastable structures and phases on different length scales usingscanning (SEM) and transmission electron microscopy (TEM) methods. The metastable struc-tures were produced by high-pressure torsion of L12 long-range ordered intermetallic alloys (Ni3Al,Zr3Al, Co3Ti) based on the fcc lattice. The SEM and TEM analyses show that the metastablestructures evolve heterogeneously during deformation [1]. Depending on the type of lattice defectsinduced by deformation different saturation structures are produced: a nanocrystalline structureshowing the loss of chemical long-range order (Ni3Al) or an amorphous one. TEM methods revealthat in Zr3Al the amorphous phase contains residual nanograins of the initial phases whereas inCo3Ti devitrified nanocrystals of a structure different to the initial one are embedded in the amor-phous phase. In the latter case devitrification occurs in the course of deformation of the amorphousphase.

[1] D. Geist, C. Rentenberger, H.P. Karnthaler. Acta Mater. 59 (2011) 4578.

This work was supported by the Austrian Science Fund (FWF):[P22440]. The authors acknowledgethe use of the SEM of the “Faculty Center for Nanostructure Research”.

Fri, 10:00, Invited

Quantitative analysis of liquid jets breakup with SAXSBenedetta Marmiroli1, Fernando Cacho-Nerin1, Barbara Sartori1, Javier Perez2, Heinz Amenitsch1

1Osterreichische Akademie der Wissenschaft, Schmiedlstrasse 6, 8042 Graz, Austria2Synchrotron SOLEIL, L’Orme des Merisiers BP 48 Saint-Aubin, 91192 Gif sur Yvette Cedex, France

The breakup of liquid jets represents a wide area of research in the field of multiphase flows,fully justified by their wide presence both in industrial and in scientific applications. Moreover,the recent development of microfluidic systems has raised great interest in understanding the flowsin small spatial dimensions. Such interest has been further increased due to the evolution of freeelectron lasers and the consequent need to develop new, high throughput techniques to charac-terize biological macromolecules. Jet instability has been widely described both theoretically andby performing sumulations, however there is still need to have accurate sets of experimental data.In fact most of them are based on light scattering which is disturbed by reflection, absorptionand multiple scattering of droplets and air interface morphology, and on camera imaging which islimited by the dimension of the phenomena that can be seen. In the present communication wewant to show the potentiality of synchrotron SAXS in providing quantitative information on thedynamics of liquid jets at the nanoscale. To this purpose, we have investigated free liquid jets inair with circular nozzle geometry of different diameters (450µm-100µm), flow rates (2-10 ml/min),and solvents (water, ethanol, isopropanol and their mixtures). We determined their time depen-dent morphology and their breakup length in the Rayleigh and first wind-induced regimes. Theresulting data are considered as basis for the use of free jet micromixers to examine the evolutionof chemical and biological reactions by SAXS.

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Fri, 10:30

Direct measurements of reversible free-volume formation inbulk Zr56Al7Cu24Ni10Co3 glass below the glass transition

temperatureMartin Luckabauer1, Rainer Wunderlich2, Hans-Jorg Fecht2, Wolfgang Sprengel1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Universitat Ulm, Albert-Einstein-Allee 47, 89081 Ulm, Germany

Most models regarding the glass transition are based on information obtained from the su-percooled liquid state, either by experiment or by simulation. The slowing down of molecular oratomic motion occurring at the glass transition makes the kinetics difficult to access for commonmeasurement techniques at lower temperatures. However, possible changes around Tg regardingthe structural dynamics are believed to yield key parameters in understanding the glass transition.We report the measurement of thermally activated reversible formation and disappearance of freevolume in bulk Zr56Al7Cu24Ni10Co3 glass by means of high-resolution laser dilatometry in thelower temperature regime around the glass transition. The measurement technique involving a2-beam Michelson laser-interferometer is contactless and allows access to time constants of up to1 × 106 s. From isothermal length change measurements at different temperatures after fast tem-perature changes the underlying atomic processes were studied. According to a first analysis thebehavior can be described by an Arrhenius relation with high activation energy. Financial supportby the Austrian Science Fund (FWF) is appreciated (project P22645-N20).

Fri, 10:45

Positron annihilation spectroscopy on LiCoO2-electrodeswith different lithium content

Peter Parz1, Werner Puff1, Roland Wurschum1, Bernd Fuchsbichler2, Stefan Koller2

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2VARTA Micro Innovation GmbH, Stremayrgasse 9, 8010 Graz, Austria

LiCoO2 is widely used in Li-ion battery systems as an intercalation electrode material. Re-versible charge/discharge cycling of LiCoO2 is only possible up to 50% of the available Li-ions,further removal of Li-ions drastically reduces the capacity and cycle stability. The extraction oflithium ions is expected to leave open volumes, which should act as positron traps. Therefore,Positron Annihilation Lifetime Spectroscopy (PALS) was applied on a LiCoO2 electrode material,to monitor the changes of the mean positron lifetime upon different discharge levels. The elec-trodes consist of LiCoO2 with addition of carbon for electrical conductivity and a polymer binder.These electrodes were then discharged to LixCoO2, with x = 1, 0.8, 0.7, 0.6, 0.55, 0.5, 0.4 and 0.3.The electrodes were disassembled, rinsed and dried in argon atmosphere and ex-situ investigatedby positron lifetime spectroscopy. For a lithium content of the LixCoO2 of x = 1 - 0.6 a linearincrease of the mean positron lifetime could be monitored, which can be attributed to an increasein size and concentration of the free volume, due to missing lithium ions and in addition to a mon-oclinic distortion of the hexagonal structure, due to Coulomb repulsion of the remaining negativelycharged CoO2 groups. Upon further removal of lithium x = 0.4 - 0.3 a strong deviation from thelinear increase of the mean positron lifetime could be monitored, which can be attributed to thedissolution of CoO2 from the electrode.

98


Fri, 11:30 - 13:00, HS 15.12

Fri, 11:30, Invited

Self Assembly of Mesoporous Materials in the Gas-Phase: Anin situ SAD Study

Heinz Amenitsch1, Benedetta Marmiroli1, Fernando Cacho-Nerin1, Barbara Sartori1,Karin Jungnikl1, Ibrahimkutty Shyjumon2, Peter Laggner3, Michael Rappolt1

1Osterreichische Akademie der Wissenschaft, Schmiedlstrasse 6, 8042 Graz, Austria2Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

3Bruker AXS GmbH, Oestliche Rheinbrueckenstrasse 49, 76187 Karlsruhe, Germany

Evaporation induced self assembly (EISA) provides an attractive method for the synthesisof mesostructured materials. A fast and economically interesting process for the production ofmesostructured particles is the spray-drying process of aerosol droplets, in which the mesophaseformation proceeds within a few seconds, but still, a high degree of control on the final mesostruc-ture is possible by applying suitable process parameters. Besides the chemical composition, alsothe external conditions influencing the evaporation rate (e.g. temperature, relative humidity) havebeen identified as key parameters for the resulting structure of the mesophase. Most of the pre-vious studies have been performed on the dried aerosol and provided information on the effect ofsuch parameters on the final structure or at the end of the evaporation chamber. For the in situstudy, various setups were designed that enables the gas-phase measurements during the evapora-tion process. In an elongated evaporation vessel temperature gradients from a starting temperature(e.g. 5◦C) to final temperatures up to 400◦C can be applied within a few centimetres in the axialdirection and provoke a fast evaporation of the volatile components of the ESIA process. X-raymeasurements can be taken at steps along the temperature profile in the dryer tube and the self-assembly process can be followed with SWAXS. This presentation should give an overview of thedifferent experiments starting from the ex-situ deposition, in situ experiments of mesoporous ma-terials and finally hierarchical assembly of more complex structures.

99

Fri, 12:00

Mechanical properties of carbon nanostructures investigatedby Monte Carlo simulations

Markus Hartmann1, Melanie Todt2, David Holec1, Paul Mayrhofer1, Oskar Paris1, Franz Fischer1,Franz Rammerstorfer2

1Montanuniversitat Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria2Vienna University of Technology, Gußhausstrasse 27-29, 1040 Vienna, Austria

Carbon nanostructures are a fascinating class of materials combining high stiffness with lowweight and exceptional toughness that makes carbon a promising candidate for applications instructural mechanics. Understanding the mechanical behavior of carbon structures also on atom-istic length scales is inevitable in describing the mechanical performance and stability of large,hierarchical structures like carbon onions and fibers. In the presented work ab initio calculationswere used to extract classical potentials describing stretching, bending and torsion deformations ofcarbon bonds [1] that were used in subsequent Monte Carlo simulations to perform computationalmechanical tests on graphene, carbon nanotubes and fullerenes. These tests included the appli-cation of hydrostatic pressure, the application of a ring load and the deformation of a fullerenebetween two plates. We analyzed the elastic response, as well as the stability limits and post-buckling behavior of the structures for different sizes. The simulation results were compared to thepredictions of finite element methods to evaluate macroscopic parameters like elastic modulus orPoisson ratio of the investigated structures. In fullerenes special attention was paid to the influenceof pentagons that are inherently present in these structures. It was observed that the pentagonsdeform less than the atomic bonds in hexagonal geometry.

[1] Holec et al., Phys. Rev. B 81, 235403 (2010)

Fri, 12:15

Topologically nontrivial and nearly flat bands in multi-orbitalmodels

Maria Daghofer1, Stefanos Kourtis1, Jorn Venderbos1, Jeroen van den Brink1

1IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

For topologically nontrivial and very narrow bands, Coulomb repulsion between electrons hasbeen predicted to give rise to a spontaneous fractional quantum-Hall (FQH) state in absence ofmagnetic fields. We show that orbital degrees of freedom in frustrated lattice systems lead to anarrowing of topologically nontrivial bands for robust parameter ranges. We find that a stronglycorrelated t2g system on a triangular lattice can support a spin-chiral magnetic ordering patternwith such topologically nontrivial and flat bands. In order to go beyond mean field and to studythe impact of longer-range interactions, we map the low-energy electronic states onto an effectiveone-band model. Exact diagonalization is then used to establish signatures of a spontaneous FQHstate.

[1] J. W. F. Venderbos, M. Daghofer and J. van den Brink, Phys. Rev. Lett. 107, 116401 (2011);J. W. F. Venderbos, S. Kourtis, J. van den Brink and M. Daghofer, Phys. Rev. Lett. 108,126405(2012).

100

Fri, 12:30

Itinerant electrons in a 2-dimensional spin-ice system:Kondo-Lattice model on the checkerboard latticeJorn Venderbos1, Maria Daghofer1, Jeroen van den Brink1, Sanjeev Kumar2

1IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany2IISER Mohali, Knowledge city, Sector 81, SAS Nagar, Manauli PO 140306, India

We investigated the theory of the interplay of itinerant electrons and localized magnetic mo-ments on the frustrated checkerboard lattice as function of the super-exchange interaction betweenthe localized moments and the band filling of fermions. We find that at half filling a very robustmagnetic “flux” phase is lowest in energy. The ordering of the localized spins induces an effectivegauge field flux of π for the electrons. Consequently, this phase preserves time-reversal symmetryand the low-energy effective theory of the electrons is that of massless Dirac fermions, resemblingthe situation in graphene except that the spin degree of freedom is absent here. The robustness ofthis state originates from the geometrical frustration of the checkerboard lattice. In the crossoverregime from this flux state and the saturated FM state at vanishing super-exchange coupling, theseDirac fermions become massive with opposite sign of the mass at the two degeneracy points. Thischiral spin state is then equivalent to a time-reversal breaking anomalous Quantum Hall phase,precisely in the way once envisioned by Haldane in graphene.

101

102

9 History of Physics (GEP)HS 05.01 (Physics Building)

History of PhysicsGeschichte der PhysikPeter M. Schuster, [email protected]



13:00 - 13:20 Franz SachslehnerFranz Serafin Exner – der Anfang desII. Physikalischen Institutes

13:20 - 13:40 Wolfgang ReiterKarl Przibram (1878-1973) – Pionierder nuklearen Festkorperphysik

13:40 - 14:00 Andreas Golob

Graz physicists as agents of populareducation. The role of physics inthe Graz university-extension move-ment 1898-1938.




14:20 - 14:40 Reinhard FolkThe stony cosmos of AndreasPleninger – Astronomy and Astrologyin the 16th century

14:40 - 15:00 Bruno BesserJoseph Liesganig und die geodatischeVermessung zweier Meridianbogen inOsterreich-Ungarn

15:00 - 15:20 Armand KramlEine “physikalische Reise” durch Wes-teuropa im Jahr 1838




15:40 - 16:00 Franz PichlerElektrisiermaschinen – Ein Streifzugan Hand des Schrifttums von 1600 bis1800

16:00 - 16:20 Heinz KrennBoltzmanns Bizykel – ein mechanis-ches Analogon gekoppelter elektrischerStromkreise

103

Thu, 13:00 - 14:00, HS 05.01

Thu, 13:00

Franz Serafin Exner – der Anfang des II. PhysikalischenInstitutes

Franz Sachslehner1

1Universitat Wien, Strudlhofgasse 4, 1090 Wien, Austria

Franz Serafin Exner (1849 – 1926) folgt 1891 auf Josef Loschmidt als Vorstand des Physikalisch-Chemischen Institutes der Universitat Wien. Ihm gelingt es, mehr Raum und Personal zu erhal-ten und sein Institut allmahlich besser zu versorgen. Nach dem Tod Josef Stefans (1893) wirdversucht, Ludwig Boltzmann als Leiter des Physikalischen Instituts zu engagieren. Es tritt dieSituation ein, dass im Physikalischen Institut niemand die experimentellen Praktika abhalten will,andererseits wurde im Physikalisch-Chemischen Institut nie wirklich physikalische Chemie gemacht.Exner ubernimmt schließlich die Ausbildung in den experimentellen Praktika. So kommt es durchden Einfluss Ludwig Boltzmanns 1902 zur Neuordnung der physikalischen Institute, wobei Exn-ers Institut als II. Physikalisches Institut hervorgeht. Aufgrund des baufalligen Hauses in derTurkenstraße 3 betreiben Exner, Boltzmann und Viktor v. Lang (sowie spater Lechner) den Neubaufur die physikalischen Institute in der Boltzmanngasse 5 (eroffnet 1913). Exner wirkte auch beider Planung des Radiuminstitutes mit (1910 eroffnet) und war dessen Kurator zeit seines Lebens.Wissenschaftlich war er sehr vielseitig. Seine wichtigsten Gebiete waren: Elektrochemie, Luftelek-trizitat, Spektralanalyse und Farbenlehre. Er war auch ein Forderer der Erforschung der Radioak-tivitat. Weiters gibt es interessante erkenntnistheoretischen Arbeiten. Exner war ein beliebterund erfolgreicher Lehrer. Namen wie Hans Benndorf, Stefan Meyer, Egon v. Schweidler, EduardHaschek, Marian Smoluchowski, Erwin Schrodinger und andere zeugen davon. Die spateren No-belpreistrager Victor Franz Hess und Erwin Schrodinger waren jahrelang Mitarbeiter Exners.

Thu, 13:20

Karl Przibram (1878-1973) – Pionier der nuklearenFestkorperphysik

Wolfgang Reiter1

1Universitat Wien, Spitalgasse 2-4, 1090 Wien, Austria

Vor den Hintergrund der Rolle des liberalen judischen Wiener Burgertums des ausgehenden19. und beginnenden 20. Jahrhunderts fur die Forderung und Entwicklung von Wissenschaft undKunst werden die wissenschaftlichen Leistungen von Karl Przibram und seiner Arbeitsgruppe amInstitut fur Radiumforschung bis 1938 sowie dessen Wirken nach seiner Ruckkehr aus dem belgis-chen Exil an der Universitat Wien nach 1945 dargestellt.

104

Thu, 13:40

Graz physicists as agents of popular education. The role ofphysics in the Graz university-extension movement

1898-1938.Andreas Golob1

1Universitat Graz, Universitatsplatz 3, 8010 Graz, Austria

When the idea(l)s of the university-extension movement reached Graz from Cambridge (1871)via Vienna (1895) in 1898, aspects of physics became regular topics of the so called “VolkstumlicheVortrage”, that is popular lectures. Numerous branches of the subject, like astronomy, experimen-tal physics, geophysics and meteorology, were involved, links existed towards technical application,for example, the development of power stations, the electric grid and electric light was supported.On the other hand the dangers of this new energy source were illustrated by physicians. Rep-resentatives of the subject included less known local professors such as Leopold Pfaundler, HansBenndorf and Heinrich Ficker von Feldhaus, but also some internationally renowned scientists likeVictor F. Hess, Erwin Schrodinger and Alfred Wegener. The presentation, which is part of a workin progress on the local university-extension movement as a whole, will statistically show the con-tents of the relevant contributions and will demonstrate a handful of cases to show how knowledgewas presented and which means, like pictures, films, experiments, were used to illustrate the talks.Correspondence with local organisers in and outside Graz can also highlight attitudes towards and,respectively, reactions of the audience and help to examine the impact of the lectures which shouldnot only attract the educated bourgeoisie but also labourers and farmers, men and women alike.Early statistics will also shed some light on this question.


105

Thu, 14:20

The stony cosmos of Andreas Pleninger – Astronomy andAstrology in the 16th century

Reinhard Folk1

1Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria

In the years 1590 to 1607 six stony tables under the tile “Calendarium Perpetuum” were cre-ated by Andreas Pleninger. They demonstrate the topological order at that time. In particular onthree of this tables (on the tables in the monastery Chremsminster, in the historical museum inRegensburg and in the museum in Kassel) one finds an astrolabe, on two of them a horoscope andon one the starmaps of the northern and southern celestial sphere. The sources of this artworksand their relation to the cosmic conceptions of that time will be discussed.

[1] P. Altman Potsch, Der ewigwahrende Kalender im astronomischen Kabinett der Sternwartegenannt “Astronomischer Tisch”, Offentliches Stiftsgymnasium Kremsmunster. 154. Jahresbericht,Thalheim. 2011[2] P. Altman Potsch und R. Folk, Der astronomische Tisch des Andreas Pleninger aus dem Jahr1603, eingereicht in: “Anzeiger des Germanischen Nationalmuseums”[3] R. Folk, Das Astrolabium am Kalendertisch im Historischen Museum in Regensburg

Thu, 14:40

Joseph Liesganig und die geodatische Vermessung zweierMeridianbogen in Osterreich-Ungarn

Bruno Besser1

1IWF, Schmiedlstrasse 6, 8042 Graz, Austria

Joseph Liesganig, 1719 in Graz geboren, studierte ab 1734 Mathematik, Physik und Astronomiean der Grazer Jesuitenuniversitat. Daran anschließend studierte er Theologie an der Jesuitenuni-versitat Wien und wurde 1749 Prediger in Komarno (damals Ungarn, heute Slowakei). Nacheinem einjahrigen Aufenthalt als Mathematikprofessor am Jesuitenkolleg in Kaschau (heute Kosice,Slowakei) kehrte er 1752 als Mathematikprofessor an das Wiener Kolleg zuruck und wurde auchverantwortlich fur die dortige Jesuitensternwarte (unter der Fuhrung von Maximilian Hell). Nachder Auflosung des Jesuitenordens im Jahr 1773 verließ Liesganig Wien und wurde Direktor derstaatlichen Vermessung fur Galizien und Lodomerien in Lemberg (heute Lwiw, Ukraine), wo erauch 1799 starb. Bereits 1761/2 wurde Liesganig von Erzherzogin Maria Theresia mit der Vermes-sung eines Meridians in Osterreich-Ungarn beauftragt, woraufhin er den Meridian von Brunn (heuteBrno, Tschechien) bis Warasdin (heute Varazdin, Kroatien) auswahlte und mit Hilfe eines Trian-gulationsnetzes ausmaß. Fur diese Arbeiten wurde je eine Basislinie im Marchfeld und zwischenWiener Neustadt und Neunkirchen eingemessen. Die Arbeiten an der Meridianmessung brachtenihn auch wieder in seine steirische Heimat und 1767 waren die Arbeiten abgeschlossen. In dendarauffolgenden zwei Jahren vermaß Liesganig auch einen Meridianbogen in Ungarn, zwischenKistelek und Czurok (heute Curug, Serbien).

106

Thu, 15:00

Eine “physikalische Reise” durch Westeuropa im Jahr 1838Armand Kraml1

1Sternwarte Kremsmunster, Stift Kremsmunster, 4550 Kremsmunster, Austria

Im Sommer 1838 unternahmen drei osterreichische Physiker eine wissenschaftliche Reise durchhalb Europa. Die Reisegesellschaft setzte sich zusammen aus August Kunzek (1795-1865), damalsProfessor fur Physik in Lemberg, Andreas von Ettingshausen (1796-1878), Professor fur Physik ander Universitat Wien und P. Marian Koller (1792-1866), Direktor der Sternwarte Kremsmunster.Aus Kollers Aufzeichnungen soll diese Reise fur die Geschichte der Physik jener Zeit ausgewertetwerden. Die Reise ging uber Prag nach Berlin, Hamburg und Altona, dann per Schiff nach Lon-don. Von dort begab man sich nach Paris und Brussel. Am Schluss stand die Teilnahme an derVersammlung der Deutschen Arzte und Naturforscher, die in diesem Jahr in Freiburg im Breis-gau abgehalten wurde. Uber Munchen ging es dann wieder nach Hause. Im Vordergrund standenvor allem Besuche der Sternwarten sowie physikalischer Werkstatten und Laboratorien. Mit derDarstellung dieser Reise wird gleichsam ein Schnappschuss auf die aktuellsten Arbeitsbereiche vonastronomischer und physikalischer Forschung im Jahr 1838 gemacht. Dieser Begriff aus der Fo-tografie bietet sich besonders an, da gerade junge Technologie auf die drei Reisenden damals einebesondere Anziehungskraft ausubte.


107

Thu, 15:40

Elektrisiermaschinen - Ein Streifzug an Hand des Schrifttumsvon 1600 bis 1800

Franz Pichler1

1Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria

Der Vortrag zeigt in einer Bilderfolge anhand von im Original vorliegenden Buchern die ver-schiedenen Konstruktionen und Bauformen von Reibungselektrisiermaschinen, wie diese vom Physi-ker, Instrumentenmacher und Schausteller im Zeitraum von 1600 bis 1800 behandelt wurden. 1600markiert das Jahr, in dem der englische Arzt und Wissenschaftler William Gilbert sein Werk “DeMagnete” veroffentlichte, in dem zum erstenmal “Elektrizitat” vorkommt. Das Jahr 1800 zeigt dieEntdeckung des galvanischen Elementes durch Alessandro Volta an, eine Entdeckung, die fur diePhysik eine neue Orientierung in der Erforschung der Elektrizitat ermoglichte. Wenn auch heuteReibungselektrisiermaschinen der vorgestellten Art keine große Bedeutung mehr haben, so habenderen Entwicklung und die daran durchgefuhrten Experimente dennoch einen wichtigen Beitragzur Erforschung des physikalischen Phanomens der Elektrizitat beigetragen.

Thu, 16:00

Boltzmanns Bizykel – ein mechanisches Analogongekoppelter elektrischer Stromkreise

Heinz Krenn1

1Universitat Graz, Universitatsplatz 5, 8010 Graz, Austria

Hermann Helmholtz hatte den Begriff der “zyklischen Bewegung” fur stationare Vorgange indie klassische Mechanik eingefuhrt, womit er den Zustand einer Bewegung ohne sichtbare außereVeranderung beschrieb: Die bewegten Massenpunkte eines rotierenden Korpers werden standigdurch zyklische Bewegung ersetzt, sodass der Korper keine geometrische Veranderung – außereine Rotation - erfahrt. Dies gilt nicht nur fur stationar fließende Stromungen, sondern auchfur die fließende Elektrizitat, den elektrischen Strom. Ludwig Boltzmann hat das Helmholtz’scheMonozykel, das derartige zyklische Bewegungen beschreibt, auf das sogenannte Bizykel erweitert,einem mechanischen Apparat mit zwei gekoppelten Monozykeln. Ein ausgeklugelter Mechanismusbeschreibt die Vorgange gekoppelter Bewegungen und ist ein perfektes Analogon fur gekoppelteelektrische Stromkreise, wie z.B. einem elektrischen Transformator. In Ermangelung geeigneterelektronischer Aufzeichnungsgerate (wie z.B. einem Elektronenstrahl-Oszilloskop) stellte das Boltz-mannsche Bizykel ein hervorragendes Demonstrationsobjekt dar, um elektrische Vorgange zu veran-schaulichen. Die Konstruktion des Bizykel verdeutlicht die hohe Kompetenz von Ludwig Boltzmannals hervorragenden Experimentalphysiker, was selbst in Fachkreisen zu wenig gewurdigt wurde.

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10 Medical, Bio and Environmental Physics (MBU)SR 15.15

Medical, Bio and Environmental PhysicsMedizinische Physik, Biophysik und UmweltphysikGunther Schauberger, [email protected]

Thursday, 20th September 2012, SR 15.1514:30 - 15:30


14:30 - 14:40 Gunther Schauberger Opening of the Topical Session MBU

14:40 - 15:00 Christina HofstatterMonitoring of Radiation Exposure inthe European Columbus Laboratory ofthe International Space Station

15:00 - 15:20 Otto Scheibelhofer(Multiawesome) Multispectral Multi-probe Monitoring


Thursday, 20th September 2012, SR 15.1515:50 - 16:30


15:50 - 16:10 Stephan Winkler100-year record of 236-U/238-U incoral as a step towards establishing236-U as oceanic tracer

16:10 - 16:30 Georg PabstStalk-free membrane fusion of cationiclipids via an interdigitated phase

109

Thursday, 20th September 2012, SR 15.15

5-minute Poster Presentations†

16:30 - 17:00Time Poster-ID Presenter Title

16:30 - 16:35 POS-45† Christina Hofstatter

Review and Cross-comparison of MatroshkaPhantom Measurements inDifferent Compartmentsof the International SpaceStation

16:35 - 16:40 POS-44† Michael HajekBioequivalent Solid-StateDosimetry: Current Trendsand Future Developments

16:40 - 16:45 POS-46† Maryam Nikbakhti

Korrelation relativerFeuchte und Strom-umwandlungskoeffizient derDunnschicht-Photovoltaik

16:45 - 16:50 POS-43† Carlos Armando Alberti

Ground based MAX-DOASobservations of tropospherictrace gases in San Salvador,El Salvador

17:00 Wahl des Vorsitzenden des Fachausschusses MBU†Please find the corresponding abstracts in the poster section of this book by looking up the

Poster-ID

Thu, 14:40 - 15:30, SR 15.15

110

Thu, 14:40

Monitoring of Radiation Exposure in the EuropeanColumbus Laboratory of the International Space StationChristina Hofstatter1, Michael Hajek1, Thomas Berger2, Christine Korner2, Gunther Reitz2

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria2German Aerospace Center, Linder Hohe, 51147 Koln, Germany

Cosmic radiation and its secondaries created in interactions with spacecraft shielding structuresconstitute one of the most important hazards associated with human spaceflight. Crewmembersare facing exposures to radiation qualities that are known to produce distinct biological damagecompared with radiation on ground, and dose levels that may easily exceed those routinely receivedby terrestrial radiation workers. DOSIS is a comprehensive and overarching international dosime-try programme coordinated by the German Aerospace Centre, supporting assessment of potentialbiological implications on the health of space crew. It maps the distribution of the radiation en-vironment in the European Columbus laboratory of the International Space Station (ISS) using acomprehensive set of active and passive instrumentation to account for the cosmic-ray charge andenergy spectrum. Passive detector packages accommodating luminescence and plastic nuclear trackdetectors (PNTD) measured absorbed dose and linear energy transfer (LET) spectra at eleven sitesthroughout Columbus for mission durations of 135 days (July to November 2009) and 191 days(November 2009 to May 2010). Discussion focuses on thermoluminescence dosimetry (TLD) re-sults but strives exemplary the convolution of TLD and PNTD data to derive dose equivalent andevaluate the significance of the high-LET (≥ 10 keV/µm) contribution to the TLD dose. Theabsorbed dose distribution determined by different luminescence phosphors showed a high degreeof consistency and a distinct spatial pattern with variations of up to 22% between the sites. Thedecreased dose rate observed for the second mission is attributed to increasing solar activity andISS altitude changes.

Thu, 15:00

(Multiawesome) Multispectral Multiprobe MonitoringOtto Scheibelhofer1, Roland Hohl1, Stefan Sacher1, Jose Menezes1, Johannes Khinast1,2

1Research Center Pharmaceutical Engineering GmbH, Inffeldgasse 21a, 8010 Graz, Austria2Graz University of Technology, Inffeldgasse 21a, 8010 Graz, Austria

In the food and pharmaceutical industry, near-infrared spectroscopy is a more and more fre-quently used tool for process monitoring. This is motivated by its fast and non-invasive nature.Further on, no extensive sample preparation is needed, enabling the use as an online process an-alytical tool. However, this comes with the drawback of large amounts of correlated data, ofteninfluenced by many external factors. Therefore, a lot of effort has to be invested in the correct useof mathematical tools to extract the information of interest. Here we put to use a new prototypeNIR spectrometer (by EVK, Raaba, Austria), based on an established chemical imaging system, toenable the reading of several attached probes at the same time. However, even when investigatingthe same sample, there are slight differences from one probe to another. On the one hand, thisis caused by their different field of view; on the other hand, these are to be avoided disturbances,on nominally similar probes. Therefore, it is necessary to identify these disturbances and considerthem in the spectral interpretation. This should allow the monitoring of processes at different posi-tions, as well as the simultaneous monitoring of different processes, with one measurement system.In this work, data from the prototype system are presented in use on a pharmaceutical process.It is shown how to overcome some of the appearing difficulties when dealing with a multiprobesystem, in order to enable fast and robust process monitoring, and render process control.

111


Thu, 15:50 - 16:30, SR 15.15

Thu, 15:50

100-year record of 236-U/238-U in coral as a step towardsestablishing 236-U as oceanic tracer

Stephan Winkler1, Peter Steier1, Jessica Carilli2

1University of Vienna, Wahringer Straße 17, 1090 Vienna, Austria2Australian Nuclear Science and Technology Organization, Lucas Heights, New South Wales 2234, Australia

Since uranium is known to behave conservatively in ocean waters, 236-U has great potential inapplication as oceanic tracer. 236-U (t1/2=23.4Ma) was introduced into the oceans by atmosphericnuclear weapon testing with amounts estimates ranging from 700kg to 1500kg. Thus a resultinginitial average 236-U/238-U ratio of at least 5e-9 is expected for an oceanic mixed layer depthof 100m. This ratio is significantly higher than the natural pre-nuclear age background, which isexpected to be at 1e-14 levels. However, even the elevated ratios of global stratospheric fall-out arebeyond the capabilities of ICPMS and TIMS methods. However, the exceptional sensitivity andultra-low background for 236-U of the Vienna Environmental Research Accelerators AcceleratorMass Spectrometry system allows us to measure down to 1e-13 detection limits. We present ayear-by-year record of 236-U/238-U for a Caribbean coral core covering years 1944 to 2006, thusallowing to us put constraints on the oceanic input of 236-U by atmospheric testing. Moreovermodelling of the results also demonstrates the capabilities of 236-U as oceanic tracer.

112

Thu, 16:10

Stalk-free membrane fusion of cationic lipids via aninterdigitated phase

Georg Pabst1, Caroline Lonez2, Michel Vandenbranden2, Jacques Jestin3, Aurel Radulescu4,

Jean-Marie Ruysschaert2, Thomas Gutberlet5

1Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria2Faculte des Sciences, Universite Libre de Bruxelles, CP 206/2, Campus Plaine, Blvd. du Triomphe, 1050 Brussels, Belgium

3Laboratoire Leon Brillouin, CEA/CNRS, C.E.A Saclay, 91191 Gif-sur- Yvette Cedex, France4Julich Centre for Neutron Science, Lichtenbergstrasse 1, 85747 Garching, Germany5Helmholtz-Zentrum Berlin GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

Packaging of DNA is a central concept in gene therapy in order to overcome membranebarriers. One possibility is to use cationic lipids, which may form various aggregate structureswhen complexed with DNA, due to an intricate interplay of electrostatic interactions (see e.g.[1]).One highly promising lipid candidate is N-t-butyl-N’-tetradecyl-3-tetradecylaminopropionamidine(diC14-amidine), which shows high fusion capabilities with target membranes. Interestingly and incontrast to other lipids, fusion of diC14-amidine vesicles is significantly enhanced in the gel phase.Therefore, we have performed a comprehensive X-ray and neutron small-angle scattering as well asdilatometry and ultrasound velocimetry study on diC14-amidine. We found an anomalously thinlamellar fluid phase at high temperatures, which transforms into a loosely packed interdigitatedphase below the chain melting transition. Typical fusion pathways via point-like defects (stalks)can therefore be ruled out in order to explain amidine’s unusual fusion behavior. Instead, we pro-pose that the loose lipid packing leads to a significant exposure of the hydrophobic lipid core tothe aqueous phase, reducing energy penalties from the removal of water during fusion.

[1] A.V. Radhakrishnan, S. K. Ghosh, G. Pabst, V. A. Raghunathan, and A. K. Sood, Proc. Natl.Acad. Sci. 109: 6394 - 6398 (2012).[2] G. Pabst, C. Lonez, M. Vandenbranden, J. Jestin, A. Radulescu, J.-M. Ruysschaert, and T.Gutberlet, Soft Matter, (2012), DOI: 10.1039/c2sm25665g.

113

114

11 Surfaces, Interfaces and Thin Films (OGD)HS 15.02

Surfaces, Interfaces and Thin FilmsOberflachen, Grenzflachen und dunne SchichtenChristian Teichert, [email protected]



09:00 - 09:20 Erminald BertelSurface Phases on 122 Fe Based Super-conductors: An Indication of ChargeDensity Wave Fluctuations?

09:20 - 09:40 Bernhard StogerScanning Tunneling Microscopy studyof single-crystalline Sr3Ru2O7

09:40 - 10:20 Robert SchennachPaper - A Material with Unique Prop-erties

10:20 - 10:40 Matus MilkoUnderstanding the electronic structureof weakly bound nanohybrid systems

10:40 - 11:00 David EggerReliably Modeling the Properties ofa Complex Inorganic-Organic HybridSystem




14:30 - 14:50 Marcus RennhoferGrowth of ZnO nano-rods solar-cellmaterial on ITO investigated by X-Ray-diffraction

14:50 - 15:10 Franz SchmiedTip-enhanced Raman Spectroscopy –challenges and opportunities

15:10 - 15:30 Herbert ReingruberNew advanced microscopic methodsfor detailed analysis of strong asym-metric microfiltration membranes


115



15:50 - 16:20 Gregor HlawacekUHV Helium Ion Microscopy – a newtool for surface science?

16:20 - 16:40 Alexander VolkDeposition of Metal Clusters FormedInside Superfluid Helium Nanodroplets

16:40 - 17:00 Martin DenkA novel two-dimensional Cu-tungstate(CuWOx) phase on Cu(110)

17:00 - 17:20 Mandy Grobosch

Organic PCBM field effect transistors:Analysis of the contact properties bycombined photoemission spectroscopyand electrical measurements

17:20 - 17:40 Roland ReselSurface Induced Crystal Structures:Crystal Growth and Structure Solu-tion

17:40 - 18:00 Daniel LuftnerThe electronic structure of pentacenemonolayers on Ag(110) and Cu(110)



09:00 - 09:20 Joongil Jake ChoiZrO2 ultra-thin films on Pd3Zr(0001):Structure and growth of metal clusters

09:20 - 09:40 Markus KratzerAFM based electrical investigations onGe nanodomes on Si(001)

09:40 - 10:20 Tomas SikolaIn situ observation of the growth ofgermanium nanofibres

10:20 - 10:40 Zbynek NovotnyOrdered Array of Single Au Adatomson Fe3O4(001) with Remarkable Ther-mal Stability

10:40 - 11:00 Josef RedingerStrain and structure driven complexmagnetic ordering of a CoO overlayeron Ir(100)


116



11:30 - 12:10 Peter ZeppenfeldMicroscopy and Spectroscopy of ultra-thin organic layers and nanocrystals

12:10 - 12:30 Eva Reinisch

Cs doping of organic semiconductingmonolayers: probing the electronicand geometric structure with angle re-solved UPS

12:30 - 12:50 Levent TumbekThe influence of venting on the is-land size distribution observed forHexaphenyl on mica

12:50 - 13:10 Margareta WagnerGrowth and structure of Tetraphenyl-porphyrin on Cu(110)-p(2x1)O

13:10 - 13:40 Stefan MulleggerSTM Studies of Surface-SupportedStable Hydrocarbon Radicals

117

Thu, 09:00 - 11:00, HS 15.02

Thu, 09:00

Surface Phases on 122 Fe Based Superconductors: AnIndication of Charge Density Wave Fluctuations?

Erminald Bertel1, Michael Cordin1, Peter Amann2, Alexander Menzel1, Mikhail Baranov1,Sebastian Diehl1, Josef Redinger3, Cesare Franchini4

1University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria2Vorarlberg University of Applied Sciences, Hochschulstrasse 1, 6850 Dornbirn, Austria

3Vienna University of Technology, Gußhausstrasse 25-25a, 1040 Vienna, Austria4University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria

On the cleavage planes of 122 Fe based superconductors two different long-range ordered struc-tures can be found, i.e. a (2× 1) phase prevalent after cleavage at low temperature and a

√2×√

2phase found after cleavage at room temperature. The majority of groups attributes these structuresto an adlayer of earth alkali metal atoms. The existence of different long-range ordered structurescorresponding to the same coverage in different temperature regimes is extremely rare in surfacesystems and requires an active role of the substrate in the ordering process. The adsorbate systemBr/Pt(110) exhibits analogous phases, namely a (2 × 1)4-Br/Pt(110) structure at T < 50 K anda c(2× 2)-Br/Pt(110) structure at room temperature. The phase transition is associated with theremoval of a periodic lattice distortion (PLD) and an accompanying charge density wave (CDW)in the substrate as T is increased. At sufficiently low temperature the fluctuating CDW/PLDorder parameter is stabilised by the adsorbate in a lock-in type mechanism. A similar mechanismcan account for the observations on the 122 Fe pnictide surfaces suggesting the presence of CDWfluctuations at low temperature.

Thu, 09:20

Scanning Tunneling Microscopy study of single-crystallineSr3Ru2O7

Bernhard Stoger1, Zhiming Wang1, Marcel Hieckel1,2, Florian Mittendorfer1, Raimund Podloucky2,

Josef Redinger1, David Fobes3, Zhiqiang Mao3, Michael Schmid1, Ulrike Diebold1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria2University of Vienna, Sensengasse 8/7, 1090 Vienna, Austria

3Tulane University, 2001 Percival Stern Hall, 6400 Freret St, New Orleans, LA, USA

Perovskite oxides play an important role as cathodes in solid oxide fuel cells (SOFC) and incatalysis. Investigating surface defects such as oxygen vacancies and the adsorption of relevantmolecules helps gaining more insight into the physics behind SOFCs and catalytic processes. High-quality Sr3Ru2O7 (SRO) single crystals were grown using the floating zone technique. The SROsamples were cleaved at 150 K under UHV conditions and subsequently investigated by STM at 78K and 6 K. To determine which species are imaged in STM, doped SRO samples were investigatedand STM simulations were performed. Furthermore, we have characterized the defects that arepresent at the as-cleaved surfaces, and how reactive they are if exposed to CO and O2. STM showsthat CO binds to some defects at the surface and, possibly, also to apical oxygen atoms at theperfect surface. The interaction between the clean surface and CO was also investigated by DFTcalculations. This work was supported by the Austrian Science Fund (FWF project F45).

118

Thu, 09:40, Keynote

Paper - A Material with Unique PropertiesRobert Schennach1

1Graz University of Technology, Petersgasse 16/2, 8010 Graz, Austria

Paper is one of the oldest man made materials, which one is using on a daily basis for thingslike writing, printing, wrapping or carrying goods. However, one hardly stops to think about thisquite unique material. Paper has several unique properties due to its very hierarchical structurefrom the cellulose molecules via the paper fibers up to the paper network. The current view of thesurface structure and surface chemistry of paper fibers will be presented, which play an importantrole in the formation of the bonds between the individual fibers in the paper network. The natureof the fiber - fiber bond in paper is still under discussion, but researchers agree that mechanicalinterlocking, inter diffusion, hydrogen bonds, Van der Waals bonds and Coulomb interactions doplay a role. However, it is not yet clear to which extend these bonding forces play a role in pa-per strength. In addition, the influence of capillary bridges will be discussed. While it is agreedthat they play an important role during bond formation (as paper is simply made by spraying asuspension of paper fibers in water on a sieve and then drying the sheet of paper), it is an openquestion whether or not capillary bridges still play a role in dry paper. Recent experimental resultsconcerning this questions will be discussed.

Thu, 10:20

Understanding the electronic structure of weakly boundnanohybrid systems

Matus Milko1, Claudia Draxl2, Peter Puschnig1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Humboldt-Universitat zu Berlin, Newtonstraße 15, 12489 Berlin, Germany

We present an ab initio study on the formation of electronic states at the interface in weaklybound hybrid nanostructures. As an example, we study the polymer poly-para-phenylene embed-ded in a zig-zag nanotube, for which we vary the diameter up to the limiting case of graphene.It turns out, that besides the anticipated electronic level alignment with respect to the vacuumpotential, three additional factors impact the electronic structure of the combined system. First,we observe a difference in the electrostatic potential outside and inside the nanotube, which isassociated with its curvature. Second, an interface dipole arises from the charge redistributionwithin the sub-units. Finally, mutual polarization effects of the polymer and its host are shownto play an important role in the level alignment. We investigate in detail, how these three factorsdepend on size and spatial arrangement of the constituents, and the fact whether the nanotube ismetallic or semiconducting. Based on this knowledge, we propose a simple scheme to predict thenanohybrid’s electronic structure from the bands of its constituents alone.

119

Thu, 10:40

Reliably Modeling the Properties of a ComplexInorganic-Organic Hybrid System

David Egger1, Victor Ruiz2, Wissam Al-Saidi3, Tomas Bucko4, Alexandre Tkatchenko2,

Egbert Zojer1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany

3University of Pittsburgh, Pennsylvania 15261, USA4Comenius University, mlymska dolina, 84215 Bratislaba, Slovakia

When different materials align to form hetero-structures, the final electronic properties are of-ten determined by the connecting interface. In nowadays organic-electronic devices, where severalsemiconductor/metal and semiconductor/semiconductor interfaces are an integral part of commondevice geometries, controlling these interfaces is not only necessary to maintain device functional-ity, but might even be exploited towards designing electronic features from the bottom-up. In thispresentation, we seek for a microscopic insight into these interfaces and the relevant physical andchemical processes. A prototypical metal-supported organic double-layer system – copper phtalo-cyanine (CuPc) on 3,4,9,10-perylene tetracarboxylic dian-hydride (PTCDA) adsorbed on Ag(111) –is investigated by means of semilocal density-functional theory (DFT) based band-structure compu-tations. Including van der Waals (vdW) interactions through PBE+vdWsurf, a recently developedscheme where dispersion-corrected DFT is combined with the Lifshitz-Zaremba-Kohn theory toaccount for the polarizability within the metallic surface [Phys. Rev. Lett. 108, 146103 (2012)],we underline the importance of dispersive interactions and physisorptive bonding at the interfacesin CuPc@PTCDA@Ag(111). Comparing our results to recent experimental data [Phys. Rev. Lett.108, 106103 (2012)], we find very good agreement for adsorption distances and CuPc-induced shiftsin the electronic structure of the PTCDA/Ag(111) interface. These findings are rationalized byvdW-interactions, thus highlighting their consideration as being imperative for a microscopic un-derstanding and quantitatively accurate modeling of interfaces in complex metal-organic systems.


120

Thu, 14:30 - 15:30, HS 15.02

Thu, 14:30

Growth of ZnO nano-rods solar-cell material on ITOinvestigated by X-Ray-diffraction

Marcus Rennhofer1, Herwig Peterlik1, Johanna Akbarzadeh1, Erhard Schafler1,Stephan Abermann2, Antun Peic2, Theodorus Dimopoulos2, Hubert Brueckl2

1University of Vienna, Strudlhofgase 4, 1090 Vienna, Austria2Austrian Institute of Technoloy, Donau-City-Strasse 1, 1220 Vienna, Austria

ZnO is a wide bandgap (∼3.2 eV) semiconductor, crystallizing in the hexagonal wurtzite form.It is natively n-type doped and possesses favorable properties such as high transparency, highelectron mobility and strong room temperature-luminescence. In the last years great interest wasattracted towards ZnO nanostructures such as nanorods (NR). ZnO NR arrays have been investi-gated for various applications in a number of emerging areas one of them solar cells. This workfocuses on the controlled electrochemical growth of ZnO NRs on Sn-doped In2O3 (ITO)-coatedglass substrates. The structural development of NRs on the initial stages of growth was analyzedby different XRD techniques. The formation of the crystalline ZnO-structure could be measuredusing WAXS-geometry. The WAXS measurements show that ZnO-structure peaks of the ZnO-NRon the ITO substrate occur for deposition times longer than 1 min. Peaks of the directions (100),(002), (101), (102) and (110) could be identified. The formation of the (002) peak – being the fa-vorable direction for producing well aligned ZnO-NR – is the strongest pronounced. The formationof the single peaks is linear in time. There was no shielding of the ITO peaks visible. The FWHMof all peaks was nearly stable for all deposition steps as was the position of the peaks. The resultsimply that the use of preparation techniques known from chemical industry and industrial scaleallow to manufacture cheap and efficient solar cells.

Thu, 14:50

Tip-enhanced Raman Spectroscopy – challenges andopportunities

Franz Schmied1,2, Tatiana Perova1, Silvia Giordani1, Paula Colavita1, Robert Schennach2,3

1University of Dublin, Trinity College Dublin, College Green, Dublin 2, Ireland2CD-Laboratory for Surface Chemical and Physical Fundamentals of Paper Strength, Graz University of Technology, Petersgasse 16/2, 8010

Graz, Austria3Institute of Solid State Physics, Graz University of Technology, Petersgasse 16/2, 8010 Graz, Austria

Tip-enhanced Raman Spectroscopy (TERS) is a new technique that combines the scanningcapabilities of atomic force microscopy (AFM) with Raman spectroscopy on the nanometer scale.Here, a metal-coated AFM tip acts as nanoantenna, which enhances the weak Raman signal ofthe Near Field by orders of magnitude and allows for overcoming the optical diffraction limit. Acrucial role in reaching optical resolution down to 10nm plays the nanoantenna. Here, we presenttechniques (vapor-coated, electroless chemical deposition) to metal-coated commercially availableAFM probes suitable for TERS measurements on opaque samples in upright configuration. Fur-ther, we address interpretation of signal “blinking” in TERS spectra that belongs to carbonaceouscontamination and live-time issues of the used coating. The financial support of Mondi, ScienceFoundation Ireland, and the Austrian Federal Ministry of Economy, Family and Youth and theNational Foundation for Research, Technology and Development is gratefully acknowledged.

121

Thu, 15:10

New advanced microscopic methods for detailed analysis ofstrong asymmetric microfiltration membranes

Herbert Reingruber1, Armin Zankel1, Peter Polt1

1Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria

Filtration is a very essential technology in various fields of science. Concerning the watershortage of many countries the importance of filtration technology gets clear. For many of theseapplications microfiltration membranes are used. Modern filtration membranes are high tech prod-ucts delivering high flux rates compared with well defined retention properties, due to their specialasymmetric pore structure. For membrane optimization new techniques of characterizing them areessential. This work shows the development and results of two new characterization methods basedon electron microscopic methods. One method allows a three dimensional (3D) reconstruction ofthe membrane structure. This was accomplished by automated serial sectioning and subsequentimaging of the membrane cross-section. The achieved image stack was used for 3D reconstructions.From the reconstruction, parameters like the inner membrane surface, the local porosity or bymeans of fluid simulations the water was flux calculated. The obtained data are in agreement withexperimental data. However the properties of the pore walls (whether they are hydrophilic or hy-drophobic) cannot be measured with this method. Therefore the microscopic membrane structurewas studied additionally under wet conditions. For this aim the microscope sample chamber canbe used as micro- laboratory in order to establish “environmental” conditions. By cooling of themembrane water can condensate and the interaction of the pores with water can be observed. Thenumber and size distribution of wet and dry pores during such a wet- drying experiment can beobtained.


122

Thu, 15:50 - 18:00, HS 15.02

Thu, 15:50, Invited

UHV Helium Ion Microscopy – a new tool for surfacescience?

Gregor Hlawacek1, Vasilisa Veligura1, Raoul van Gastel1, Harold Zandvliet1, Bene Poelsema1

1University of Twente, Carre CR 2.213, P.O. Box 217, 7500 AE Enschede, Netherlands

Helium Ion Microscopy (HIM) is a new tool that allows high resolution imaging of a widerange of materials. The fact that the technique is not limited to conductive materials and themany different contrast mechanisms make it a promising tool for nano structure research. HIMhas demonstrated unprecedented resolution both on conductive and isolating materials. It is well-known for its high surface sensitivity when using secondary electrons generated by the impingingions. Chemical sensitivity is possible via the backscattered He. Both qualitative element contrastmaps as well as quantitative localized Rutherford Backscattering are possible. In addition Ionolu-minescence allows to obtain information on the bandstructure and defects, such as color centers,by analyzing the emitted photons. The extension of the method to UHV conditions and the highsurface sensitivity allow to investigate surface and interface properties with a high spatial reso-lution. Investigated systems of interest to surface science include self assembled monolayers andthin films of conjugated molecules. However, I will also show results on the visualization of buriedinterfaces and demonstrate how crystallographic information can be obtained. In all cases the rel-evant contrast mechanisms will be discussed. This research is supported by the Dutch TechnologyFoundation STW, which is the applied science division of NWO, and the Technology Programmeof the Ministry of Economic Affairs.

Thu, 16:20

Deposition of Metal Clusters Formed Inside SuperfluidHelium Nanodroplets

Alexander Volk1, Markus Koch1, Evelin Fisslthaler2, Werner Grogger2, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Graz University of Technology, Steyrergasse 17/III, 8010 Graz, Austria

We have recently successfully synthesized silver (Agn) and chromium (Crn) nanoclusters in-side superfluid helium nanodroplets (Hen) and deposited these metal clusters on an amorphouscarbon (a-C) surface. Transmission electron microscope (TEM) images shall be presented as wellas microbalance measurements. During the past decade, Hen turned out to offer a unique exper-imental environment, combining both a least perturbing superfluid quantum matrix at 0.4 K anda well defined local confinement, given by the droplet radius of a few nanometres. Therefore thesenanocryostats are well suited for the synthesis of metal nanoclusters. The first surface depositionof nanoclusters (Agn) assembled inside Hen has only recently been demonstrated [1]. We werenow able to deposit Crn using the same method. The comparison of Agn and Crn measurementsindicates a strong oxidation of Crn, while this is not the case for Agn. In the next step we wantto form bimetallic core shell structures in Hen by sequential particle pickup. Due to the forma-tion process in the favourable superfluid environment, we expect a radial symmetric structure ofthese bimetallic nanostructures, where a shell of silver atoms encloses and therefore passivates thechromium core. Besides the TEM images and microbalance investigations, we seek to present moredetailed chemical information obtained from X-ray photoelectron spectroscopy (XPS), energy dis-persive X-ray spectroscopy (EDX) and electron energy loss spectrometry (EELS) measurements.

[1] E. Loginov, L. F. Gomez, and A. F. Vilesov; J. Phys. Chem. A 115, 7199-7204 (2011)

123

Thu, 16:40

A novel two-dimensional Cu-tungstate (CuWOx) phase onCu(110)

Martin Denk1, David Kuhness1, Margareta Wagner1, Svetlozar Surnev1, Fabio Negreiros2,Luca Sementa2, Giovanni Barcaro2, Alessandro Fortunelli2, Falko Netzer1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, I-56124, Pisa, Italy

We explore the feasibility to fabricate W-oxide nanostructures on metal surfaces via self-assembly and condensation of (WO3)3 clusters, deposited directly from the gas phase: here wereport the formation of a novel two-dimensional Cu-tungstate CuWOx phase on Cu(110). A beamof (WO3)3 cluster molecules, formed by sublimation of WO3 powder at ∼900-1000◦C in a ther-mal evaporator, has been directed onto a Cu(110)2×1-O surface oxide at low temperature andthe surface has been annealed subsequently at 600 K. At low temperature (<15 K) the (WO3)3clusters adsorb in intact molecular form, albeit in a somewhat distorted cluster geometry. Uponheating to 600K, the (WO3)3 molecules dissociate and react with the Cu-O(2×1) surface oxide,forming a wetting monolayer with a well ordered incommensurate structure. The latter has beenstructurally characterized by high-resolution STM imaging and LEED. The chemical nature andelectronic structure of this novel 2-D W-O-Cu layer has been investigated by high-resolution XPScore level spectroscopy, NEXAFS, and valence band spectra. The unusually sharp W 4f core levelspectra, the specific NEXAFS fingerprint and the evolution of the valence band all suggest thatthis 2-D W surface oxide is of a Cu-tungstate CuWOx type. Density functional calculations arein progress to help elucidating the physical and chemical nature of this unusual surface oxide phase.

Thu, 17:00

Organic PCBM field effect transistors: Analysis of thecontact properties by combined photoemission spectroscopy

and electrical measurementsMandy Grobosch1, Ingo Horselmann2, Susanne Scheinert2, Martin Knupfer3, Gernot Paasch3

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Technische Universitat Ilmenau, Ehrenbergstrasse 29, 98693 Ilmenau, Germany

3IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany

Source/drain contacts in OFETs based on a solution prepared modified PCBM were charac-terized by combined X-ray and ultra violet photoemission spectroscopy (XPS, UPS) and electricalmeasurements of the OFET. Thereby the sample preparation for the different measuring principleshas been realized in parallel, differing only in the layer thickness of the polymer. By means of UPSa reduced work function could be demonstrated for differently prepared, sputtered, and as-receivedAu and Al contacts in agreement with previous publications [1]. On top of the Al contacts a nat-ural AlOx layer could be identified. For both the PCBM/Au and PCBM/Al systems UPS a holeinjection barrier of 1.8 eV has been determined by UPS in agreement to previous published data.Considering the energy gap of 2.0 eV [2] for PCBM the electron injection barrier would be the sameof 0.2 eV. In addition, the metal/organic interface Au/PCBM/Al has been investigated by meansof combined XPS and UPS. The deposition of Au on the PCBM films results in a growth of goldclusters and a non-closed Au film. In contrast to the identical hole injection barriers for Au andAl bottom contacts as following from UPS, the OFET currents differ by more than two orders ofmagnitude. A possible origin of this striking discrepancy will be presented.

[1] M. Grobosch et al., Adv. Mater. 19 (2007) 754.[2] Z.-L. Guan et al., Organic Electronics 11 (2010) 1779.

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Thu, 17:20

Surface Induced Crystal Structures: Crystal Growth andStructure Solution

Roland Resel1, Armin Moser1, Ingo Salzmann2, Raphaele Della Valle3, Michele Sferrazza4,Yves Geerts4

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Humboldt-Universitat zu Berlin, Newtonstrasse 15, 12489 Berlin, Germany

3Universita di Bologna, Via Zamboni, 33 - 40126 Bologna, Italy4Universite Libre de Bruxelles, Campus de la Plaine, 1050 Bruxelles, Belgium

A large number of organic semiconductors exhibits polymorphism and well-known phenomenaare specific crystallographic phases which are present exclusively in thin films. Such crystallo-graphic phases are often denoted as surface induced phases, since the presence of a surface duringthe crystallisation is of primary importance for their formation. In general, such thin-film poly-morphs do not exist as macroscopic free standing single crystals. A number of surface inducedcrystal structures of conjugated molecules have been solved during the last years, examples arein particular application relevant molecules like pentacene. Within the talk the crystallisationbehaviour of different calamitic conjugated molecules will be described: pentacene, sexithiopheneand dihexyl-terthiophene. It is found that surface induced phases are formed by various techniquesof thin film preparation. Solution based methods as well as physical vapour deposition can yieldsurface induced phases. Important parameters for preparation are the type of surface, the evapo-ration rate (or deposition rate) of the solvent during the thin film preparation and the temperatureof the substrate during the crystallisation process. Similarities and differences in the molecularpacking between known crystal structures and surface induced phases will be discussed. Of partic-ular importance for the formation of surface induced crystal structures is the formation of the firstmolecular monolayer on a surface. Based on the experimental observations, thermodynamic issueswill be finally discussed, especially if surface induced crystal structures are metastable phases orthermodynamically stable phases due to the presence of a surface.

Thu, 17:40

The electronic structure of pentacene monolayers on Ag(110)and Cu(110)

Daniel Luftner1, Thomas Ules1, Michael Ramsey1, Georg Koller1, Peter Puschnig1


We present a combined theoretical and experimental study of ordered monolayers of pentacene(5A) on Ag(110) and Cu(110). Theoretically, we have performed ab-initio calculations within theframework of density functional theory for the adsorbed monolayers and analyzed their electronicstructure in terms of projected density of states and photoemission cross sections within the plane-wave final-state approximation. In addition, we have undertaken GW-calculations for isolatedpentacene, bulk pentacene and a freestanding layer of pentacene to emphasizing that G0W0 cor-rections greatly improve DFT band gaps. Thereby, we also demonstrate that the G0W0 gaps arestrongly dependent on the local environment of the pentacene molecule, an effect which is absentin DFT. Experimentally, the valence electronic structure of pentacene monolayers are studied byangle-resolved photoemission spectroscopy. Thereby, an extensive data set of the photocurrent I asa function of parallel momenta (kx,ky) and binding energy Eb has been obtained. This data cubeis compared with simulated momentum maps of various pentacene molecular orbitals of an isolatedmolecule. Thereby, we can unambiguously identify four molecular states between the Fermi leveland the top of the Ag d-band. By including the substrate in momentum map calculations, we areable to detect possible modifications of molecular states due to the interaction with the substrate.On comparing monolayer on Ag(110) and Cu(110), we find that 5A is oriented parallel to thesubstrate [1-10]-direction on Cu(110) and perpendicular to it on Ag(110).

125

Fri, 09:00 - 11:00, HS 15.02

Fri, 09:00

ZrO2 ultra-thin films on Pd3Zr(0001): Structure and growthof metal clusters

Joongil Jake Choi1, Ulrike Diebold1, Michael Schmid1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria

Despite its importance in many areas of industry such as catalysis, fuel cell technology andmicroelectronics, the surface structure and physical properties of ZrO2 are yet not well under-stood. We report a STM, AES and XPS study of ultra-thin ZrO2 films prepared by oxidation of aPd3Zr(0001) crystal. A clean Pd3Zr(0001) surface with wide terraces (100 – 200 nm) was obtainedby the Ar sputtering and annealing at 900 ◦C. A homogeneous ZrO2 film was grown by 30 minutesof oxidation of Pd3Zr(0001) at 450 ◦C in an oxygen pressure of 5 × 10−9 Torr and annealing at900 ◦C for 10 minutes in UHV. The film has a fluorite trilayer (O-Zr-O) structure with an in-planelattice constant of 0.350 ± 0.001 nm and a (

√43 ×

√43)R7.6◦ superstructure cell with respect

to the substrate (asubst.= 0.5612 nm). Electron bombardment results in oxygen vacancies with adesorption cross-section of ∼ 170 pm2. When depositing small amounts of Au, we find single Auad-atoms and clusters of various sizes (1 – 1.5 nm). The single Au atoms disappear at 470 K andlarger clusters diffuse through the oxide to substrate at > 600 K. Pd clusters behave similar to Au,but diffuse through the oxide at a lower temperature ( > 500 K).

Fri, 09:20

AFM based electrical investigations on Ge nanodomes onSi(001)

Markus Kratzer1, Christian Prehal1, Maria Rubezhanska2, Yury Kozyrev2, Sergey Kondratenko3,Christian Teichert1

1Montanuniversitat Leoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria2 O. O. Chuiko Institute of Surface Chemistry , 17 Generala Naumova St., 03164, Kyiv, Ukraine

3Taras Shevchenko National University of Kyiv, Physics Dept. pr. Acad. Glushkova 2, Kyiv, Ukraine

The potential application of nanodots, nanowires, and nanodomes (NDs) in optoelectronicsand photovoltaics has triggered intensive research on such low-dimensional nanostructures. In thiswork, we report on the electrical characterization of individual Ge nanodomes utilizing conductiveatomic force microscopy (C-AFM), and photoconductive AFM (PC-AFM. The Ge ND samples wereprepared by means of molecular beam epitaxy (MBE) on Si(001) substrates under ultra-high vac-uum (UHV) conditions. Facetted islands exhibiting {113} and {15 3 23} facets could be identifiedvia AFM topography measurements. The AFM based electrical characterizations were performedunder ambient conditions in dark and under illumination. Two-dimensional current maps revealeda higher conductivity of the NDs compared to the surrounding. Conductivity variations withinsingle NDs could be observed, which will be discussed with respect to Ge ND facets an siliconintermixing. Local current-to-voltage (IV) measurements on top of individual NDs revealed a de-pendence of the IV characteristics on the ND size. Additionally, the generation of a photovoltagedue to light exposure has been observed. Support in the framework of the Ukrainian-Austrianprojects M/139-2007 and UA-11/2009 is acknowledged.

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Fri, 09:40, Keynote

In situ observation of the growth of germanium nanofibresTomas Sikola1, Miroslav Kolıbal2

1Brno University of Technology, Technicka 10, 61669 Brno, Czech Republic2Brno University of Technology, Technicka 2, 61669 Brno, Czech Republic

Although several routes for fabrication of NWs exist, the vapor-liquid-solid (VLS) process isthe most versatile approach in the production of group IV and III-V semiconductor NWs. In thismethod the metallic droplet has to be fed with the growth material, which is supplied in the form ofgas molecules (CVD) or an atomic beam (PVD). The CVD method is used more frequently in fab-rication of NWs than the PVD one, however, the latter method is more useful for in situ monitoringof the growth as its operation pressure is lower and, hence, more characterization techniques canbe applied. In the contribution, in situ monitoring of 〈110〉 oriented Ge nanowire growth by SEMwill be discussed. It will be shown that germanium nanowires can be grown by a vapor-liquid-solidprocess in 〈110〉 directions both on Ge(100) and Ge(111) substrates if very low supersaturation inthe collector droplet is ensured. This is also supported by in-situ observations of nanowire kinkingtowards 〈111〉 direction occurring more frequently at higher evaporation rates. Further, it will bedemonstrated that the hexagonal cross-section of germanium nanowires grown in the 〈110〉 direc-tion by physical vapor deposition is a consequence of minimization of surface energy of the collectordroplet. If the droplet is lost or solidified, two {001} sidewall facets are quickly overgrown and thenanowire exhibits a rhomboidal cross-section. This process can be controlled by switching betweenthe liquid and solid state of the droplet, enabling the growth of nanowires with segments havingdifferent cross-sections. These experiments will be supported by a theoretical model. In the endbasic principles of the fabrication of regular arrays of nanowires by the guided growth of metallicdroplets on substrates pre-patterned by focused ion beam will be discussed.

Fri, 10:20

Ordered Array of Single Au Adatoms on Fe3O4(001) withRemarkable Thermal Stability

Zbynek Novotny1, Giacomo Argentero1, Zhiming Wang1, Michael Schmid1, Ulrike Diebold1,

Gareth Parkinson1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria

We present a scanning tunneling microscopy investigation of gold deposited at the magnetiteFe3O4(001) surface at room temperature. This surface forms a reconstruction with c(2×2) sym-metry [1], where pairs of Fe and neighboring O ions are slightly displaced laterally, forming un-dulating rows with ‘narrow’ and ‘wide’ adsorption sites. At fractional monolayer coverages, singleAu adatoms adsorb exclusively at the ‘narrow’ sites, with no significant sintering up to annealingtemperatures of 400◦ C[2]. The strong preference for ‘narrow’ site is possibly related to charge andorbital ordering within the first subsurface octahedral layers of the reconstructed Fe3O4(001) sur-face[3]. Because of their high thermal stability, the ordered Au atoms at Fe3O4(001) reconstructedsurface should provide useful insights into the chemical reactivity of single atomic species. Thismaterial is based upon work supported as part of the Center for Atomic-Level Catalyst Design,an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science,Office of Basic Energy Sciences under Award Number #DE-SC0001058.

[1] Pentcheva, R. et al. Phys. Rev. Lett 2005, 94, 126101.[2] Novotny, Z. et al., Phys. Rev. Lett. 108, 216103 (2012)[3] Lodziana, Z. Phys. Rev. Lett. 2007, 99, 206402.

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Fri, 10:40

Strain and structure driven complex magnetic ordering of aCoO overlayer on Ir(100)

Josef Redinger1, Florian Mittendorfer1, Michael Weinert2, Raimund Podloucky3

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria2University of Wisconsin–Milwaukee, P.O. Box 413, 2200 E. Kenwood Blvd., Milwaukee, WI 53201-0413, USA

3University of Vienna, Sensengasse 8/7, 1090 Vienna, Austria

The magnetic ordering in the ultrathin c(10×2) CoO(111) film supported on Ir(100) has beeninvestigated on the basis of ab-initio calculations. A close relationship between the local structuralproperties of the oxide film and the induced magnetic order was found, which leads to alternatingferromagnetically and anti-ferromagnetically ordered CoO segments. While the local magnetic or-der is directly related to the geometric position of the Co atoms, the mismatch between the CoOfilm and the Ir substrate leads to a complex long-range order of the oxide.


128

Fri, 11:30 - 13:40, HS 15.02

Fri, 11:30, Keynote

Microscopy and Spectroscopy of ultrathin organic layers andnanocrystals

Peter Zeppenfeld1, Lidong Sun1, Thorsten Wagner1, Johannes Gall1, Daniel Queteschiner1,

Michael Hohage1

1Johannes-Kepler-Universitat, Altenbergerstrasse 69, 4040 Linz, Austria

We report on the investigation of organic layers, thin films and nanocrystals using optical spec-troscopy (RDS and SDR), Photo Emission Electron Microscopy (PEEM) and Fluorescence / LaserScanning Confocal Microscopy (FM/LSCM). The combination of these methods enables us to mon-itor the growth in situ (RDS/SDR, PEEM) and to explore the correlation between the structureand morphology of the organic films with the electronic and optical properties at a microscopicscale (PEEM, FM/LSCM). Exploiting the polarization dependence of the light in RDS, PEEM andFM allows to determine the orientation of the molecules and to identify structural phase transi-tions. STM and LEED provide supplementary information on the arrangement of the molecules onthe surfaces, whereas operating the PEEM with a He UV-lamp allows recording local UPS spectrafrom the grown films and from individual nanocrystals. Examples will be shown for sexithiophene(6T) and porphyrins on different single crystalline metal surfaces or mica.

Fri, 12:10

Cs doping of organic semiconducting monolayers: probing theelectronic and geometric structure with angle resolved UPS

Eva Reinisch1, Thomas Ules1, Georg Koller1, Peter Puschnig1, Markus Ostler2,Stephen Berkebile1, Thomas Seyller2, Michael Ramsey1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2University Erlangen Nurnberg, Erwin-Rommel-Strasse 1, 91058 Erlangen, Germany

Cesium-deposition on ordered organic semiconducting thin films induces changes in the elec-tronic structure and geometric orientation of the molecules. The current investigation is focusedon rodlike Sexiphenyl (6P) and Pentacene (5A) molecules adsorbed on Ag(110) and Cu(110) sub-strates. In an undoped 6P monolayer on Cu(110), we observe flat lying molecules with the LUMObeing filled by hybridisation with the surface. Upon Cs deposition first the molecules are tiltedand decoupled from the surface, thus the LUMO is emptied. Further Cs deposition subsequentlyleads to electron charge transfer from the alkali metal to the molecular orbitals, filling first theLUMO, then LUMO+1, with increasing amounts of Cs. In contrast, in an undoped 6P monolayeron Ag(110) the LUMO is empty. Upon Cs deposition the 6P molecules on Ag(110) are dopedsimilar to 6P on Cu(110). Significantly, prior to charge transfer doping, the initial Cs exposureazimuthally reorients the molecules of the 6P and 5A monolayer on Ag(110) from perpendicular toparallel to the substrate corrugation. This contrasts to Cu(110) where both molecules lie parallelto the Cu-rows before and after Cs deposition. This suggests a strong influence of the Cs atoms onthe molecule-substrate bonding. The results will be discussed in the light of comparison betweenthe experimental band (E, k) and momentum map (kx, ky) of ARUPS with DFT calculations.This work is supported by the Austrian Science Fund (FWF), projects P21330-N20 and P23190-N16.

129

Fri, 12:30

The influence of venting on the island size distributionobserved for Hexaphenyl on mica

Levent Tumbek1, Christoph Gleichweit1, Karin Zojer1, Adolf Winkler1


A frequently observed feature in the growth of para-hexaphenyl on freshly cleaved mica is theappearance of a bimodal island size distribution. In this case long needle-like islands, composedof lying molecules, are embedded in a sea of small clusters. Recently, it has been shown that themodification of the mica surface by Ar+ ion sputtering, or by the pre-adsorption of carbon orpotassium, leads to a different growth behavior. Now the islands are of dendritic shape, composedof standing molecules. Surprisingly, again a bimodal growth mode can be observed. We havere-examined both growth scenarios in detail, using in-situ thermal desorption spectroscopy (TDS)and ex-situ atomic force microscopy (AFM). We found strong evidence that in both cases the smallcrystallites are caused by a dewetting process, which takes place when the in-vacuo grown films areexposed to air for the ex-situ AFM investigations. This was discovered when TD spectra were takenbefore and after venting the vacuum chamber. The very different origin of the two sets of islandsis also constituted in a very different density, morphology and size distribution of the islands. Thephenomenon of subsequent venting induced nucleation could be successfully described by KineticMonte Carlo (KMC) simulations. The result of these simulations was that about seven moleculesconstitute the critical island size.

Fri, 12:50

Growth and structure of Tetraphenylporphyrin onCu(110)-p(2×1)O

Margareta Wagner1, Sina Gusenleitner1, Tatjana Djuric2, Stephen Berkebile1, Roland Resel2,

Michael Ramsey1, Falko Netzer1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Tetraphenylporphyrin (H2TPP) has been grown on Cu-O and previously investigated elec-tronically and structurally by LEED, UPS, NEXAFS and XRD (ex-situ). Surprisingly the samesurface structure has been found for both the monolayer and thick film, exhibiting the rather diluteH2TPP(5 10 3) plane. Whereas the narrow spacing and stacking of the layers in the bulk phase stilllead to a dense thick film, the monolayer has been assumed to consist of a single H2TPP(5 10 3)layer only. However, this would be rather unusual, as porphyrines have been reported to form densepacked monolayers on various surfaces. In this LT-STM work the true structure of the H2TPPmonolayer has been revealed. It could be demonstrated, that two H2TPP(5 10 3) planes mergeinto a commensurate single dense layer, which is stable due to the strong interaction with the Cu-Osurface, and provides an excellent template for crystalline film growth. This work has been sup-ported by the by the Austrian Science Foundation (FWF) within the National Research Network“Interface Controlled and Functionalized Organic Films” and the ERC Advanced Grant “SEPON”.

130

Fri, 13:10, Invited

STM Studies of Surface-Supported Stable HydrocarbonRadicals

Stefan Mullegger1, Mohammad Rashidi1, Michael Fattinger1, Reinhold Koch1

1Johannes-Kepler-Universitat, Altenbergerstrasse 69, 4040 Linz, Austria

Stable free radicals can be stored and investigated under ambient conditions, which makesthem desirable for applications as polarizing agents or novel magnetic materials as well as suitablemodel systems for investigating sp2 magnetism in reduced dimensions. We have studied the stableall-organic spin-1/2 radical, α,γ-bisdiphenylene-β-phenylallyl (BDPA), adsorbed on a weakly inter-acting metal support by low-temperature scanning tunneling microscopy (LT- STM). We report onthe structure, self-assembly, frontier orbital electronic and magnetic properties, and radical-radicalinteractions at the atomic-scale.

131

132

12 Careers in Physics (PIE)HS 15.03

PIE, Phsics-Industry-EnergyPIE, Physik-Industrie-EnergieDoris A. Steinmuller-Neth, [email protected]



13:00 - 13:15 Doris Steinmuller-NethlIndustrial Research and gender aspects– future for physicists in Europe?

13:15 - 13:30 Jochen KraftHerausforderungen in der Chipent-wicklung fur die industrielle Fertigung

13:30 - 13:45 Martin ZimmerlingBeschaftigungsmoglichkeiten furPhysiker in der Medizintechnik-Industrie

13:45 - 14:00 Gerhard MurerCareers for Physicists’ in the Analyti-cal Instruments Industry

14:00 - 14:15 Josef Siess Wie man Berufung zum Beruf macht

133

Thu, 13:00 - 14:30, HS 15.03

Thu, 13:00

Industrial Research and gender aspects – future for physicistsin Europe?

Doris Steinmuller-Nethl1

1KOMET RHOBEST GmbH, Exlgasse 20a, 6020 Innsbruck, Austria

Industry has a leading role in research, innovation and development. European companies needexperts and scientists to boost their innovation and competitiveness. Physicists can fulfill theserequirements. Industrial research opens the possibility to develop innovative technologies and prod-ucts for the benefit of humankind. Interdisciplinarity and diversity are key factors for success. Inthis presentation the female physicist Doris Steinmuller-Nethl, will report about the challenges ofher profession, hurdles she was confronted with and her passion for technology. This short glimpseinto promising career options in industrial research should give an impetus for young physicists totrust and develop their talents and realize their opportunities.

Thu, 13:15

Herausforderungen in der Chipentwicklung fur dieindustrielle Fertigung

Jochen Kraft1

1AUSTRIAMICROSYSTEMS AG, Schloss Premstatten, 8141 Unterpremstatten, Austria

Jochen Kraft absolvierte ein Diplom-Physik Studium an der Ruprecht-Karls Universitat inHeidelberg und promovierte an der Karl-Franzens Universitat Graz im Gebiet Oberflachen- undHalbleiterphysik. Im Anschluss war er in der Chip Fertigung bei MICRONAS AG (Freiburg)als Defekt-Ingenieur beschaftigt. Seit 13 Jahren arbeitet er in der Forschungs- und Entwick-lungsabteilung von ams AG (fruher: austriamicrosystems). ams ist ein fuhrender Anbieter vonAnalog-Losungen im Bereich Power Management, Sensor und Sensor-Schnittstellen und Wireless.Das Schaltungsdesign, die Fertigung und der Chip Test ist bei ams unter einem Dach vereint. Dr.Kraft zeigt einige “High-Lights” aus seiner Entwickler-Tatigkeit bei ams. Insbesondere die neuerenAktivitaten im Bereich 3D Integration und Si-Durchkontakte werden vorgestellt. Die 3D Tech-nologie ermoglicht das Stapeln von Chips, z.B. die Herstellung eines Chips mit einem Sensor aufder einen Seite und der CMOS-Auswerteschaltung auf der anderen Seite. Der Signaltransfer durchden Chip findet mit Durchkontakten statt. Auf diese Weise werden Verdrahtungen vermieden, diezeitverzogernd wirken und relativ viel Platz benotigen.

134

Thu, 13:30

Beschaftigungsmoglichkeiten fur Physiker in derMedizintechnik-Industrie

Martin Zimmerling1

1Med-El Elektromedizinische Gerate GmbH, Furstenweg 77a, 6020 Innsbruck, Austria

Forschung und Entwicklung werden in der Medizintechnik auch in Zukunft großgeschriebenwerden, um neue Entwicklungen im Gesundheitssystem zu unterstutzen und dieses und weiterhinfinanzierbar zu halten. Daraus ergeben sich viele Betatigungsfelder auch fur Physiker. Nebenvielfaltigen Herausforderungen im Forschungs- und Entwicklungsbereich finden sich auch im Pro-duktmanagement, in der Qualitatssicherung, im Zulassungsbereich sowie im Patentwesen span-nende und interessante Aufgabenbereiche. Martin Zimmerling leitet als Physiker die Implanta-tentwicklung des weltweit tatigen osterreichischen Cochleaimplantat-Herstellers MED-EL. Er wirduber seine Berufserfahrungen in der Medizintechnik berichten. Junge Physiker erfahren in dieserPrasentation auch, welche Fahigkeiten und Zusatzqualifikationen einen Einstieg und erfolgreichesberufliches Weiterkommen in der Medizintechnik erleichtern.

Thu, 13:45

Careers for Physicists in the Analytical Instruments IndustryGerhard Murer1

1Anton Paar GmbH, Ankerstrasse 6, 8054 Graz, Austria

The Analytical Instruments Industry is expected to have a sales volume of 45 Billion US$ in2012 and employs some 300.000 people worldwide. The industry and the company the presenterworks for are briefly introduced. Of the 300.000 employed in the industry a considerable num-ber is physicists. The presentation highlights career opportunities for physicists in the industry,in particular in the areas of research and technology development, product development, productmanagement as well as sales.

Thu, 14:00

Wie man Berufung zum Beruf machtJosef Siess1

1Europaisches Service fur Personalvermittlung und Unternehmensgrundung, Paulanergasse 15/2, 1040 Wien, Austria

Ausgebildete Physiker und Physikerinnen nehmen verstarkt wichtige Managementaufgaben ingroßen Unternehmen, Konzernen und in der Politik wie auch als Forscher in ihren ureigenstenDisziplinen wahr. Welche weiteren hard und soft skills von Unternehmungen und Organisationengefragt und gefordert werden, wenn Spitzenpositionen besetzt werden, werden in diesem Vortragangesprochen und an Beispielen gezeigt. Was junge Physiker und Physikerinnen fur ihre eigeneKarriereplanung beachten sollen, welche Zusatzqualifikationen oder Nischen (Spezial-) Kenntnisseaußerhalb der wissenschaftlichen Uni-Laufbahn weiterhin nachgefragt sein werden, werden in diesemkurzen Vortrag beleuchtet und sollen Mut machen, auch abseits der Physiklaufbahn Bewerbungengezielt zu platzieren. Wie man Berufung zum Beruf macht.

135

136

13 Posters

Wednesday, 19th September 201217:45 - 20:00

AMPPoster-ID Presenter Title

POS-01 Naveed Anjum

Experimental Investigations of the Hy-perfine Structure of 143Nd+ Spectrallines using Collinear Laser Ion BeamSpectroscopy

POS-02 Birgit BrandstatterAn ion-photon interface mediated by acavity

POS-03 Michaela EllmeierOmni-directional magnetic field mea-surement by means of the CoupledDark State Magnetometer (CDSM)

POS-04 Simon Eschlbock-FuchsInfluence of sample temperature on thedynamics and emission line intensitiesof laser-induced plasma

POS-05 Marcelo Goulart Electron driven chemistry close to 0 K

POS-06 Sebastian KramerEfficient wave function simulations innonlinear quantum optics using anadaptive coherent state basis

POS-07 Michael NiedermayrIn situ ion-trap fabrication apparatusfor low ion-heating rates

POS-08 Matthias SchreitlTowards a nuclear clock with Thorium-229

137


FAKT

Poster-ID Presenter Title

POS-09 Stefan BrunnerNew Approaches for Improvement ofTime-of-Flight PET

POS-10 Gunther CronenbergqBounce: Ein Frequenzstandard furGravitationsspektroskopie

POS-11 Jacqueline Erhart Momentum Analysis in PERC

POS-12 Philip HaidenDesign of the Magnetic Shielding forPERC

POS-13 Katharina IseppStrangeness Production in p-p Colli-sions at FOPI

POS-14 Michael Klopf Proton Spectroscopy with PERC

POS-15 Wolfgang LuchaLocal-Duality QCD Sum Rules forPseudoscalar-Meson Form Factors

POS-16 Martin MartschiniInvestigations of negative ion forma-tion in Middleton type ion sources

POS-17 Martin MoserElektronen-Energie-Detektion furPERC

POS-18 Thomas PotocarA new very-large Perfect Crystal Neu-tron Interferometer

POS-19 Babak RahbaranGlobal Trigger Upgrade project for theCMS experiment at LHC

POS-20 Stephan Winkler

Recent Advances in Accelerator MassSpectrometry of the actinides at theVienna Environmental Research Ac-celerator

138


FKP & NESYPoster-ID Presenter Title

POS-21 Johanna AkbarzadehThe Impact of Temperature and Elec-tric Fields on Surfactant-Molecules -an in-situ SAXS Study

POS-22 Tanja EtzelstorferX-ray strain microscopy on Ge micro-bridges

POS-23 Petra GranitzerMagnetic study of iron oxide nanopar-ticles dispersed within porous silicon

POS-24 Nina HraudaHigh Resolution X-Ray DiffractionStudies on Arrays of SiGe Islands

POS-25 Stefan KirnstotterProton implanted silicon wafers inves-tigated by electron beam induced cur-rent measurements

POS-26 Martin LeitnerTowards kinetic Monte-Carlo simula-tions with ab initio accuracy

POS-27 Roland Johann Morak

Wood templated inorganic nanoporousmaterials: Formation and water ad-sorption studied by in situ SAXS ex-periments

POS-28 Maurizio MussoPolarisation-dependent Raman char-acterization of stibnite (Sb2S3)

POS-29 Josef OswaldNumerical simulations of scanning gateexperiments in the quantum Hall effectregime

POS-30 Silvia PabischThe nanomechanics of feather keratinstudied by small-angle X-ray scatter-ing

139


FKP & NESY (continued)Poster-ID Presenter Title

POS-31 Manuel PachecoFabrication and optical characteriza-tion of CdSe quantum dots

POS-32 Peter ParzDefects in an iron-nickel meteorite ex-amined with positrons

POS-33 Harald RennhoferNegative thermal expansion of carboncrystallites measured in single carbonfibres

POS-34 Mathias SassermannToward polarisation entangled photonpairs from microcavity exciton polari-tons

POS-35 Alexander SchmonElektromagnetische Levitation –Beruhrungsfreie Untersuchung vonflussigem Metall an der TU Graz

POS-36 Paolo SereniPolarization-dependent Raman char-acterization of Stibnite (Sb2S3) in thetemperature-range 290K-77K

POS-37 Manuel VieiderModeling disorder in self-assembledmonolayers with embedded dipoles


GEPPoster-ID Presenter Title

POS-38 Martin LeitnerAlfred Wegener: Second Expedition toGreenland - A photographic window tothe past

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Wednesday, 19th September 201217:45 - 20:00LHS (PUS)


POS-39 Hans Eck Kinder reisen durch die Wissenschaft

POS-40 Erich ReichelForschendes Lernen als Methode derKompetenzforderung

POS-41 Engelbert Stuetz Mit Magnetfeldern horen

POS-42 Stefanie Anna Tritthart Papier erleben


MBU

POS-43† Carlos Armando AlbertiGround based MAX-DOAS observa-tions of tropospheric trace gases in SanSalvador, El Salvador

POS-44† Michael HajekBioequivalent Solid-State Dosimetry:Current Trends and Future Develop-ments

POS-45† Christina Hofstatter

Review and Cross-comparison of Ma-troshka Phantom Measurements inDifferent Compartments of the Inter-national Space Station

POS-46† Maryam NikbakhtiKorrelation relativer Feuchte undStromumwandlungskoeffizient derDunnschicht-Photovoltaik

† 5-minute poster-presentation on Thursday, 20th September 2012, 16:30 - 17:00

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OGDPoster-ID Presenter Title

POS-47 Christian GanserAFM investigation of kraft pulp fiberswelling in controlled humidity

POS-48 Christoph GleichweitKinetic Monte Carlo Simulations ofNucleation and Thin Film Growth ofHexaphenyl on Amorphous Mica

POS-49 Michael HohageSusceptibility measurements of Ninanostructures on Cu(110)

POS-50 Markus KratzerDynamic plowing lithography and 6Pthin film growth on graphene investi-gated by atomic force microscopy

POS-51 Patrice KreimlMorphological investigations of viscosefibers by atomic force microscopy

POS-52 David KuhnessGrowth and structure of WOxnanolayers on bare Cu(110) andCu(110)(2×1)O surfaces

POS-53 Albrecht MiletzkyAdsorption of Xylan onto BleachedSoftwood Fibers

POS-54 Monika MirkowskaThe contact charging of insulators byatomic force microscopy

POS-55 Thomas ObermuellerAnisotropic growth of ultrathin Mn-oxide nanostructures on Ag(100)

POS-56 Jirı PavelecSurface Chemistry Chamber for anal-ysis of Oxides

POS-57 Andreas PavitschitzMicroscopical electrical investigationsof grain boundaries in ZnO varistor ce-ramics

142


OGD (continued)Poster-ID Presenter Title

POS-58 Alexander PichlerStructure Solution of Surface InducedCrystal Structures: Selected Examplesof Calamitic Conjugated Molecules

POS-59 Bernhard PutscheInfluence of potassium on the nucle-ation and growth of para-hexaphenylon mica

POS-60 Sebastian RohmThin cellulose films as model systemsfor paper-fibres

POS-61 Boris ScherwitzlInitial growth of Rubicene on SiliconOxide

POS-62 Anton TamtoglBismuth surface phonon modes fromhelium atom scattering experiments

POS-63 Levent Tumbek

Attachment limited versus diffu-sion limited nucleation of organicmolecules: Hexaphenyl on sputter-modified mica

POS-64 Thomas UlesDisplacement and Replacement in Or-ganic Heterostructures

POS-65 Zhiming WangReversible transitions between surfacereconstructions on SrTiO3

POS-66 Frederik WeberInvestigation of the surface charge ofViscose Fibres by XPS and ATR

POS-67 Archim Wolfberger

Selective Photo-induced Cross-linkingof Polynorbornens: Towards the Fab-rication of Polymer 2D- and 3D- Mi-crostructures


PMP


POS-68 Maurizio Musso Raman investigation of tannin foams

POS-69 Soran NabaviThe effect of sacrificial bonds on themechanical behavior of a single poly-mer chain- A Monte Carlo study

143

Wed, 17:45 - 20:00

POS-01, AMP, Wed, 17:45

Experimental Investigations of the Hyperfine Structure of143Nd+ Spectral lines using Collinear Laser Ion Beam

SpectroscopyNaveed Anjum1,2, Nadeem Akhtar1,2, Harry Huhnermann1,3, Laurentius Windholz1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Optics Labs. P. O. Box 1021, Nilore Islamabad, Pakistan3Department of Physics, University of Marburg, Germany

We have used the high resolution technique of collinear laser ion beam spectroscopy (CLIBS)for Doppler free investigations of the hyperfine structure (hfs) of spectral lines of singly ionizedNeodymium-143 (143Nd+). Hyperfine structure is caused by the electromagnetic interaction be-tween the nucleus and the electron shell. The study of the hyperfine structure of ions can provideuseful information on the nuclear structure and electronic properties of the ions. We used naturalNd in metallic form to produce Nd ions using a surface ion source of Johnson type. Natural Nd isa mixture of five stable and two radioisotopes and the natural abundance of 143Nd is just 12.2%.The ions are accelerated to 20 kV and then mass separated by an 80◦ magnet. A collimated ionbeam is obtained in the interaction region. In the interaction region the ion velocity is tunedby applying an additional voltage and keeping the laser frequency constant (Doppler tuning). Aring dye laser, pumped by an Argon ion laser, is used as the excitation source and we used dyesRhodamine 6G and Sulforhodamine B (Kiton Red) to obtain the desired laser wavelengths. Laserinduced fluorescence is recorded by using a photomultiplier tube and a photon counter. Magneticdipole constants A and electric quadrupole constants B of the involved levels have been determinedusing a fit program. The accuracy of our results is better than that of published values.

POS-02, AMP, Wed, 17:45

An ion-photon interface mediated by a cavityBirgit Brandstatter1


Quantum networks, in which atoms at quantum nodes are linked by photonic channels, offera compelling solution to the challenge of scalability in quantum computing. In these networks,optical cavities provide an interface between photons and atoms. We use a trapped calcium ion,which allows for efficient initialization, coherent manipulation, and readout of the quantum state.The ion is coherently coupled to the polarization state of single photon via a high-finesse cavity bydriving a vacuum-stimulated Raman transition. We show state mapping of an arbitrary electronicsuperposition state of the ion to a polarization superposition state of a single photon. In a newexperimental setup, we plan to increase the coherent coupling between ion and photon to reach thestrong-coupling regime by decreasing the cavity mode volume using fiber Fabry-Perot cavities.

144

POS-03, AMP, Wed, 17:45

Omni-directional magnetic field measurement by means ofthe Coupled Dark State Magnetometer (CDSM)Michaela Ellmeier1, Roland Lammegger1, Andreas Pollinger2, Werner Magnes2,

Laurentius Windholz1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Osterreichische Akademie der Wissenschaften, Schmiedlstrasse 6, 8042 Graz, Austria

The CDSM magnetometer is a new type of optical pumped magnetometer, which measuresthe scalar value of the magnetic field. The measurement principle is based on the coupling of twodark state resonances established by the coherent population trapping (CPT) effect. The darkstate resonances are excited by a circularly polarized, polychromatic laser field consisting of twofrequency components 6.8 GHz apart from each other. As a consequence, six magnetic field depen-dent dark states are created within the hyperfine structure of the 87Rb D1 line, which are combinedby a multi-stage modulation process to three coupled dark state resonances. The magnitude of themagnetic field is obtained by extracting the appropriate modulation frequency lying in the rangeof 300 Hz-1 MHz by means of phase sensitive detection techniques. The benefit of this approachis a significant reduction of the (buffer gas induced) temperature shift of the dark resonances. Incontrast to other scalar magnetometers, the CDSM can measure magnetic fields independent ontheir direction (without the so called dead zones). This novelty is achieved by a proper selectionof the resonance with maximum amplitude during the permanent operation of the magnetometer.Therefore, exact knowledge about the relative strengths of the dark resonances is necessary. Wedemonstrate that the optical pumping effect causes an asymmetry between the coupled resonances,resulting in a totally different angular dependence of the dark resonance amplitudes compared topredictions of theoretical models. This behaviour is used with benefits in the CDSM operationdynamics.

POS-04, AMP, Wed, 17:45

Influence of sample temperature on the dynamics andemission line intensities of laser-induced plasma

Simon Eschlbock-Fuchs1, Michael Haslinger1, Andreas Hinterreiter1, Philipp Kolmhofer1,Norbert Huber1, Roman Rossler2, Johannes Heitz1, Johannes Pedarnig1

1Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria2Voest Alpine Stahl, Voest-Alpine-Strasse 3, 4031 Linz, Austria

We investigate the influence of sample temperature on the dynamics of the laser induced plasmaand on the emission intensities in laser-induced breakdown spectroscopy (LIBS). Bulk aluminum,boron doped silicon, and metallurgical slag samples are heated in air up to temperature TS ≤500 ◦C and are irradiated by Nd:YAG laser pulses (wavelength 1064 nm, pulse duration approx.7ns). The plasma dynamics is investigated by fast time-resolved photography. LIBS spectra aretaken with an Echelle spectrometer in combination with an intensified CCD camera. For all sam-ple materials investigated the temporal evolution of the plume size and of the LIBS intensitiesvaries systematically with TS. The height and width of the plasma plume and the luminosity ofthe plasma, as measured by fast photography, increase with increasing temperature. For Al and Sithe plasma lifetime is extended to ∼ 10 µs at TS = 500 ◦C (compared to ∼ 4 µs at TS = 20 ◦C).For slag samples the plasma lifetime does not significantly vary with TS. Increasing emission lineintensities are observed for all samples at high temperature. We apply the calibration-free LIBSmethod to analyze the measured emission spectra and to determine the concentration values forthe major oxides in slag at different sample temperature. The LIBS analysis of multi-componentsamples at high temperature is of interest for technical applications. Acknowledgements: We thankthe Austrian Federal Ministry of Economy, Family and Youth and the National Foundation for Re-search, Technology and Development for financial support.

145

POS-05, AMP, Wed, 17:45

Electron driven chemistry close to 0 KMarcelo Goulart1, Peter Bartl1, Samuel Zottl1, Mathias Daxner1, David Gschliesser1,Johannes Postler1, Carolina Guedes Matias1, Benjamin Puschnigg1, Violaine Vizcaino1,

Christian Leidlmair1, Harald Schobel1, Lukas An der Lan1, Stephan Denifl1, Andreas Mauracher1,Michael Probst1, Olof Echt2, Andrew Ellis3, Paul Scheier1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria2University of New Hampshire, DeMeritt Hall 323, 9 Library Way, Durham, New Hampshire, 03824, USA

3University of Leicester, University Rd, Leicester, LE1 7RH, UK

Homogeneous as well as heterogeneous clusters are formed upon pickup of individual atomsand molecules by He nanodroplets. Evaporative cooling of the He matrix leads to an isothermaltemperature of 0.37 K. Fragmentation of the dopant cluster during the pickup process is completelyquenched by the surrounding He matrix, leading to a neutral cluster size distribution free of anymagic numbers. Positive and negative ion formation is studied via electron bombardment of thedoped He nanodroplets utilizing mass spectrometry. Intensity anomalies of the cluster size distribu-tions indicate fragmentation processes of the dopant clusters after the ionization process and reflectthe stability of the differently sized charged clusters. Electron ionization of He nanodroplets dopedwith methanol (M) forms predominantly the protonated cations MnH+. Several other abundantcluster ion series can be assigned as (H2O)xMnH+ with x = 1 – 5. The intracluster reaction leadingto the formation of H2O requires a minimum number of methanol molecules, which is n = 5+4x.This work is financially supported by the FWF (P19073, P23657, and L633)

POS-06, AMP, Wed, 17:45

Efficient wave function simulations in nonlinear quantumoptics using an adaptive coherent state basis

Sebastian Kramer1, Helmut Ritsch1


We show that a suitable set of coherent basis states placed on a discrete hexagonal grid canbe used to numerically very accurately represent general quantum states in a memory efficientway. Adding an algorithm for dynamic basis adaptation allows highly accurate Quantum MonteCarlo wave function simulations with small basis sets. At the example of the intricate nonlineardynamics of an optical parametric oscillator around threshold, we demonstrate that this approachyields accurate time dependent solutions with a substantially smaller basis sets than required fora photon number basis. Above threshold the adaptive basis splits into localized subsets allowingefficient representation of bimodal or even more complex phase space distributions and directlyyields an intuitive physical picture of the ongoing dynamics.

146

POS-07, AMP, Wed, 17:45

In situ ion-trap fabrication apparatus for low ion-heatingrates

Michael Niedermayr1


One promising approach for scalable quantum-information-processing architectures is based onminiaturised surface ion traps. At present, one significant limit to miniaturisation is set by theheating rate of ions, which increases as the ions approach the trap surface. The mechanism ofthis heating is not yet fully understood, but experimental results indicate that one likely cause iscontamination on the surface of the trap electrodes. This is present even after only the briefest ex-posure to atmosphere. This effect might be mitigated by performing the final trap-fabrication stepsin situ, in vacuum. We describe a system to investigate the heating rates of contamination-freegold surface traps. The cryogenic ion-trap chamber is equipped with a thermal evaporation sourcein vacuum which allows in situ coating of the trap surface with a fresh gold layer. The heating ratewill be measured before and after the evaporation.

POS-08, AMP, Wed, 17:45

Towards a nuclear clock with Thorium-229Matthias Schreitl1, Thorsten Schumm1, Georgy Kazakov1, Georg Winkler1, Georg Steinhauser1


An improvement of the current time standard could be achieved by exploiting optical transi-tions with long lifetimes and narrow line widths. Nuclear transitions, which can be more stableagainst external perturbations, usually have energies in the range of keV or even MeV. Thorium-229however is predicted to provide a unique excited state only 7.6±0.5 eV [1] above the ground state inthe range of UV lasers. An expected lifetime of several hours [1] makes this transition an excellentcandidate for a new time standard, with a potential to outperform existing clocks by orders of mag-nitudes. Our experimental approach consists in embedding Th4+ in the UV-transparent crystalstructure of CaF2. This provides the advantages of working with a room-temperature solid-statesample with a great number of nuclei. The next steps include the characterization of the crystalsdoped with Th-232 in order to ensure the transparency in the relevant wavelength region, the re-liable substitution of the Thorium ions in the crystal lattice and the role of defects. A broadbandUV-lamp will subsequently be used to try to excite the predicted nuclear transition and detectfluorescence in a crystal doped with Th-229. A frequency comb is currently set up which will betransferred to the 160 nm region by a high-harmonic generation build-up cavity and will be usedas a precision measurement tool for comparison to other frequency standards.

[1] Beck et al., Phys. Rev. Lett. 98, 142501 (2007)

147

POS-09, FAKT, Wed, 17:45

New Approaches for Improvement of Time-of-Flight PETStefan Brunner1, Lukas Gruber1, Albert Hirtl2, Johann Marton1, Martin Jankovec2, Peter Knoll3,

Ken Suzuki1

1Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria2Medical University of Vienna, Wahringer Gurtel 18-20, Leitstelle 3L , 1090 Wien, Austria

3Wilhelminenspital, Montleartsrasse 37, 1160 Wien, Austria

Advances in detector technology led to the construction of commercial time of flight (TOF)positron emission tomography (PET) devices, resulting in enhanced image contrast, lower patient’sdose and shorter examination times. Commercial TOF-PET scanners with coincidence time res-olutions of 500-600 ps FWHM are already available. Goal of this work is the improvement oftime resolution for TOF-PET using Silicon photomultipliers (SiPM) and the Cherenkov effect.Along with many comparable features to ordinary vacuum photomultipliers, SiPMs are consider-ably smaller in size and insensitive to magnetic fields, which makes them usable for hybrid devicessuch as PET-NMR. The use of the Cherenkov effect at gamma energies of 511keV should help toimprove time resolution of PET detectors dramatically. As Cherenkov photons are emitted almostinstantaneously, compared to scintillation photons, the ability to detect and distinguish them fromthe scintillation signals, provide precise time stamps for TOF. First measurements using PMTshave been accomplished successfully. For the development of a future TOF-PET prototype, MonteCarlo (MC) simulations using the framework GATE and SLitrani are performed to optimise theexperimental setup (pixel size, material, arrangement of the SiPMs). The simulated raw data havebeen analysed by self-developed software and first sinograms have been calculated. In this work theresults of recent measurements on the time resolution of our setup, calculations and measurementsrelated to the detection of Cherenkov photons at energies of 511keV, and latest results of MCsimulations on new detector designs, will be presented.


qBounce: Ein Frequenzstandard furGravitationsspektroskopie

Gunther Cronenberg1, Hanno Filter1, Tobias Jenke1, Hartmut Abele1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria

Wir wenden eine Spektroskopiemethode quantisierter Zustande ultrakalter Neutronen im Gravi-tationspotential an. Diese Methode erlaubt prazise Messungen der quantenmechanischen Ubergangsfrequenzeneines Schrodinger-Wellenpakets, welches im Schwerefeld der Erde auf einem Neutronenspiegel os-zilliert. Den Ubergangsfrequenzen entsprechen dabei Energiedifferenzen der Eigenzustande im Pi-coelektronenvoltbereich, welche nur von der Neutronenmasse, der lokalen Erdbeschleunigung, sowievom Planckschen Wirkungsquant abhangen. Messungen mit ultrakalten Neutronen erlauben auf-grund ihrer nicht vorhandenen Ladung sowie extrem geringer Polarisierbarkeit eine Sensitivitatauf das Newtonsche Gravitationsgesetz oder Abweichungen durch hypothetische, kurzreichweit-ige Wechselwirkungen ohne den Einfluss elektromagnetischer Storeffekte. Damit konnen Grenzenauf theoretisch interessante Modelle wie Große Extradimensionen der Raumzeit oder Axionen indem vergleichsweise wenig untersuchten Mikrometerbereich abgeleitet werden. Eine weitere Aus-baustufe dieser Methode bringt als Vorteil die Selbstfokussierung des Aufbaus, welche eine großereGeschwindigkeitsklasse und damit eine hohere Zahlrate der untersuchten Neutronen erlaubt.

148


Momentum Analysis in PERCJacqueline Erhart1, Gertrud Konrad1, Xiangzun Wang1, Hartmut Abele1


The new user facility “Proton and Electron Radiation Channel” (PERC) supplies an intensebeam of charged decay products arising from the beta decay of free neutrons. This weak interactionprocess tests the Standard Model and searches for possible extensions. Different detector systemsare under development in order to study angular correlations involving the neutron spin, the ener-gies and the momenta of the β-decay products (electrons and protons). Already existing beta decayspectrometers were focused on the measurement of electron and proton energy while PERC per-mits precise momentum spectroscopy of charged particles for the first time. At the exit of PERC,the electrons and protons leaves the magnet system with a field strength of 0.5T. Therefore, themagnetic field has to drop down rapidly and guarantee the non-adiabatic motion of the particles atthe passage to the momentum spectrometer. The new detection concept has to provide a weak ver-tical magnetic field to separate the particles due to their momenta and charges. The electrons andprotons are detected by position sensitive detectors. In this way, electrons and protons can be mea-sured at the same time. The new concept of analyzing the momentum spectra provides an increasedresolution in the low energy scale which is needed for investigating, e.g., the Fierz interference term.


Design of the Magnetic Shielding for PERCPhilip Haiden1, Jacqueline Erhart1, Harald Fillunger1, Miklos Horvath1, Gertrud Konrad1,

Stefan Schwarz1, Xiangzun Wang1, Hartmut Abele1


The new facility PERC (Proton Electron Radiation Channel) is a novel source of neutron de-cay products. PERC is currently under development by an international collaboration and will beinstalled at the FRM II in Garching, Germany. The main component of PERC is a more than 11m long superconducting magnet system, with a strong longitudinal magnetic field of 0.5 T up to 6T. In order not to disturb other experiments in the vicinity of PERC, we have designed a magneticfield return yoke for the magnet system. The following aspects must be taken into consideration:

• the magnetic stray field must be suppressed to the cardiac pacemaker level,• the internal magnetic field and its homogeneity should not be disturbed,• the additional forces onto the coils must not be destructive, and• the magnetic shielding must deal with the limited space conditions.

We will show that for experimental reasons, the magnet geometry is non-axisymmetric and there-fore has to be simulated in three dimensions. In order to reduce the computing time and, at thesame time, increase the numerical accuracy, we simulated only one half of the geometry by takingadvantage of the symmetry of the magnet and its shielding. The design of the magnetic shieldingfor PERC will be presented in this poster: The finite element method (COMSOL Multiphysics) hasbeen used to determine the most suited geometry for the magnetic shielding. Various geometriesand combinations of shielding materials of non-linear permeability have been simulated.

149


Strangeness Production in p− p Collisions at FOPIKatharina Isepp1

1Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria

According to theoretical predictions [1] deeply bound kaonic states are possibly created inproton-proton collisions. To verify them experimentally the FOPI detector at GSI [2] investigateda 3.1 GeV proton beam targeting on liquid hydrogen in 2009. In this reaction the Λ(1405) resonanceplays a special role. It can be interpreted as a pK− bound state which serves as a doorway state toproduce the deeply bound state ppK−. This state decays eventually with a large branching ratiointo a Λ hyperon and a proton. The poster presents the reconstruction of the Λ involved in thep+ p→ pK+Λ final state from its decay products π− and p.

[1] Y. Akaishi and T. Yamasaki, PRC 76, 045201, 2007[2] www.gsi.de / www-fopi.gsi.de


Proton Spectroscopy with PERCMichael Klopf1, Jacqueline Erhart1, Gertrud Konrad1, Hartmut Abele1


The PERC collaboration will perform high-precision measurements of angular correlations inneutron beta decay at the FRM II in Garching, Germany. The new facility PERC, a novel sourceof neutron decay products, is designed to improve the sensitivity of neutron decay studies by oneorder of magnitude. Depending on the angular correlations studied with PERC, the analysis of theextracted decay electrons and protons is performed with different and specialized detectors. As faras protons are concerned, PERC will feed a charged particle spectrometer, for instance an adaptedspectrometer which can partially be based on the aSPECT detection system. The analysis of thedecay protons is based on a precise energy measurement, by means of an electrostatic filter or bytime-of-flight measurement. Then, e.g., the electric potential between the decay and filter regions(0 – 780 V) has to be known with an accuracy of better than 10 mV. Up to the completion ofthe PERC instrument, systematic uncertainties in the analysis of decay protons are investigatedwith the aSPECT spectrometer. In order to, e.g., avoid electrical breakdowns initiated by anddischarges due to field emission from the high voltage electrodes, the high voltage system has beenredesigned. Besides the physics motivation, the optimization of the aSPECT spectrometer, thedetection concept and the dominant systematic uncertainties for PERC will be presented in thisposter.

150


Local-Duality QCD Sum Rules for Pseudoscalar-Meson FormFactors

Wolfgang Lucha1, Irina Balakireva2, Dimitri Melikhov1

1Osterreichische Akademie der Wissenschaften, Nikolsdorfer Gasse 18, 1050 Wien, Austria2Moscow State University, SINP, 119991, Moscow, Russia

Utilizing the local-duality formulation of QCD sum rules, we scrutinize anew some strangefindings for the charged-pion elastic form factor and for the form factor describing the neutral-piontransition to one real and one virtual photon within a broad range of momentum transfers. Theuncertainties of the local-duality approximation to the QCD sum-rule formalism are estimated byanalyzing, in parallel to QCD, quantum-mechanical potential models, where the exact form factorsmay be easily obtained by solving the Schrodinger equation and then compared with the local-duality sum-rule outcomes. From these studies, we expect the accuracy of the predictions of simplelocal-duality models to improve very fast with increasing momentum transfer and thus regard largedeviations from the elastic pion form factor’s local-duality behaviour, recently predicted by somehadron-structure models, as rather unlikely. Furthermore, in startling contrast to the excellentagreement of the local-duality results for the (η, η′, ηc) → γ + γ∗ transition form factors, recentBABAR measurements of the π → γ + γ∗ transition form factor imply inexplicable local-dualityviolations which even rise with momentum transfer.


Investigations of negative ion formation in Middleton typeion sources

Martin Martschini1, Pontus Andersson1, Oliver Forstner1, Robin Golser1, Dag Hanstorp2,Anton Lindahl2, Johan Rohlen2

1University of Vienna, Wahringer Strasse 17, 1090 Wien, Austria2University Gothenburg, Fysikgrand 3, Plan 8 rum F8032, SE-412 96 Goteborg, Sweden

Since 1977, sputter ion sources of the Middleton type have been the main tool used to createstable, intense negative ion beams for Accelerator Mass Spectrometry (AMS). Nevertheless, thetheory behind negative ion formation is not fully agreed upon and recipes for high current outputdiffer from lab to lab. A better understanding of the sputtering process is expected to allow furtheroptimization of negative ion sources and thereby enhance the abundance sensitivity of AMS forseveral radioisotopes. As part of the work in trying to unravel the mechanisms of hard sputteringin a cesium rich environment, we have resolved the spectrum of blue light emitted from the cathoderegion during high current output. A fiber coupled spectrometer was used to detect light in thewavelength region 200 to 1100 nm. When sputtering a carbon target, the emitted light consistsalmost entirely of persistent lines from neutral cesium. To our surprise, the spectra from aluminumor copper targets showed also persistent lines from Cs+. In another experiment, the effect of contin-uous wave laser light directed onto the cathode surface was studied. Independent from wavelength,the laser light induced a significant change in oxygen, sulfur and chlorine negative ion productionfrom a AgCl target. Approximately 100 mW of laser light changed the elemental composition ofthe ion beam by one order of magnitude. This technique was successfully applied during a regularAMS measurement of 36Cl at VERA (Vienna Environmental Research Accelerator). The physicsbehind the effect still requires further investigations.

151


Elektronen-Energie-Detektion fur PERCMartin Moser1, Thomas Cervinka1, Jacqueline Erhart1, Gertrud Konrad1, Sebastian Maaß1,

Xiangzun Wang1, Hartmut Abele1


Das freie Neutron zerfallt auf Grund der schwachen Wechselwirkung uber den Betazerfall in einProton, ein Elektron und ein Elektron-Antineutrino. Uber die Winkelkorrelationen dieser Teilchenist es moglich, die Gultigkeit des Standardmodells der Teilchenphysik zu uberprufen bzw. zu erweit-ern. Das neue Instrument PERC ermoglicht es, die Korrelationskoeffizienten zwischen dem Neutro-nenspin und den Impulsen der Zerfallsprodukte in noch nie dagewesener Prazision zu messen; da dieZerfallsrate bei 106 liegen wird. Das zum Einsatz kommende Elektronenspektrometer basiert aufdem von unserer Arbeitsgruppe an der Universitat Heidelberg entwickelten und vom Atominstitutder Technischen Universitat Wien, zur Erhohung der Effizienz, adaptierte Spektrometer PERKEO3.In Wien wird einer der Detektoren von PERKEO3 charakterisiert und dessen fur die Elektronen-spektroskopie relevanten Systematiken untersucht. Das Ziel ist Elektronenspektroskopie auf 10−4

Niveau. Die Energiedetektion erfolgt dabei uber Szintillatoren mit Photomultiplierauslese, auf de-nen besonderes Augenmerk liegt: Auf Grund ihrer kurzen Auslesezeit und hohen Zeitauflosungist es moglich, bei besonders hohen Zahlraten zu arbeiten, was gerade fur PERC von großer Be-deutung ist. Zusatzlich wird auch die Stabilitat des Messsystems erhoht und charakterisiert, umeine mogliche Variation von Zerfallskonstanten zu bestimmen. Erganzend zu den direkten Sta-bilitatstests mit Eichproben werden auch Monte Carlo Berechnungen durchgefuhrt, die sowohl dasRuckstreuverhalten sowie die Elektronenabsorption und -transmission aus dem Szintillationsmate-rial als auch dem Detektorgehause aus Edelstahl untersuchen. Diese Simulationen werden mittelsder speziell dafur entwickelten Simulationssoftware CASINO durchgefuhrt.


A new very-large Perfect Crystal Neutron InterferometerThomas Potocar1, Ulrich Kuetgens2, Michael Zawisky1, Harald Huber1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria2Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

The different stages of the machining of the largest crystal interferometer are presented. Pathlength, beam separation and enclosed beam area are exceeding, by far, the dimensions of hithertoprepared interferometer crystals. Due to its large dimensions and the steplike cut middle platesit can be used as multi-purpose instrument: The interferometers lower part serves as a compact,extremely sensitive angle measuring device. The upper part is mainly used for gravitation experi-ments where three interference loops can be used with the same interferometer.

This research was funded by the Austrian Science Fund (FWF): Project I530-N20.

152


Global Trigger Upgrade project for the CMS experiment atLHC

Babak Rahbaran1

1Osterreichische Akademie der Wissenschaften, Nikolsdorfer Gasse 18, 1050 Wien, Austria

The electronics of the first Level Global Trigger (GT) of CMS is the last stage of the Level-1trigger system. At LHC up to 40 million collisions of proton bunches occur every second, result-ing in about 800 million proton collisions. The CMS Level-1 Global Trigger, a custom designedelectronics system based on FPGA technology and the VMEbus system, performs a quick on-lineanalysis of each collision every 25 ns and decides whether to reject or to accept it for furtheranalysis. Various parts of the CMS trigger and in particular the Level-1 hardware trigger will beupgraded to cope with increasing luminosity, using more selective trigger conditions at Level-1 andimproving the reliability of the system. The CMS trigger group of the Institute of High EnergyPhysics in Vienna (HEPHY) is involved in the Level-1 trigger of the CMS experiment at CERN.As part of the Trigger Upgrade, the Level-1 Global Trigger will be redesigned and implemented inMicroTCA based technology, which allows engineers to detect all possible faults on plug-in boards,in the power supply and in the cooling system. The upgraded Global Trigger will be designed tohave the same basic categories of functions as the present GT, but will have more algorithms andmore possibilities for combining trigger candidates. Additionally, reconfigurability and testabilitywill be supported based on the next system generation.


Recent Advances in Accelerator Mass Spectrometry of theactinides at the Vienna Environmental Research Accelerator

Stephan Winkler1, Peter Steier1, Alfred Priller1, Josef Buchriegler1, Robin Golser1

1University of Vienna, Wahringer Strasse 17, 1090 Wien, Austria

Actinides have wide application in environmental science, both as tracer and as dating tool.Accelerator Mass Spectrometry (AMS) has been shown to allow for the lowest isotope ratio de-tection limits for actinides. However, careful design of the spectrometer and an understanding ofbeam and atomic physics is required to achieve the detection limits required for the measurementof naturally occurring 236-U or the artificially produced plutonium isotopes beyond mass 240 inthe general environment. We present our latest developments and improvements at the ViennaEnvironmental Research accelerators heavy isotope beam-line and give also a wider perspective onthe design of an ideal heavy-ion AMS system.

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POS-21, FKP & NESY, Wed, 17:45

The Impact of Temperature and Electric Fields onSurfactant-Molecules - an in-situ SAXS StudyJohanna Akbarzadeh1, Sylvia Flaig2, Nicola Huesing2, Herwig Peterlik1

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria2Paris-Lodron University Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria

The combination of different synthetic strategies such as sol-gel processing together withtemplating approaches have been proven to be an effective method in the preparation of longrange ordered mesoporous materials. However, for many applications (e.g. microelectronic devices,membranes. . .) not only highly ordered mesopores but also a precisely defined pore orientationwould be desirable. One way to achieve such highly oriented mesopores is the exposure of the sam-ple to an electric field during the sol-gel process. Electric field induced orientation of mesoporeshas already been reported in literature, for example Ku et al. have shown that the application ofan low-strength electric field in the preparation of surfactant - templated nanoscopic silica fibersleads to oriented nanochannels with both micrometer and nanometer levels of hierarchy. Trau etal. have demonstrated that the use of high-strength electric fields in the production of nanoscopicpatterned thin films leads to nanochannels oriented parallel to the applied electric field. In thiswork we investigate the temperature dependence of different (anionic, cationic and zwitterionic)surfactant molecules in an external electric field ranging from some kV/m up to 1 MV/m. Thesemolecules will further serve as a template phase in the sol-gel process to produce long range or-dered and highly oriented mesoporous materials. The structural change on the nanometer level isfollowed in-situ by small-angle X-ray scattering.


X-ray strain microscopy on Ge micro-bridgesTanja Etzelstorfer1, Martin Suess2, Gustav Schiefler3, Ana Diaz3, Hans-Christian Sigg3,

Vincent Jaques4, Daniel Chrastina5, Giovanni Isella5, Ralph Spolenak2, Julian Stangl1

1Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria2ETH Zurich, Wolfgang-Pauli-Strasse 16, 8093 Zurich, Switzerland

3Paul Scherrer Institut Paul Scherrer Institut, 5232 Villigen PSI, Switzerland4ESRF, 6 Rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9, France

5Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy

In the SiGe system optical emitters are difficult to realize due to the indirect band gap. Em-ployment of tensile strain in Ge is a promising route to shift to the indirect transition. Technicalrealization of required strain values of a few per cent is, however, rather difficult and requires com-plex strain microscopy. In this study micro bridges are investigated, where strain enhancement inabout 0.2 % tensile pre-strained Ge layers grown on Si is achieved. The transfer of an electron-beam written pattern leads to force field concentration. By tuning the geometry of the structure,the strain may be enhanced to levels high enough to convert the indirect band gap to a direct one.The strain distribution in tensile strained Ge micro-bridges is studied by X-ray nano-diffraction,which is an excellent tool to spatially resolve the 3D displacement field. The strain mapping ofthe transition regions between the centre of the bridge and the wide feeder arms was performedat beamline ID01 of the ESRF. Single bridges were raster-scanned in real space, while Ge Braggpeaks were recorded in 3D. This allows to map Bragg peaks with a resolution close to the beamsizeand thereof to quantify the strain in the bridges with a spatial resolution of around 300 nm. Theseresults, together with finite-element calculations, will be used to understand strain limitations of Geand hence its lasing potential, establishing an important milestone in the development of Si-CMOScompatible laser sources.

154


Magnetic study of iron oxide nanoparticles dispersed withinporous silicon

Petra Granitzer1, Klemens Rumpf1, Puerto Morales2, Peter Polt3, Michael Reissner4

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2CSIC Madrid, Serrano, 117. 28006 Madrid, Spain

3Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria4Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Wien, Austria

Iron oxide nanoparticles (NPs) of 3.8, 5 and 8 nm have been infiltrated into the pores of poroussilicon. The aim is to create a superparamagnetic (SPM) nanocomposite system with maximizedmagnetic moment. Therefore the particle size versus the superparamagnetic behaviour has beenfigured out. The blocking temperature TB which indicates the transition between SPM behaviourand blocked state is not only dependent on the particle size but also the magnetic interactionsbetween them which can be varied by the distance between the particles. Thus a modification, onthe one hand of the pore-loading and on the other hand of the porous silicon morphoplogy results ina composite material with a desired TB. Because both materials, the mesoporous silicon matricesas well as the Fe3O4-NPs offer low toxicity the system is a promising candidate for biomedicalapplications as e.g. magnetic field guided drug delivery.


High Resolution X-Ray Diffraction Studies on Arrays of SiGeIslands

Nina Hrauda1, Jianjun Zhang2, Heiko Groiss1, Tanja Etzelstorfer1, Vaclav Holy3, Julian Stangl1,Gunther Bauer1

1Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria2IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

3Charles University Prague, Ke Karlovu 5, Praha, 12116, Czech Republic

The Si-Ge material system is an interesting topic for both for basic research advanced nanoscaledevices as well. To speed up silicon-based transistors both tensile (for n-type) or compressive strain(for p-type) can be applied to the Si-channel of MOSFETs, depending on the setup. Several ap-proaches exist to induce that strain like the application of stressed nitride layers or the use of planarSiGe stressor structures. Our research focuses on the use of epitaxially grown 3D SiGe islands thatoccur due to the lattice mismatch of 4.2% between Si and Ge. We present studies based on X-raydiffraction and finite element method modeling including both dome- and barn-shaped SiGe islandsgrown on prepatterned Si(001) substrates. The overgrowth of highly relaxed SiGe islands with Siresults in tensile strain in the Si layer above the buried island. The amount of strain depends onseveral factors such as the composition of the buried island, its shape, as well as the thickness ofthe capping layer. Growing SiGe islands in a closely-spaced configuration can be used to inducecompressive strain in the sections of the Si cap layer situated between those islands.

155


Proton implanted silicon wafers investigated by electronbeam induced current measurements

Stefan Kirnstotter1, Peter Hadley1, Werner Schustereder2, Martin Faccinelli1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Infineon Technologies Austria AG, 9500 Villach, Austria

Electron Beam Induced Current (EBIC) is an analysis method used in a Scanning ElectronMicroscope (SEM) to investigate buried junctions or defects in semiconductors. During an EBICmeasurement, the electron beam enters a semiconductor and generates electron-hole pairs. If thecharge carriers diffuse into a region where there is a built-in electric field, such as a pn junction ora Schottky contact, charge separation will occur and a current will flow. This is similar to whathappens in a solar cell except in an EBIC measurement the electron-hole pairs are generated bythe electron beam instead of by light. We have used EBIC to investigate proton implanted siliconwafers with implantation doses from 1 × 1013 p+/cm2 to 1 × 1015 p+/cm2 and with implanta-tion energies from 500 keV to 5 MeV. The implantation introduces vacancies, silicon interstitials,and hydrogen into the crystal. The sample is then annealed in the temperature range from roomtemperature to 1000◦C and defect complexes form. The microscopic structure of these defect com-plexes is not completely understood. There is a class of oxygen-vacancy defect complexes calledthermal donors that are known to act as donors in silicon. Since electron-hole pairs recombine atdefects, the EBIC signal is decreased if the charge carriers have to diffuse past defects on their wayto the measurement contacts.


Towards kinetic Monte-Carlo simulations with ab initioaccuracy

Martin Leitner1, Tobias Kerscher1, Stefan Muller2, Raimund Podloucky1

1University of Vienny, Sensengasse 8/7, 1090 Vienna, Austria2Hamburg University of Technology, Denickestrasse 15 (K), 21073 Hamburg, Germany

For the Ni–Pt and Fe–Cu alloy system we present the first steps towards kinetic Monte-Carlo(KMC) simulations with ab initio accuracy. Many body interactions which describe the energeticsof both the local minima and migration states are included by cluster expansions (CE) in the frame-work of the UNCLE code [1]. In this model approach single atoms jump to vacant nearest-neighborsites and have to overcome configuration dependent migration barriers. According to transitionstate theory (TST) jump rates are then derived by the energy difference between initial and saddlepoint state. The KMC simulations require a) vacant lattice sites, which enforce a ternary CE fora binary compound, and b) the configuration dependent height of the saddle points, which have tobe calculated and included in the CE. We discuss different aspects of jump profiles in the respectivesystems computed by density functional theory (DFT) calculations.

The support of FWF project 4110 (ViCoM) is acknowledged.

[1] D. Lerch et al., Modelling Simul. Mater. Sci. Eng. 17 (2009), 055003

156


Wood templated inorganic nanoporous materials: Formationand water adsorption studied by in situ SAXS experimentsRoland Johann Morak1, Gerhard Fritz-Popovski1, Daniel Van Opdenbosch2, Cordt Zollfrank2,

Barbara Aichmayer3, Oskar Paris1

1Montanuniversitat Leoben, Franz-Josef Strasse 18, 8700 Leoben, Austria2Technische Universitat Munchen, Schulgasse 16, 94315 Straubing, Germany

3MPI of Colloids and Interfaces, Wissenschaftspark Potsdam-Golm, 14424 Potsdam, Germany

Wood is an abundantly occurring hierarchically structured composite material. It consistsof fibrils of diameter 10-20 nm, which are embedded into a lignin matrix. These fibrils consiststhemselves of cellulose microfibrils of diameter 2-3 nm embedded in surrounding hemicelluloses. Inthis work, wood was used as a template in order to obtain inorganic materials with chiral nano-pores. The necessary preparation steps are deliginification, cell-wall modification with maleic acidanhydride, infiltration with tetraethyl orthosilicate (TEOS) and calcination. We studied the trans-formation of the composite material to porous silica using synchrotron radiation for in-situ SAXSexperiments during the calcination of the sample. The nano-structure changed progressively fromfibrils with a nearly homogeneous electron density and with a diameter of 10-20 nm to fibrils withdiameters of 8-10 nm. Modeling of the results revealed a two step process. The hemicelluloses dis-integrate at 200-300 ◦C and amorphous silica is formed. The cellulose fibrils, which are embeddedin amorphous silica after this step, are still intact. At 300-400 ◦C the cellulose degrades and leavesnanometer sized pores within the silica. The gas adsorption properties of these materials were stud-ied further by in-situ adsorption experiments with SAXS and compared to results obtained fromgravimetric measurements. The gravimetric measurements feature the existence of accessible poreswhereas the scattering parameters imply a change of the material structure during a sorption cycle.


Polarisation-dependent Raman characterization of stibnite(Sb2S3)

Maurizio Musso1, Paolo Sereni1, Kurt Krenn2, Peter Knoll1, Peter Blaha3, Karlheinz Schwarz3,Gunther Schmidt3

1University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria2University of Graz, Universitatsplatz 2, 8010 Graz, Austria

3Vienna University of Technology, Getreidemarkt 9/165-TC, 1060 Vienna, Austria

Single crystal samples of Stibnite (Sb2S3), a naturally occurring sulfide mineral with semi-conducting properties (band gap 1.72 eV), were studied by polarization-dependent Raman spec-troscopic measurements using both visible and NIR laser excitation. In the case of visible laserexcitation at 532 nm (2.33 eV) the laser light was highly absorbed, being the photon energy higherthan the band gap of the semiconductor; measurements at 180◦ scattering geometry (backwardscattering) were therefore only possible. In the case of NIR laser excitation at 1064 nm (1.17eV)the photon energy was lower than the band gap of the semiconductor, the sample therefore resultingtransparent to the excitation line, therefore allowing polarization-dependent measurements both in180◦ and 90◦ scattering geometry. The analysis of the group symmetries yields 10 Ag, 5 B1g, 10B2g, and 5 B3g Raman active vibrational modes. The comparison of the corresponding Ramanfrequencies calculated using the ab-initio WIEN2k and PHONON codes [1] with our experimen-tal values obtained both in 90◦ and in 180◦ scattering geometries shows overall good qualitativeagreement, although the discrimination between Ag and B2g modes, and that between B1g andB3g modes in the experimental spectra is still challenging, since the number of bands is the samefor both modes, and the calculated band positions quite close.

[1] P. Blaha, K. Schwarz, G.K.H. Madsen, D. Kvasnicka, J. Luitz, WIEN2k (2001) ; K.Parlinski,Software PHONON, Cracow (2002).

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Numerical simulations of scanning gate experiments in thequantum Hall effect regime

Josef Oswald1

1Montanuniversitat Leoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria

In combination with the scanning gate microscope (SGM), the quantum Hall (QH) systemprovides a possibility for studying transport in coherent electronic systems. A gate tip introducesa local distortion and the response of the device is recorded versus tip position. We use a non-equilibrium network model (NNM) for transport and combine it with a full quantum mechanicalmany particle calculation of the disordered electron system on the Hartree-Fock level. The dis-ordered potential of the electronic system can be understood as a native random arrangement ofquantum dots and quantum point contacts, which interact in a complex way. Either caused bya sweeping magnetic field or by moving a biased gate tip, any changes of the quantum states aresensitively monitored also by the Hartree part of the self-consistent Hartree-Fock solution, whichmodulates the transmission behaviour of the involved saddle potentials. That is sensitively de-tected by our network model and results e.g. in resistance fluctuations. We present preliminarysimulation results for both, magneto resistance fluctuations and responsivity maps for a movinggate tip. The importance of the electron-electron interaction in our simulations is demonstrated byturning on and off the Hartree part of the Hatree-Fock solution for the screened random potential.

Financial Support: Austrian Science Foundation FWF Project.Nr. P19353-N16


The nanomechanics of feather keratin studied by small-angleX-ray scattering

Silvia Pabisch1, Ingrid Weiss2, Helmut Kirchner2, Stephan Puchegger1, Herwig Peterlik1

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria2INM – Leibniz-Institut fur Neue Materialien gGmbH, Campus D2 2, 66123 Saarbrucken, Germany

Feather keratin is a highly conserved protein of 98 amino acids synthesized intracellularly inaves. In the cortex of the tail covert feathers of the peacock it forms a crystalline structure, heldtogether by disulfide bonds between the nine cysteines of the molecule. Despite the biologicalimportance of the molecule, its spatial structure has not yet been determined. Fraser and Parryproposed a crystallographic arrangement of beta-barrels and relegate the N-terminus and the C-terminus to an amorphous matrix, akin to the situation in silk [1]. Therefore, in-situ tension andcompression tests were made to investigate the changes in axial and lateral direction. Nanoscopi-cally a pronounced structural asymmetry between tension and compression rules out a dihedral axisnormal to the fibril direction, and indicates a strong clip-like polarization of the molecule. Basedon these X-ray diffraction data from Pavo cristatus feathers, a model is presented for the axial andlateral arrangement of the molecule in feather keratin, which integrates biochemical structure andmechanical experiments.

[1] R. D. B. Fraser, D. A. D. Parry, J. Struct. Biol. 162 (2008) 1-13.

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Fabrication and optical characterization of CdSe quantumdots

Manuel Pacheco1, Carlos Rudamas1

1Universidad de El Salvador, Escuela de Fısica, 25 San Salvador, El Salvador

In this paper we present results of the optical characterization of CdSe quantum dots (QDs)fabricated using the thermal decomposition technique. For the preparation of the samples we usedtwo precursor solutions to generate the reaction which was initiated at a temperature of 225◦C. Tenaliquots were collected at different time intervals during the synthesis. The optical properties ofthese samples have been studied by absorption spectroscopy and photoluminescence spectroscopy.The maximum of the absorption bands show a shift to lower energies from 2.95 eV to 2.35 eV asthe size of the quantum dots increase. Photoluminescence bands also exhibit a similar shift from2.66 eV to 2.17 eV. Stokes-Shifts from 20 nm to 40 nm were estimated. The full width at halfmaximum (FWHM) obtained for the photoluminescence bands ranges from 30 nm to 45 nm, whichindicates a very good mono-dispersivity of the samples. To calculate the size of the quantum dotswe used the effective mass approximation and the absorption spectra for each sample. Quantumdot radii obtained by using this model vary from 1.73 nm to 2.49 nm.


Defects in an iron-nickel meteorite examined with positronsPeter Parz1, Matthias Leitner1, Wolfgang Sprengel1, Werner Puff1


A typical iron-nickel meteorite (Gibeon) with a composition of Ni 7,93 wt-%, Co 0.41 wt-%, P0.04 wt-%, 91.62wt-% Fe and small amounts of carbon, was investigated by positron annihilationmethods (positron lifetime spectroscopy and coincidence Doppler broadening). This meteorite ex-hibits the typical Widmanstatten structure, a two-phase microstructure of Fe-rich Kamacite andNi-rich Taenite, which is formed due to unique cooling rates of about approximately 35K perone million years. Upon the low cooling rates in space and the formation of the Widmanstattenstructure, the meteorite sample was expected to be in equilibrium condition and free of defects.However, a high mean positron lifetime was observed, which derives from open volume defects.The meteorite samples were then gradually heated in a high-vacuum furnace, cooled down to roomtemperature and probed. The temperature treatment leads to a decrease of the mean positronlifetime, as well as a gradual evolution of the 2d-DB spectra towards pure iron. This results lead tothe conclusion, that in the progress of the formation of the Widmanstatten structure open volumedefects are introduced. Upon heat treatment these defects start to dissolve and do not re-appear.We attribute these open volume defects to misfit dislocations between the Kamacite (Ni-poor) andTaenite (Ni-rich) structures.

159


Negative thermal expansion of carbon crystallites measuredin single carbon fibres

Harald Rennhofer1, Stephan Puchegger1, Silvia Pabisch1, Stefan Siegel2, Chenghao Li2,Oskar Paris3, Herwig Peterlik1

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria2Max-Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany3Montanuniversitat Leoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

In-situ X-ray scattering experiments on single carbon fibres have been performed at BESSYBerlin. The structural response to simultaneous application of temperature and load was studiedby Small- and Wide Angle X-ray Scattering, respectively. In this work the thermal expansion ofthe crystallites in the carbon fibres (MPP and PAN) is presented. At temperatures below 800 ◦Cnegative thermal expansion in the graphite planes was measured for the MPP fibres. The relation-ship with the macroscopic thermal expansion is given by the misalignment of the crystallites withrespect to the fibre axis i.e. the degree of graphitization.


Toward polarisation entangled photon pairs from microcavityexciton polaritons

Mathias Sassermann1, Lukas Einkemmer1, Patrick Mai1, Zoltan Voros1, Gregor Weihs1,Tobias Zederbauer2, Hermann Detz2, Aaron Maxwell Andrews2, Gottfried Strasser2,

Christian Schneider3, Andreas Loffler3, Sven Hofling3, Alfred Forchel3, Stefano Portolan4

1University of Innsbruck, Technikerstrasse 13, 6020 Innsbruck, Austria2Vienna University of Technology, Karlsplatz 13, 1040 Vienna, Austria

3Universitat Wurzburg, Am Hubland, 97074 Wurzburg, Germany4Institut Neel-CNRS, 25 avenue des Martyrs, BP 166 38042 Grenoble, Cedex 9, France

The strong coupling of photons and quantum well excitons in semiconductor microcavities leadsto the formation of new quasi particles called polaritons. Due to their peculiar dispersion curve andthe convenient experimental accessibility microcavity polaritons have gained considerable interestin the recent years. Polariton states can be selectively populated by choosing the excitation angleand the wavelength of the excitation laser. After a lifetime of a few picoseconds the polariton decaysand a photon is emitted from the cavity. This photon carries the whole information on the previouspolariton state.So far the focus in this field was mainly on polariton lasing, BEC, non-classical corre-lations and collective phenomena in semiconductors. Recent theoretical studies suggested utilizingpolariton-polariton scattering for generation of entangled photon pairs. S.Portolan et al.(EPL 8820003 (2009)) have proposed a scheme based on polariton four-wave mixing in order to generatepolarisation entangled photon pairs. The experimental implementation of this scheme requirestwo pump beams with different incidence angles and wavelengths. For this purpose we employ amultidimensional spectroscopy setup based on two spatial light modulators (Appl. Phys Lett. 100072109 (2012)). As a first step towards polariton entanglement parametric polariton scatteringunder two-colour excitation has to be established. In this contribution we will show first results onsuch scattering experiments and will demonstrate the feasibility of the proposal in Portolan et al.The experimental results will be compared to detailed numerical simulations based on a Langevinmaster equation approach.

160


Elektromagnetische Levitation – BeruhrungsfreieUntersuchung von flussigem Metall an der TU Graz

Alexander Schmon1, Kirmanj Aziz1, Gernot Pottlacher1


Flussiges Metall als Untersuchungsobjekt stellt besonders hohe Anspruche an den experi-mentellen Messaufbau um dem Prinzip der Interaktionsreduktion als Messvoraussetzung gerecht zuwerden. Die Methode der Elektromagnetischen Levitation ermoglicht eine tiegelfreie Bestimmungvon thermophysikalischen Eigenschaften metallischer Schmelzen. Derzeit wird der Aufbau einerentsprechenden Apparatur am Institut fur Experimentalphysik der TU Graz fertiggestellt. Dabeiwerden durch ein inhomogenes elektromagnetisches Hochfrequenzfeld Wirbelstrome im Proben-material erzeugt, welche aufgrund der ausgeubten Lorentzkraft ein frei schwebendes Positionierender Probe ermoglichen und gleichzeitig zu einem Aufheizen des Probenmaterials bis in die flussigePhase fuhren. Die Probentemperatur wird optisch durch pyrometrische Messung bestimmt undgleichzeitig die Probengeometrie mittels zweier High-Speed-Kameras aufgezeichnet. Unter Verwen-dung dieser Messgroßen wird die Bestimmung von Dichte und Oberflachenspannung der Probe inAbhangigkeit von der Temperatur ermoglicht.

Das Projekt Messung von Oberflachenspannung und Dichte mittels Levitation wird vom Fonds zurForderung der wissenschaftlichen Forschung (FWF) gefordert - Projekt P 23838-N20


Polarization-dependent Raman characterization of Stibnite(Sb2S3) in the temperature-range 290K-77K

Paolo Sereni1, Maurizio Musso1, Stefan Volgger1, Christoph Oberauer1, Peter Knoll2

1University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria2University of Graz, Universitatsplatz 5, 8010 Graz, Austria

A complete set of measurements of the polarization-dependent Raman spectra of Stibnite(Sb2S3) in the temperature range from 290K to 77K are here presented and compared with thoseobtained in our previous activities [1]. The used equipment consisted of a 1064 nm polarized laserexcitation, an FT-Raman spectrometer (Bruker IFS66 + FRA106) and an Optistat LN2 BathCryostat (Oxford Instruments).

[1] P. Sereni et al., AIP Conference Proceedings 1267, 1131-1132 (2010)

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Modeling disorder in self-assembled monolayers withembedded dipoles

Manuel Vieider1, Luca Muccioli2, Otello Roscioni2, Egbert Zojer1, Michael Zharnikov3,Claudio Zannoni2, Martin Stolterfoht1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Universita di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy

3University of Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany

We present a study using several techniques to simulate self assembled monolayers (SAM) onthe Au(111) substrate. Accurate quantum mechanical simulations were used to parameterize thecharge distribution on the molecules and to estimate the charge transfer to the gold surface causedby the binding of sulfur atoms. The results delivered the inputs for atomistic molecular dynamicsimulations carried out with the LAMMPS code. The intermolecular interactions were described bythe CHARMM27 force field, while for the interaction of the molecules and the gold atoms differentforce fields were tested. The main focus of this work is to provide an accurate description of themorphology of alkylthiols with and without a mid-chain ester functionalization. This particularclass of molecules was chosen because the ester group provides an intramolecular electric dipolemoment at a certain distance from the surface. We calculated the distribution of dipole orientationsfrom equilibrated structures of monolayers in order to estimate the net-potential shift induced bythose dipoles. Also, different surface coverages have been simulated to investigate the thermody-namic mechanisms of SAM islands formation and to quantify the intrinsic structural disorder bycomputing various order parameters.

POS-38, GEP, Wed, 17:45

Alfred Wegener: Second Expedition to Greenland - Aphotographic window to the past

Martin Leitner1, Sabine Tschurtz1, Gottfried Kirchengast1, Heinrich Kranzelbinder2, B. Prugger2,Reinhard Krause3, M. Kalliokoski4, Ester Thorhallsdottir5

1University of Graz (WEGC UniGraz), Leechgasse 25, 8010 Graz, Austria2Steiermarkisches Landesarchiv, Karmeliterplatz 3, 8010 Graz, Austria

3Alfred Wegener Institute, Columbusstrasse, 27568 Bremerhaven, Germany4University of Turku, FI-20014 Turku, Finland

5Fjolbrautaskli Snæfellinga, Iceland

On several expeditions to Greenland, Alfred Wegener (1880-1930) collected scientific data andtook pictures on glass plates from landscapes and glaciers, the expedition equipment, the peopleand animals taking part on the expeditions as well as physical phenomena as dust storm, clouds orspherical light phenomena. Until the tragic end of the expedition in 1930, Wegener was professorat the University of Graz, and such a stock of about 300 glass plates stayed there. Chronologicallythe plates show the Danmark Expedition 1906-1908, the crossing of Greenland expedition withstop in Iceland 1912-1913, and the German Greenland Expedition 1929-1930. This presentationgives an overview of pictures and dates from the Second Greenland Expedition, leaded by J.P.Kochin 1912-1913. The aim of our work is to digitize all the plates for further studies. We present aselection from the second Greenland expedition, with the stopover in Iceland. For those made atIceland in 1912 we present a comparison between past pictures an new one from the same viewingpoint made in 2011.

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POS-39, LHS (PUS), Wed, 17:45

Kinder reisen durch die WissenschaftHans Eck1, Sabine Hirschmugl-Gaisch2

1Kirchliche Padagogische Hochschule Graz, Lange Gasse 2, 8010 Graz, Austria2Kindergarten Rosental an der Kainach, Horggasstrasse 50, 8582 Rosental

“Kinder reisen durch die Wissenschaft” ist ein Gemeinschaftsprojekt der Neuen MittelschuleVoitsberg, des Kindergarten Rosental a. d. K. , dem “Offenen Labor Graz” in Kooperation mit der“7. fakultat” der Karl-Franzens-Universitat Graz und dem Interdisziplinaren Zentrum fur Fachdi-daktik der Padagogischen Hochschule Steiermark, mit dem Ziel, Kindern, wie Jugendlichen einenkreativ-interessanten und lustvoll-aktiven Zugang zu den unterschiedlichen naturwissenschaftlichenDisziplinen und Fachrichtungen zu ermoglichen. Unter dem Motto: “Große helfen Kleinen” wer-den in diesem Projekt Forschungsteams bestehend aus je einem Kindergarten-Kind und einem/erSchulerIn der Neuen Mittelschule gebildet, die auf dieser Reise durch die verschiedensten wis-senschaftlichen Institutionen gemeinsam Aufgaben losen, Experimente durchfuhren und dabei dieMoglichkeit haben, ihre eigenen Forschungen zu betreiben. Betreut und angeleitet werden dieKinder und Jugendlichen in den einzelnen Modulen dabei jeweils von einem Wissenschaftler, oderSpezialisten seines Faches und einem/er StudentIn der naturwissenschaftlichen Fachrichtung. DenAuftakt der “Reise durch die Wissenschaften” bildete der erste “Molekulare Kochkurs fur Kinder-gartenkinder” in Begleitung von SchulerInnen der NMS- Voitsberg unter dem Motto: “Es dampftaus Kochtopf, Mund und Nase” an der NMS-Voitsberg. Unter der Anleitung von 2- HaubenkochHeinz Preschan, Dr. Helmut Jungwirth (Offenes Labor Graz) und einer Studentin der Biowis-senschaften wurden in 3 Teams nicht nur dampfender, flussiger Stickstoff und seine Auswirkungenauf Popcorn, Petersilie und Basilikum erforscht, sondern auch Joghurt-Bomben, Chilli-Rosmarin-Lollies und Kurbiskernschokolade hergestellt und mit großem Genuss gemeinsam verkostet.


Forschendes Lernen als Methode der KompetenzforderungErich Reichel1, Eduard Schittelkopf1, Veronika Rechberger1

1Padagogische Hochschule Steiermark, Hasnerplatz 12, 8010 Graz, Austria

Fur den Kompetenzerwerb im Physikunterricht bietet sich das forschende Lernen als hilfreicheLernumgebung an. Es ermoglicht den Lerndenden an geeigneten Experimenten eigene Erfahrun-gen zu machen. Dadurch wird ihr Interesse am Thema geweckt und Raum fur eigene Gedankenund Losungsvorschlage im Unterricht geschaffen. Durch den wiederholten Einsatz im Unterrichtkonnen Teile der Handlungsdimension des osterreichischen Kompetenzmodells vor allem im Bereich“Erkenntnisse gewinnen” abgedeckt werden. Vermittelnder Unterricht, in dem das Wissen als Pro-dukt gesehen, das von der Lehrperson an die Lernenden weitergegeben wird steht dem forschendenUnterricht gegenuber, in dessen Rahmen Wissen als ein Prozess gesehen wird, in den der lernendeMensch eintaucht. Im Rahmen von forschendem Unterricht stoßen die Lernenden dabei auf Fra-gen, die bei Durchfuhrung des vermittelnden Unterrichts nie auftreten wurden. Von uns wirdvierphasiger Unterrichtszyklus vorgeschlagen:Phase 1: Den Lernenden wird das Experiment vorgefuhrt und die Protokollierung ihrer Beobach-tungen eingefordert.Phase 2: Die Lernenden fuhren das Experiment selbst durch und fixieren ihre Beobachtungenschriftlich.Phase 3: Die Beobachtungen fuhren zur Formulierung eigener Forschungsfragen.Phase 4: Die Lernenden planen und bearbeiten ihr eigenes Experiment oder eine darauf auf-bauende Variation des Experiments zur Beantwortung ihrer personlichen Forschungsfrage.Fur die Dokumentation der Arbeiten durch die Lernenden und Uberprufung des Lernfortschritteswurde ein eigener Protokollraster entwickelt. Unterrichtsbeobachtungen zeigten in unterschiedlichenKlassen auf unterschiedlichen Schulstufen, dass diese Methode zu mehr Eigenstandigkeit und damiteine Kompetenzsteigerung der Lernenden bewirkt.

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Mit Magnetfeldern horenEngelbert Stuetz1

1Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria

Am Projekt “Mit Magnetfeldern horen” arbeiteten alle Schulerinnen und Schuler zweier siebtenKlassen mit. Ausgangspunkt des Projekts war diese Problemstellung: Trotz ihres Horgerates habenschwerhorige Menschen oft große Probleme, einen Sprecher zu verstehen. Das kann im Kino, imTheater, bei Vortragen oder auch im Klassenzimmer der Fall sein. Schuld daran ist die Funktions-weise des Horgerates. Es macht nicht nur Erwunschtes lauter, sondern auch Nebengerausche. DiePerson hort nur noch ein Stimmgewirr und ist kaum mehr in der Lage, daraus die wichtigen Informa-tionen zu filtern. Die Losung ist eine einfache Anlage, die im Raum aufgebaut wird. Sie ubertragtdie Information mit Hilfe eines Magnetfeldes unmoduliert zur Telefonspule des Horapparates.Das Projekt hatte diese Schwerpunkte:

• Eigenbau einer Induktionsanlage fur einen großen Raum (Physiksaal)• Klarung des physikalischen Hintergrundwissens zur Funktion der Induktionsanlage. Im Wesent-lichen beschaftigten wir uns damit, wie man mit Magnetfeldern das Horen verbessern kann.• Bau von Lern- und Experimentierstationen fur eine Ausstellung “Explorama”. Wichtiger Be-standteil jeder Station war ein von Schulern ausgearbeitetes Arbeitsblatt zum Thema der jeweiligenStation.• Das Explorama in Betrieb: Eine Woche lang konnten Schulklassen fur jeweils eine Stunde dasExplorama buchen. Die Lern- und Experimentierstationen waren dabei von Schulern der Projekt-klassen betreut.• Die Evaluation zum Abschluss des Projekts gab uns Auskunft uber den Erfolg des Projekts unduber Verbesserungsmoglichkeiten bei zukunftigen ahnlichen Projekten an der Hamerlingschule.


Papier erlebenStefanie Anna Tritthart1, Beatrix Janits1

1HS 1 Deutschlandsberg, Schulgasse 16, 8530 Deutschlandsberg, Austria

“Papier ERLEBEN” - das war das Thema des Projektes, an dem von November 2011 bisJanner 2012 an der Hauptschule I in Deutschlandsberg gearbeitet wurde. Nicht nur die Physik-und Chemiestunden in diesem Zeitraum werden den Schulerinnen und Schulern sicherlich langereZeit in Erinnerung bleiben. Auch in den Schwerpunktgruppen der 7. und 8. Schulstufe wurdesehr intensiv an diesem Projekt gearbeitet. Die Highlights waren einerseits das Herstellen vonhandgeschopftem Papier aus unterschiedlichen Materialien und Beigaben wie z.B. das Wespenpa-pier, andererseits die zahlreichen Versuche, die mit diesem Papier gemacht wurden. Es wurdenbeispielsweise verschiedene Papiersorten, darunter auch selbstgeschopftes Papier, auf eine Herd-platte gelegt und genau beobachtet bzw. gemessen wann welches Papier verbrennt. Das “Material”Papier wurde in den Wahlpflichtfachern in den dritten und vierten Klassen unserer Schule unter dieLupe genommen und zur Herstellung unterschiedlichster Dinge verwendet, wie z.B. zum Bau vonPapierflugzeugen und abgestumpften Ikosaedern (besser bekannt als Fußballe) oder zur Herstellungvon in Origami-Technik gefalteten Figuren. Eine Gruppe (Schwerpunkt Kunst) beschaftigte sichdamit, Sessel mit Papiermosaiken zu uberziehen. Im Zuge des technischen Schwerpunkts haben dieSchuler mit Hilfe der Lego Mindstorms c©Roboter das Wort “Papier” auf Papier geschrieben, wobeider Bau des Stifte-Halters und die Programmierung der einzelnen Buchstaben eine ganz schoneHerausforderung fur die einzelnen SchulerInnen war. Der kronende Abschluss war die Prasentationdes Projektes, bei der die Kreativitat unserer Schulerinnen und Schuler gefragt war. Nicht diebei der Projektarbeit entstandenen Produkte allein, sondern auch das neu erworbene Wissen warMittelpunkt der ansprechenden und gelungenen Prasentation.

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POS-43, MBU, Wed, 17:45; This poster will also be presented on Thu. 20th September2012, 16:45 - 16:50;

Ground based MAX-DOAS observations of tropospherictrace gases in San Salvador, El Salvador

Carlos Armando Alberti1, Benjamin Levy Mendoza1, Carlos Rudamas1

1Universidad de El Salvador, Escuela de Fısica, 25 San Salvador, El Salvador

High levels of air pollution in different Central Americas capital cities were reported a fewyears ago, being San Salvador metropolitan area the place with the highest concentration valuesof several pollutants. The high levels of these pollutants, in some measuring points, exceed thelimit values established by the environmental law of the republic of El Salvador and also thoseestablished by EPA and WHO. In this work we report on levels of HCHO, O4 and NO2 obtainedby using ground based Multi-Axis Differential Absorption Spectroscopy (MAX-DOAS) during acampaign performed in San Salvador on February 2011. The experimental set-up used in theDOAS-measurements consists of a home-made-telescope coupled to an spectrometer by using anoptical fiber. The spectral resolution is around 1.2 nm. The diurnal behavior of NO2-dSCD duringthe working days is characterized by an strong increase in the morning. It could be associated toemissions from vehicles during the rush hours. The obtained dSCD values for HCHO are similar tothe obtained by other authors in cities with higher population. The oxygen dimer O4 levels werealso measured in order to estimate the aerosol extinction. Similar trends are observed for HCHOand O4. These results could be explained by a change in the aerosol extinction and meteorologicalconditions.


Bioequivalent Solid-State Dosimetry: Current Trends andFuture Developments

Michael Hajek1


Significant progress in radiobiology has refined our understanding of radiation-induced bio-logical response at the cellular level and challenged the conventional macroscopic description ofradiation action in favour of a nanodosimetric approach, which considers the spatial distributionof energy deposition along the particle track. The empirical correlation of luminescence propertiesof alkali halides and biological endpoints, such as DNA strand breaks in human fibroblasts, openup promising opportunities for bioequivalent solid-state dosimetry. Analysis of the nanodosimetricresponse to different radiation modalities using track structure theory and general multi-target,multi-hit models makes evident that the targets for radiation-induced effects in physical and bio-logical systems are of comparable size. Availability of bio-equivalent dosimeters would represent amajor progress in radiation protection, radiation biophysics and medical radiation physics, for itwould allow to evaluate the biological effectiveness of radiations of different quality, largely inde-pendently of dose and dose rate. As a consequence, these studies directly support the developmentof new radiation protection concepts and thus concern a broad spectrum of applications rangingfrom environmental physics, medical diagnosis and therapy to human space exploration.

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Review and Cross-comparison of Matroshka PhantomMeasurements in Different Compartments of the

International Space StationChristina Hofstatter1, Michael Hajek1, Thomas Berger2, Pawe l Bilski3, Daniel Matthia2,

Monika Puchalska4, Andrea Zechner1, Gunther Reitz2

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria2German Aerospace Center, Linder Hohe, 51147 Koln, Germany

3The Henryk Niewodniczaski Institute of Nuclear Physics, 152 Radzikowskiego Str., 31-342 Krakow, Poland4Chalmers University of Technology, SE-412 96 Gothenburg, Sweden

Astronauts working and living in space are exposed to considerably higher doses and differentqualities of ionizing radiation than people on ground. Matroshka, a European Space Agency exper-iment under coordination of the German Aerospace Centre, is the most comprehensive effort so farin radiation protection dosimetry in space using an anthropomorphic upper torso phantom knownfrom radiotherapy treatment planning to map the dose distribution throughout a simulated humanbody on board the International Space Station (ISS). Absorbed dose and dose equivalent measuredby nuclear track detectors and miniature thermoluminescence dosimeters embedded in a regulargrid and at the site of vital organs are combined with detailed numerical models to allow for esti-mation of effective dose. Monte Carlo simulations using the transport codes FLUKA and GEANT4that provide calculations of particle fluence and dose for various radiation environment conditionsfurther support the experiment and improve cancer risk projections for future long-term space ex-ploration beyond the Earths magnetosphere. The paper presents a review and cross-comparison ofdata acquired during four missions between January 2004 and March 2011, in which the phantomhas been installed in different compartments of the Russian and Japanese segments of the ISS:outside and inside Zvezda, inside Pirs and inside Kibo.

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Korrelation relativer Feuchte undStromumwandlungskoeffizient der Dunnschicht-Photovoltaik

Maryam Nikbakhti1, Marcus Rennhofer1, Viktor Schlosser1, Karl Berger2, Philipp Weihs3,

Jochen Wagner3, Roman Leidl2, Dietmar Baumgartner4

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria2AIT Austrian Institute of Technology GmbH, Giefinggasse 2, 1210 Vienna, Austria

3University of Natural Resources and Life Sciences, Peter Jordan Strasse 82, 1190 Vienna, Austria4Observatory Kanzelhohe, KFU-Graz, Treffen 9521, Austria

Im Rahmen des nationalen Projektes PV-SPEC wurden an klimatisch und meteorologischunterschiedlichen Standorten verschiedene Modultypen (Mono, CdTe und a-Si) hinsichtlich ihresVerhaltens bezuglich spektraler Anderungen des einfallenden Sonnenlichtes und meteorologischerParameter untersucht. Schlussfolgerungen uber die Umwandlungseffizienz der Module konntengetroffen werden. Dazu wurden Module jeder Type mit 35◦ Neigungswinkel nach Osten, Sudenund Westen an einem Hochgebirgsstandort (1600 m) und einem Flachlandstandort (170 m) ubereinen Zeitraum von 3 Jahren untersucht. Es wurde die Korrelation zwischen den gemessenen Umge-bungsvariablen, der Einstrahlung, den spektralen Bestrahlungsstarkewerten und der Umwand-lungseffizienz η, der Module untersucht. Schwerpunkt der prasentierten Arbeit ist der Einflussder relativen Feuchtigkeit der Luft sowie globale Einstrahlung – E – und spektral aufgelosteEinstrahlung E(λ) auf elektrischen Parameter und Temperatur, Umgebungsbedingungen. Weit-ers wurde die Starke der Alterung der Module innerhalb des Messzeitraumes bestimmt. EineVeranderung der Wetter- oder feuchtebedingten spektralen Anteile der auf ein Modul treffendenEinstrahlung (großteils Rayleigh-Streuung) hin zum “Roten” oder “Blauen” Spektralbereich be-dingt eine unmittelbare Anderung der Umwandlungseffizienz: uber die spektrale Empfindlichkeit(SR) beeinflusst eine solche Anderung den im Modul aus dem Licht generierbaren Strom. Es wur-den die Einflusse der relativen Feuchtigkeit auf Bodenniveau in diesem Zeitraum mit jenen derrelativen Feuchtigkeit des atmospharischen Hohenprofils verglichen. Durch eine Simulation wurdendie theoretischen Maximalwerte der Feuchteabhangigkeit mit den gemessenen Werten verglichen.Die Analyse aller Parameter gibt ein Maß fur die Abhangigkeit der system- und klimarelevantenelektrischen Messgroßen von der relativen Feuchtigkeit der Luft.

POS-47, OGD, Wed, 17:45

AFM investigation of kraft pulp fiber swelling in controlledhumidity

Christian Ganser1, Robert Schennach1, Christian Teichert2

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Montanuniversitat Leoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

Kraft pulp fibers are wood fibers from softwood, typically spruce and pine, which are the mainconstituent for so called kraft paper. Kraft paper is used mainly for packaging applications, wherea high strength is required. In this work, the swelling behavior of spruce kraft pulp fibers is in-vestigated by atomic force microscopy (AFM). To perform this task, the AFM was equipped witha fluid cell and a setup where the relative humidity inside the fluid cell can be controlled. Thesetup enables to select any humidity value between approximately 5% and 80% relative humidity.With this setup, a change in surface morphology of the scanned area could be observed. Fur-thermore, the evolution of the characteristic surface wrinkles of dried pulp fibers with increasinghumidity was quantified in two different ways. One way is to measure the distance between thesurface wrinkles, the other to determine their height. It could be shown that the distance be-tween the wrinkles is increasing, whereas the height is decreasing. This means that the surface isbecoming smoother when the fiber is swelling, which is best observed on a completely wet fiber.Supported by Mondi, Kelheim Fibres and the Christian Doppler Research Society, Vienna, Austria.

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POS-48, OGD, Wed, 17:45

Kinetic Monte Carlo Simulations of Nucleation and ThinFilm Growth of Hexaphenyl on Amorphous Mica

Christoph Gleichweit1, Adolf Winkler1, Levent Tumbek1, Karin Zojer1


Ultra-thin films of para-hexaphenyl on sputter amorphized mica(001) exhibit the surprisingbehavior of forming bimodal island size distributions. Small islands were observed besides biggerones. It is believed that as long as the sample is in ultra-high vacuum, there exists a 2D-gas phasebetween the bigger islands, which vanishes by nucleating a lot of small islands when exposed to air.Probably due to the adsorption of water on the surface the energetics of monomers on the surfacechange and islands form. This behavior is named adsorbate induced subsequent nucleation. UsingKMC simulations this effect was tried to be reproduced with the objective of extracting informa-tion about the critical cluster size and the island size distributions. For this reason an algorithmfor edge hopping that respects also the critical island size was developed. The system initializesby starting with an initial concentration of monomers on the surface. These monomers suddenlystart to diffuse and hence nucleate islands with the specified critical nucleus size and diffusion bar-riers. Particles that are part of stable clusters are not anymore allowed to detach from the islands.The simulation stops as soon as all molecules are incorporated into islands. The resulting islanddensities were compared to the experimental results. It turned out that a critical island size ofi = 7 matches the experiments. Moreover, the island size distributions were compared to the onesobtained from the AFM images and were found to agree qualitatively.

POS-49, OGD, Wed, 17:45

Susceptibility measurements of Ni nanostructures on Cu(110)Michael Hohage1, Mariella Denk1, Richard Denk1, Robert Mittermair1, Daniel Queteschiner1,

Lidong Sun1, Peter Zeppenfeld1

1Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria

A set-up capable of in-situ magnetic susceptibility measurements is introduced. The magneticmeasurements are based on a Reflectance Difference Spectrometer (RDS), by exploiting its highsensitivity to the polar Magneto-Optic Kerr Effect (RD-MOKE). The external magnetic field iscreated by a magnetic coil placed in close vicinity of the sample. For susceptibility measurements asinusoidal magnetic field is applied to the sample. The response of the RD-MOKE signal at photonenergies between 1.5 and 5 eV is frequency analyzed and the amplitudes and phases of the firstand higher harmonics are obtained. The capability of this set-up is demonstrated for ultra thin Nifilms on Cu(110)-(2×1)O. Comparison to regular RD-MOKE shows that the signal-to-noise ratiohas been substantially improved. The analysis of the first and higher harmonics allows studyingmagnetic phase transitions in more detail: The spin reorientation transition (SRT) occurring at aNi coverage of 9 ML on Cu(110)-(2×1)O and the behavior of Ni-films around the Curie temper-ature have been investigated and the ferromagnetic and (quasi-)paramagnetic behavior has beenidentified. In the ferromagnetic regime hysteresis curves have been obtained. The improved signalallows us to investigate the magnetic properties of CoTMPP films on Cu(110)-(2×1)O. At photonenergies of 2.7 eV where a strong optical transition occurs also the susceptibility shows a peak.Thus we can clearly correlate the magnetic susceptibility to the optical transitions of the films.

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POS-50, OGD, Wed, 17:45

Dynamic plowing lithography and 6P thin film growth ongraphene investigated by atomic force microscopy

Markus Kratzer1, Stefan Klima1, Borislav Vasic2, Aleksandar Matkovic2, Andreas Pavitschitz1,Uros Ralevic2, Djordje Jovanovic2, Christian Ganser1, Christian Teichert1, Rados Gajic2

1Montanuniversitat Leoben, Franz-Josef Strasse 18, 8700 Leoben, Austria2Institute of Physics, Pregrevica 118, P. O. Box 68, 11080 Belgrade, Serbia

For the design of novel graphene based devices specific modifications and manipulations ofgraphene are essential. The desired properties might be achieved by selective straining and/ormultistacking of graphene. As a model system we investigated the growth morphology of therodlike para-hexaphenyl (6P) molecule on as prepared and dynamic plowing lithography (DPL)modified graphene. As substrate exfoliated graphene flakes on silicon dioxide (SiO2) were used.The DPL of the graphene was performed by bringing the very hard diamond coated tip of a vibrat-ing atomic force microscopy (AFM) probe into close proximity to the substrate. Depending on thechosen experimental parameters the interaction forces between tip and substrate lead either to alocal deformation or even to cutting of the graphene flake. The 6P was deposited by means of hotwall epitaxy at sample temperatures above room temperature. The resulting film morphologies onthe unaltered and DPL modified graphene were investigated via atomic force microscopy. While onthe SiO2 only 6P islands consisting from upright standing molecules are found there are additionalneedle like structures exclusively found on the graphene.

POS-51, OGD, Wed, 17:45

Morphological investigations of viscose fibers by atomic forcemicroscopy

Patrice Kreiml1, Christian Ganser1, Robert Schennach1, Christian Teichert2

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Montanuniversitat Leoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

Viscose fibers are used in textiles, hygiene products, and medical applications. The fibers arespun from a viscose solution of cellulose. Their cross-section is shaped by spinning the viscose so-lution through a spinneret, thus forming the fibers. The water absorption is an important propertyin the applications mentioned. Here, two samples of viscose fibers were investigated, which showeddifferent behavior under water absorption. The samples were produced under similar conditions andtherefore morphological investigations were of interest. In this study, the morphology of sampleswith high and low water absorption were compared. The surface was investigated by atomic forcemicroscopy (AFM) in tapping mode. A comprehensive roughness analysis, including height-heightcorrelation function (HHCF), showed no significant differences in the roughness parameters. Onthe surface of all samples, trenches could be observed and further investigation of these trencheswas conducted. Depth and length distribution were similar, but the angle distribution, as well astrench density were different. From this result we conclude that the trench alignment and densityare the main differences in morphology between the two fiber types, which might explain theirdifferent water absoprbtion.

Supported by Kelheim Fibres and the Christian Doppler Research Society, Vienna, Austria.

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POS-52, OGD, Wed, 17:45

Growth and structure of WOx nanolayers on bare Cu(110)and Cu(110)(2×1)O surfaces

David Kuhness1, Martin Denk1, Margareta Wagner1, Svetlozar Surnev1, Giovanni Barcaro2,Luca Sementa2, Fabio Negreiros2, Alessandro Fortunelli2, Falko Netzer1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, 56124 Pisa, Italy

Tungsten trioxide (WO3) is deposited through direct thermal evaporation of WO3 powderunder ultra high vacuum (UHV) conditions onto a bare Cu(110) and onto a Cu(110)(2×1) oxidereconstructed crystal surfaces at room temperature. The growth characteristics have been docu-mented with scanning tunnelling microscopy (STM), low energy electron diffraction (LEED) andsynchrotron x-ray photoemission (XPS) systematically through the range of low, i.e. 0.1 monolayer(ML) to high (2.0 ML) coverage of WOx and annealing of the sample to temperatures from roomtemperature to 700◦C. Several phases of WOx structures have been observed and analyzed. Underparticular growth conditions, i.e. 0.6 ML WO3 and a sample temperature of 300◦C a well orderedsingle phase surface with a quasi-square structure could be prepared onto the Cu(110)(2×1)O sur-face. As the unit cell dimensions of this phase are similar to those of the (ac) projected surface ofCuWO4 single crystals a model with a CuWO4 stoichiometry has been proposed and analyzed inDFT calculations.

This work has been supported by the ERC Advanced Grant SEPON. CPU time at the CINECAsupercomputing center via the ISCRA UT-Ox project is gratefully acknowledged.

POS-53, OGD, Wed, 17:45

Adsorption of Xylan onto Bleached Softwood FibersAlbrecht Miletzky1, Petra Wollboldt2, Manuel Punz3, Hansjorg Weber4

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Kompetenzzentrum Holz GmbH, Altenberger Strasse 69, 4040 Linz, Austria

3Zellstoff Forschung, Analytik, Lenzing AG, Werkstrasse 2, 4860 Lenzing, Austria4Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria

Besides cellulose, hemicelluloses or polyoses (e.g. xylan) are the most common polymers inhigher plants and wood. Hardwood contains up to 35% of xylan. Due to chemical pulping – toremove lignin from the wood matrix and to provide fibers for the production of paper – polysac-charides are getting dissolved and degraded in the cooking liquor. This leads in a reduction of thephysical strength properties of the paper. The aim of this work is to redeposit different xylans onthe surface of pulp fibers to improve their mechanical properties. At first, influencing variables suchas pH, temperature, ionic strength, pulp consistency, concentration of xylan in the suspension andthe dwell period during adsorption were investigated. After different trials the pulp was hydrolyzedto its sugar monomers and analyzed with high-pressure liquid chromatography (HPLC) and nuclearmagnetic resonance spectroscopy (1H NMR). The amount of xylan could be enhanced up to 7%points on bleached softwood kraft pulp. The molecular weight of the xylan and the temperatureshowed the most effect of adsorption. The determination of the zeta potential of the fibers and thedifferent xylans will be shown too. The effect of the surface and total charge of the substrate is ofinterest to get more information about the attractive and repulsive forces as well as the mechanismsbetween the fibers and the colloidal dispersed xylan molecules during adsorption. The electricalproperties of the fibers will be analyzed by using kelvin probe force microscopy (KPFM) as well.

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POS-54, OGD, Wed, 17:45

The contact charging of insulators by atomic force microscopyMonika Mirkowska1, Markus Kratzer1, Christian Teichert1, Helmut Flachberger1


Detailed knowledge on the contact charging behaviour of dielectric materials is of great interestfor technological applications like tribocharging separation of mineral additives. As a model sys-tem, we investigated the contact charging between quartz or calcite and high-density polyethylene(HDPE). An attempt was made to measure the electric charging of microsize single particles uponcontact with well-defined surfaces (monocrystallie surfaces of the same materials as well as withHDPE surfaces). For this purpose, the particles were glued to the ending of AFM cantilevers andforce distance (F-d) curves were measured under controlled temperature and humidity conditions.Additional, Kelvin Probe Force Microscopy (KPFM) and Electrostatic Force Microscopy (EFM)measurements were carried out in order to map local electrical changes at the surface.

POS-55, OGD, Wed, 17:45

Anisotropic growth of ultrathin Mn-oxide nanostructures onAg(100)

Thomas Obermuller1, Svetlozar Surnev1, Alessandro Fortunelli2, Wolfram Steurer1, Falko Netzer1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, 56124 Pisa, Italy

Low-dimensional nanostructures of transition metal oxides on well-defined metal surfaces havenovel physical and chemical properties which differ drastically from their bulk counterparts. Dueto their novel properties, these nanostructures have opened up a new field of fundamental researchand they are also of particular interest for a wide variety of potential application in nanotech-nologies, such as in heterogeneous catalysis, electronic devices and corrosion protection. Here wereport the formation of uniaxially ordered Mn-oxide nanostripes with almost macroscopic dimen-sions (> 1000nm) in length on a Ag(100) substrate. The growth of ultra-thin films of manganeseoxide on a Ag(100) single crystal surface has been studied using STM, AFM and LEED tech-niques. Submonolayer coverages of Mn-oxide have been deposited by thermal evaporation undereither UHV conditions or in oxygen atmosphere followed by a post-oxidation step. As a function ofthe chemical potential of oxygen in the post-oxidation step, three different Mn-oxide phases havebeen detected. While oxygen pressures above 1 × 10−6 mbar lead to a randomly distribution ofhexagonally ordered MnOX islands with a triangular shape, a highly anisotropic growth of longand narrow (2×1) stripes forming a network of Mn-oxide islands is observed at oxygen pressuresaround 5 × 10−7 mbar. For lower oxygen pressures, (2×2) multilayered rectangular islands arefound. The physical origin of this anisotropic growth is discussed in a growth model based on theatomic structure of the (2×1) oxide phase.

Work supported by the ERC Advanced Grant SEPON

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POS-56, OGD, Wed, 17:45

Surface Chemistry Chamber for analysis of OxidesJirı Pavelec1, Michael Schmid1, Ulrike Diebold1, Gareth Parkinson1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Wien, Austria

A new UHV chamber for the investigation of oxide surface chemistry (e.g. In2O3, SnO2, Fe3O4,perovskites, TiO2, ZrO2) is described. The combination of a specially designed sample mountdesign and a molecular beam dosing setup solves difficulties associated with performing Tempera-ture Programmed Desorption experiments on bulk oxide samples. Further spectroscopic techniquesavailable on the system include Ultra Violet Photoelectron Spectroscopy, X-ray Photoelectron Spec-troscopy using a monochromatic X-ray source, Low Energy Electron Diffraction, and Ion ScatteringSpectroscopy. Utilization of a liquid helium flow cryostat allows us to follow reactions from 20-1200K, but also allows physisorption of inert gasses such as Kr, a useful probe of surface defects, andalso the basis of the Buffer Layer Assisted Growth (BLAG) technique for the in-situ preparationof monodisperse nanoparticles. An Electro spray Deposition System is used for the deposition ofnon-volatile organic molecules that otherwise cannot be studied in UHV. This surface chemistryinstrument provide an ideal compliment to our existing STM based studies.

POS-57, OGD, Wed, 17:45

Microscopical electrical investigations of grain boundaries inZnO varistor ceramics

Andreas Pavitschitz1, Michael Hofstaetter1, Peter Supancic1, Christian Teichert1


Varistors are nonlinear voltage dependent ceramic resistors used to suppress and limit transientvoltage surges. The most common material for varistors is doped polycristalline ZnO which showshighly non-linear current-voltage characteristics with rapidly decreasing resistance above a specificvoltage. This effect is caused by so called Schottky barriers at the grain boundaries. Therefore,investigation of the electrical properties of the individual grain boundaries is essential for the under-standing of the varistor effect and the improvement of varistor materials. In this study, the electricalproperties of ZnO multilayer varistors (MLV) were investigated on the microscopic scale employingconductive atomic-force microscopy (C-AFM), Kelvin probe force microscopy (KPFM), and KPFMwith biased MLV electrodes (biased KPFM). The electrical properties of individual grain bound-aries were directly measured with a micro-four-point probe measurement setup. Additionally, thecrystallographic orientation of the single grains was determined with electron backscatter diffrac-tion (EBSD). The electronic properties were associated with the crystallographic orientation dataobtained from EBSD. Employing KPFM on a MLV with an applied bias between the electrodesreveals a step-like voltage drop with steps at the grain boundaries. The relative height of thesesteps is not uniform. Also a dependence of the relative step-height on the direction of the appliedbias was observed.

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POS-58, OGD, Wed, 17:45

Structure Solution of Surface Induced Crystal Structures:Selected Examples of Calamitic Conjugated Molecules

Alexander Pichler1, Markus Neuschitzer1, Michael Dohr1, Alfred Neuhold1, Armin Moser1,Gunter Schwabegger2, Helmut Sitter2, Clemens Simbrunner2, Theo Dingemans3, Eric G lowacki2,

Mihai Irimia-Vladu2, Johannes Gierschner4, Yves Geerts5, Michele Sferrazza5, Roland Resel1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria

3Faculty of Aerospace Engineering, Kluyverweg 1, 2629 HS Delft, Netherlands4Madrid Institute for Advanced Studies, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain

5Universite Libre de Bruxelles, Campus de la Plaine, 1050 Bruxelles, Belgium

Organic molecules in thin films show often specific crystal structures which are different fromthe known single crystal structures. Such surface-induced crystal structures are formed due tothe presence of a surface during the crystallisation process. Within this work we present a spe-cific approach to solve surface induced crystal structures. The solution is based in a first step onthe determination of the crystallographic lattice by indexing the observed Bragg peaks of grazingincidence x-ray diffraction measurements. In a second step the molecular packing within the crys-tallographic unit cell is determined by a rigid body refinement of the molecular structure againstthe experimentally obtained intensities of the Bragg peaks. To check the reliability of the ap-proach the already known crystal structure of dioctylbenzothieno-benzothiophene (C8-BTBT) willbe investigated. As a result of the work the surface induced crystal structures of three differentconjugated molecules will be presented: the well-known dye Tyrian Purple (TP) crystallised ona polyethylene surface, the molecule ternaphthalene (NNN) grown on thermally oxidised siliconwafers and phenylene-butoxyphenyl-acrylonitrile (DBDCS) grown on glass surfaces.

POS-59, OGD, Wed, 17:45

Influence of potassium on the nucleation and growth ofpara-hexaphenyl on mica

Bernhard Putsche1, Adolf Winkler1


Semiconducting oligomers, such as para-hexaphenyl (6P), are attractive candidates as activelayer material for organic electronic devices. A model system to investigate the growth param-eters is 6P on mica. Adsorbed on freshly cleaved mica, 6P forms needlelike islands of flat lyingmolecules on top of a wetting layer. Previous investigations have shown that surface modifications,like sputtering, lead to the formation of islands of standing molecules and dewetting. When micais cleaved, the sample always splits along its potassium layer and a half monolayer of potassiumremains on each face. This contribution describes the effects of an increased amount of potassiumon the thin film layer growth of 6P. Performing the measurements in ultra-high vacuum ensuredprecisely controlled conditions for the experiments. 6P was evaporated by using a Knudsen celland the amount of evaporated material was determined by a quartz microbalance. Potassium wasdeposited by using a SAES Getter source. Thermal desorption spectroscopy (TDS, in-situ) andatomic force microscopy (AFM, ex-situ) were the main analytical methods to describe the effectsof potassium on the growth of the 6P molecules. Auger electron spectroscopy (AES) was appliedfor chemical analysis of the mica sample before and after the potassium deposition. It turnedout that pre-adsorbed potassium causes dewetting and the formation of islands of standing 6Pmolecules. AES and TDS measurements revealed that proper potassium adsorption/desorptioncycles are leading to a saturated potassium coverage of one monolayer on mica, which is stable upto 1000K.

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POS-60, OGD, Wed, 17:45

Thin cellulose films as model systems for paper-fibresSebastian Rohm1, Robert Schennach1


Paper fibres mainly consists of long cellulose and hemicellulose molecules. To investigate howthese molecules are attracted to each other thin cellulose-layers are spin-coated on a 2x2cm2 silicon-wafer. Since Cellulose is difficult to solve into a solvent, first Trimetylsilycellulose (solved intoToluol) is spin-coated on the surface which then is transformed to cellulose by hydrolysis. Thisspin-coating process is done 4 times to get a layer-thickness of about 200nm. For swelling thesewafers are laid into distilled water. To measure ionic influences some wafers are also swelled intowater with 0.1mol/l CaCl2. After that two cellulose-surfaces are laid against one another andput into a dryer. There the physical bonds between these surfaces are formed while the waterevaporates. After 4 hours of drying the thin films are joint and z-strength-tests can be performed.For that, the wafers are fixed on the silicon-side and a tensile-test is made. The maximum force,the strain and the energy needed is measured in this experiment. The advantage of this methodis, that only physical bonds like van der Waals-, Ionic- and Hydrogenbonds are contributing. Inaddition, the films are investigated with an Atomic-Force-Microscope, before and after the strength-tests, to find out where the molecules form bonds with each other. To measure the influence ofhemicellulose-molecules, xylan-layers are spin-coated on the cellulose-layer and the same measure-ments are performed.

POS-61, OGD, Wed, 17:45

Initial growth of Rubicene on Silicon OxideBoris Scherwitzl1, Adolf Winkler1, Walter Lukesch1


In the course of the last decades organic microelectronic devices became of increasing impor-tance. The use of organic or hybrid organic devices yields advantages in a variety of fields ofapplication. Flexible displays or solar cells are already notable examples of present day technol-ogy. Inventing new and improving existing devices requires full understanding and best controlof building processes. Therefore studies of the initial stages of organic thin film growth are es-sential. This contribution describes the behavior of rubicene film growth on silicon oxide withrespect to sample treatments. Physical vapor deposition was the method of choice for creatingfilms from sub-monolayers up to multilayers. Rubicene was evaporated by using a Knudsen celland the amount of evaporated material was determined by a quartz micro balance. Auger Elec-tron Spectroscopy (AES) was applied for chemical analysis and proved homogeneity of the sample.Thermal Desorption Spectroscopy (TDS) was the main analytical method along with Atomic ForceMicroscopy (AFM) to determine the behavior of the molecules on the substrate. The surface wasintentionally altered by argon sputtering and carbon deposition. Performing the measurements inultra-high vacuum (UHV) ensured precisely controlled conditions for the experiments, although theAFM measurements were subsequently done ex-situ. It could be shown that the rubicene forma-tion, especially the thermal stability and dewetting, depends strongly on the substrate conditions.Furthermore, it could be demonstrated by AES and TDS that on a clean silica substrate the firstmonolayer of rubicene dissociates upon heating the surface.

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POS-62, OGD, Wed, 17:45

Bismuth surface phonon modes from helium atom scatteringexperiments

Anton Tamtogl1, Michael Mayrhofer-Reinhartshuber1, Patrick Kraus1, Davide Campi2,

Giorgio Benedek2, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2Universita degli Studi di Milano-Bicocca, Via Roberto Cozzi 53, 20125 Milano, Italy

The semimetal bismuth (Bi) is a prime candidate for the study of quantum size effects insolids[1]. Only recently anisotropies in conductivity measurements of Bi have been observed[2].Whereas Bi bulk properties have been analyzed very well open questions concerning the latticedynamics of the Bi surfaces remain[1]. Helium Atom Scattering (HAS) allows the investigation ofelastic as well as inelastic phenomena associated with the shape and changes of the electron den-sity corrugation at the Bi(111) surface[3]. Therefore, using inelastic HAS measurements the surfacephonon dispersion of Bi(111) could be determined for the first time. In both high-symmetry di-rections the phonon dispersion exhibits a Rayleigh mode, a strong longitudinal resonance and anearly dispersionless branch at approximately 4 meV. A comparison of the phonon dispersion withcalculations from density functional perturbation theory show that the longitudinal resonance ex-hibits the largest amplitude in the second layer and the flat phonon branch originates even froman atomic displacement in the third layer. The observation of this subsurface modes in heliumscattering is only possible due to the electron phonon-coupling. Thereby oscillations of the electroncharge density above the first layer are caused by the movement of the atoms in subsurface layers.

[1] P. Hofmann, Prog. Surf. Sci. 81 (2006) 191.[2] S. A. Parameswaran et al., Nat. Phys. 8 (2012) 7[3] M. Mayrhofer-Reinhartshuber et al., J. Phys.: Cond. Matt. 24 (2012) 104008

POS-63, OGD, Wed, 17:45

Attachment limited versus diffusion limited nucleation oforganic molecules: Hexaphenyl on sputter-modified mica

Levent Tumbek1, Adolf Winkler1


The nucleation and growth of point-like particles, like metal atoms, is usually discussed in theframework of diffusion limited aggregation (DLA). In this contribution we demonstrate that forextended particles, like for the rod-like organic molecules hexaphenyl (6P), this nucleation scenariodoes not always hold. The reason is that the condition of an incorporation probability of unityis not fulfilled any longer for these monomers. A special characteristics of DLA is that the islanddensity N scales with N = c(R/D)(i/(i+2)), with R: deposition rate, D: diffusion rate, and i: crit-ical island size. For this scenario the critical island size i, which can be easily obtained from theslope in the plot lnN vs lnR, should vary between 0.33 and 1. However, for the island growthof 6P on especially sputter-amorphized mica we obtain a slope of 1.4. Indeed, this result can beexplained by assuming that the nucleation is governed by attachment limited aggregation (ALA).In this case the island density N scales with N = c(R/D)(2i/(i+3)), and i can vary between 0.5and 2. Consequently, a critical island size of 7 is obtained in this case. The crucial parameter forthe growth mode is the roughness of the substrate surface, as induced by ion sputtering. Withincreasing surface roughness the diffusion probability of the molecules decreases and the growthmode changes from ALA to DLA.

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POS-64, OGD, Wed, 17:45

Displacement and Replacement in Organic HeterostructuresThomas Ules1, Eva Reinisch1, Markus Ostler2, Michael Ramsey1, Georg Koller1

1University of Graz, Universitatsplatz 5, 8010 Graz, Austria2University Erlangen Nurnberg, Erwin-Rommel-Strasse 1, 91058 Erlangen, Germany

In this LEED/Angle Resolved UPS study an heterostructure system is presented which shows acounter intuitive reversible replacement of two different organic molecules at the molecule substrateinterface. The organic rod like molecule sexiphenyl (6P) forms a well ordered monolayer on Ag(110)which is clearly characterised by its valence band emissions and its geometric structure. Valenceband tomography of the π orbitals show no evidence of backdonation to the 6P LUMO and that6P is in its twisted confirmation with its long molecular axes aligned perpendicular to the substrateatomic rows. Upon the deposition of pentacene (5A) on it, a density of states appears at the Fermiedge. Fermi surface maps identify this intensity as the ex-LUMO of 5A filled via backdonationfrom the substrate. This, together with the fact that 6P emissions are still dominant, suggeststhat 5A has gone to the interface. Extraordinarily, on ramping the temperature the 6P featuresfirst disappear and then reappear at the temperature of desorption of the 5A/Ag(110) monolayer.This de/re-wetting is also observed with LEED where de-wetting of 6P results in the appearanceof a well ordered 5A monolayer LEED pattern which, at the 5A desorption temperature, changescompletely to the 6P monolayer pattern. That the chemisorbed 5A desorbs before the physisorbed6P is apparently counterintuitive and will be discussed in terms of the energetics of de-wetting (3Disland formation) and wetting monolayers.

Acknowledement: This work is supported by the Austrian Science Foundation FWF.

POS-65, OGD, Wed, 17:45

Reversible transitions between surface reconstructions onSrTiO3

Zhiming Wang1, Stefan Gerhold1, Michael Schmid1, Ulrike Diebold1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Wien, Austria

SrTiO3 as an archetypical perovskite oxide has attracted intense interest in diverse fields rang-ing from fundamental solid-state physics to photocatalysis chemistry, material science, as well aselectronics applications. Related research has become even more exciting since the recent discov-ery of a 2DEG at the SrTiO3 surface and interfaces. In all these applications the structural andelectronic surface properties are of vital importance, yet perovskite surfaces are notoriously com-plex and hard to control. Here we report investigations on SrTiO3 surfaces using STM, LEED andXPS. Atomically well-defined SrTiO3 (110) surfaces can be obtained by Ar+ sputtering followed byannealing. Mono-phased reconstructions are obtained, and the evolution between different phasescan be tuned reversibly by depositing Sr or Ti. The tuning mechanisms are revealed as a chemicalconcentration-driven process on the surface.

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POS-66, OGD, Wed, 17:45

Investigation of the surface charge of Viscose Fibres by XPSand ATR

Frederik Weber1, Robert Schennach1, Rene Eckhart1, Georg Koller2, Ingo Bernt3

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria2University of Graz, Universitatsplatz 5, 8010 Graz, Austria

3Kelheim Fibres GmbH, Regensburger Strasse 109, 93309 Kelheim, Germany

The primary objective within the CD-Laboratory is to get a better understanding of the mech-anism how paper fibres stick together. There are five types of interactions that determine thespecific joint strength in the contact zone between the fibres: mechanical interlocking, interdifu-sion, induced dipoles, van der waals forces and hydrogen bonds. Regenerated cellulose fibres likeviscose fibres are in principle chemically identical to wood pulp fibers. They are available withwell defined parameters like cross section, fibre length or fibre width and in contrast to wood pulpfibres, are rather smooth, without fibrils on the surface. Therefore, they are model-fibres whichare perfect for investigating the mechanism of fibre-fibre bonds and to get a better understandinghow paper fibres stick together and perform in a paper sheet. A big advantage of viscose fibres isthe feasibility to mix several additives to them. Thereby defined anionic as well as cationic fibrescan be achieved. Without mechanical interlocking, viscose fibres can be used to investigate theinfluence of surface charges on the bond strength. Four kinds of fibres were investigated by X-rayphotoelectronspectroscopy (XPS) and attenuated total reflection spectroscopy (ATR). The investi-gated fibres only differ in charge but have the same cross section and dimensions. Two anionic anda cationic fibre were investigated using the regular viscose fibre as a reference. Via XPS and ATRthe amount of anionic and of the cationic additives were investigate to get an idea of the chargedensity of all used fibres.

POS-67, OGD, Wed, 17:45

Selective Photo-induced Cross-linking of Polynorbornens:Towards the Fabrication of Polymer 2D- and 3D-

MicrostructuresArchim Wolfberger1, Thomas Griesser1, Ute Daschiel1,2, Volker Schmidt3, Abdellatif Jerrar4,

Christian Teichert4, Wolfgang Kern1

1University of Leoben, Otto-Glockel-Strasse 2, 8700 Leoben, Austria2Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria

3Joanneum Research GmbH Weiz, Franz-Pichler-Strasse 30, 8160 Weiz, Austria4Montanuniversitat Leoben, Franz Josef Strasse 18, 8700 Leoben, Austria

Ring opening metathesis polymerization (ROMP) has become an important tool for the syn-thesis of highly defined polymers and various polymer architectures. In the present work, theresidual double bonds in ROMP derived polymeric materials were exploited for a photoinducedthiol-ene reaction in order to achieve a selective cross-linking of the macromolecules. To demon-strate the versatility of this reaction for the realization of polymeric microstructures, thin films ofpoly(norbornene dicarboxylic acid, dimethylester) were structured by means of photolithography.Besides the photoinduced thiol-ene reaction, which was investigated by means of FTIR measure-ments, also the cross-linking of the macromolecules and thus the change in the solubility wereassessed by means of sol-gel analysis. Thin films of this polymer were laterally patterned usingconventional single photon lithography leading to resolutions in the µm range. Going a step further,this approach can also be used for realizing 3D polynorborne microstructures employing the twophoto absorption writing technique. The obtained 3D features have been visualized by scanningelectron microscopy and atomic force microscopy, respectively. The accessibility and reactivityof the polynorbornene main chain C = C double bonds in the thiol-ene reaction paves the waytowards novel strategies for the realization of polymer 2D and 3D microstructures.

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POS-68, PMP, Wed, 17:45

Raman investigation of tannin foamsMaurizio Musso1, Alexander Petutschnigg2, Gianluca Tondi2

1University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria2FHS, University of Applied Sciences, Urstein Sud 1, 5412 Puch/Salzburg, Austria

Tannin-based organic foams are new foam materials which are environmentally friendly, resis-tant to fire and inexpensive, and intended to be used for building insulation, and also as waterabsorber or shock absorber. These foams can be produced via an acid catalyzed polycondensationreaction between condensed flavonoids and furfuryl alcohol [1-2]. Several studies deal with themechanism involved in this process [3], but some ambiguities still persist. Raman spectroscopyis an analytical technique suitable for the non-destructive chemical investigation of polymers, al-lowing to determine the presence of functional groups within a polymer through the interaction oflaser light with the vibrational modes of the molecules setting up the sample under investigation[4]. By this spectroscopic technique we have characterized the tannin-based foams and comparedtheir spectral signature with that of tannins, and of polymerized furfuryl alcohol [5]. Similaritiesand differences to the spectral features of carbonaceous material are discussed.

[1] Tondi G., Zhao W., Pizzi A., Du G., Fierro V., Celzard A., Bioresources Technology 100, 5162(2009)[2] Tondi G., Fierro V., Pizzi A., Celzard A., Carbon 47, 1480 (2009)[3] Gandini A., Polym. Chem. 1, 245 (2010)[4] M.A. Amer, Raman Spectroscopy for Soft Matter Applications, Wiley, Hoboken (2009)[5] S. Bertarione, F. Bonino, F. Cesano, S. Jain, M. Zanetti, D. Scarano, and A. Zecchina, J. Phys.Chem. B 113, 10571 (2009)

POS-69, PMP, Wed, 17:45

The effect of sacrificial bonds on the mechanical behavior of asingle polymer chain- A Monte Carlo study

Soran Nabavi1, Markus Hartmann1

1Montanuniversitat Leoben, Franz Josef Strasse 18, 8700 Leoben, Austria

Understanding the basic building principles of biological materials from a fundamental point ofview is a necessary prerequisite for possible transfer of these principles to technology. The byssalthread is an especially fascinating material showing high toughness, stiffness and extensibility. Thebyssal thread is secreted by marine mussels to adhere to rocky substrates. Being covered witha hard coating providing wear resistance, it shows an extensibility of more than 100 % with theability of self-healing. Experimental studies on this system suggest that the high extensibility isdue to so called “sacrificial bonds” (SBs). Sacrificial Bonds are weaker than the covalent bondsholding the structure together and they can thermally induced open and close reversibly. The SBsbreak before the covalent bond rupture, providing hidden length and allowing for efficient energydissipation. By this effect the toughness of the structure is significantly enhanced. These findingsmotivate the following simple model. The basic unit is a linear, covalently bonded polymer chain.Some of the monomers (so called sticky sites) can additionally form sacificial bonds. Starting froma collapsed chain cyclic loading experiments were mimicked by determination of load-displacementcurves by calculation of the mean force exerted by the chain for several end-to-end distances. Theeffect of the density and of the arrangement (ordered, random) of sticky sites on the mechanicalbehavior of the chain was investigated. For sufficiently high sticky site densities a pronouncedhysteresis between stretching and relaxing of the chain could be observed.

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ContributorsAAbele, Hartmut, 148–150, 152Abermann, Stephan, 121Adam, Wolfgang, 21, 43Ahn, Sang Il, 93Aichmayer, Barbara, 157Akbarzadeh, Johanna, 121, 154Akhtar, Nadeem, 144Akis, Richard, 86Alberti, Carlos Armando, 165Alexewicz, Alexander, 95Alkofer, Reinhard, 46, 48, 49Al-Saidi, Wissam, 120Amann, Peter, 118Amenitsch, Heinz, 87, 97, 99An der Lan, Lukas, 146Andersson, Pontus, 151Andrews, Aaron Maxwell, 92, 95, 160Anjum, Naveed, 144Aoki, Nobuyuki, 86Argentero, Giacomo, 127Arndt, Markus, 76Arrigoni, Enrico, 91ASACUSA Collaboration, The, 40Atkinson, Paola, 86Ausserlechner, Simon, 96Aziz, Kirmanj, 161

BBadurek, Gerald, 52Balakireva, Irina, 151Balazs, Peter, 67, 68Baranov, Mikhail, 118Barcaro, Giovanni, 124, 170Bartl, Peter, 146Bauer, Gunther, 155Baumgartner, Dietmar, 167Baumgartner, Oskar, 92Baumgartner, Robert, 69Belushkin, Maxim, 95Benedek, Giorgio, 175Bergauer, Thomas, 56, 57Berger, Karl, 167Berger, Thomas, 111, 166Bergmann, Olaf, 42Berkebile, Stephen, 129, 130Bernet, Stefan, 19Bernt, Ingo, 177Berrada, Tarik, 76Bertel, Erminald, 118Besser, Bruno, 106Betz, Thomas, 75Bilski, Pawe l, 166

Blaha, Peter, 157Blatnik, Matthias, 49Brandner, Hannes, 96Brandstatter, Birgit, 144Briegel, Hans, 21Brueckl, Hubert, 121Brunner, Frank, 95Brunner, Roland, 86, 93Brunner, Stefan, 59, 148Buchriegler, Josef, 42, 51, 153Bucker, Robert, 76Bucko, Tomas, 120Bulla, Lukas, 94Burgstaller, Lukas, 93Burke, Adam, 86

CCacho-Nerin, Fernando, 87, 97, 99Campi, Davide, 175Capriotti, Mattia, 95Cargnelli, Michael, 40Carilli, Jessica, 112Cervinka, Thomas, 152Charles, William, 93Chioncel, Liviu, 91Choi, Joongil Jake, 126Chrastina, Daniel, 154Colavita, Paula, 121Cordin, Michael, 118Costacurta, Stefano, 87Cronenberg, Gunther, 148Cronin, James, 17Curceanu, Catalina, 59

DDaghofer, Maria, 100, 101Daschiel, Ute, 177Daxner, Mathias, 146Della Valle, Raphaele, 125Denifl, Stephan, 79, 81, 146Denk, Mariella, 168Denk, Martin, 124, 170Denk, Richard, 168Detz, Hermann, 92, 160Diaz, Ana, 154Diebold, Ulrike, 118, 126, 127, 172, 176Diehl, Sebastian, 118Diermaier, Martin, 40, 41Dimopoulos, Theodorus, 121Dingemans, Theo, 173Ditlbacher, Harald, 77Djuric, Tatjana, 130Doblhoff-Dier, Nicolette, 20

179

Dohr, Michael, 96, 173Doljeschi, Paul, 56, 57Draxl, Claudia, 119Duehrssen-Debling, Michael, 54

EEcht, Olof, 146Eck, Hans, 163Eckhart, Rene, 177Egger, David, 120Eichmann, Gernot, 50Einkemmer, Lukas, 160Ellis, Andrew, 146Ellmeier, Michaela, 145Erhart, Jacqueline, 149, 150, 152Ernst, Wolfgang, 75, 78, 80, 81, 123, 175Ertler, Christian, 90, 91Eschlbock-Fuchs, Simon, 145Etzelstorfer, Tanja, 88, 154, 155

FFaccinelli, Martin, 156Falcaro, Paolo, 87Fattinger, Michael, 131Faustini, Marco, 87Fecht, Hans-Jorg, 98Federmann, Silke, 40Feige, Jenny, 41, 42Ferry, David, 86Fifield, Keith, 41Fillunger, Harald, 149Filter, Hanno, 148Fischer, Christian, 46Fischer, Franz, 100Fischer, Julia, 54Fisslthaler, Evelin, 123Flachberger, Helmut, 171Flaig, Sylvia, 154Fobes, David, 118Foffi, Giuseppe, 95Folk, Reinhard, 106Forchel, Alfred, 160Forro, Laszlo, 95Forstner, Oliver, 51, 151Fortunelli, Alessandro, 124, 170, 171Franchini, Cesare, 118Frank, Matthias, 65, 66Frank, Sebastian, 58Frankenberger, Annekathrin, 56, 57Franosch, Thomas, 95Friedl, Markus, 56, 57Frisen, Jonas, 42Fritz-Popovski, Gerhard, 87, 157Fromherz, Thomas, 93Fruhwirth, Edwin, 55Fruhwirth, Rudolf, 57, 58

Fuchsbichler, Bernd, 98

GGajic, Rados, 169Gall, Johannes, 129Gammer, Christoph, 97Gamper, Bettina, 82Gansch, Roman, 92Ganser, Christian, 167, 169Garay Walls, Francisca, 54Geerts, Yves, 96, 125, 173Geist, David, 97Gerhold, Stefan, 176Gerstmann, Johann, 30Gfall, Immanuel, 56, 57Gießibl, Franz, 18Gierschner, Johannes, 173Giordani, Silvia, 121Glattauer, Robin, 58Gleichweit, Christoph, 130, 168Glushko, Oleksandr, 93Gmachl, Claire, 93Gocke, Tobias, 46Golob, Andreas, 105Golser, Robin, 41, 42, 51, 151, 153Gosselsberger, Christoph, 52Gottfried, Strasser, 93Goulart, Marcelo, 79, 146G lowacki, Eric, 173Graber, Gerhard, 71Granitzer, Petra, 155Griesser, Thomas, 177Grimm, Matthias, 95Grobosch, Mandy, 124Grogger, Werner, 123Groiss, Heiko, 155Grosso, David, 87Gruber, Christian, 77Gruber, Lukas, 59, 148Gruber, Thomas, 75Gschliesser, David, 79, 146Guedes Matias, Carolina, 146Gusenleitner, Sina, 130Gutberlet, Thomas, 113

HHadley, Peter, 156Haiden, Philip, 149Hajek, Michael, 111, 165, 166HAK/HAS, Mistelbach, 31Hammer, Rene, 91Hanstorp, Dag, 151Harrington Jr, Robert Duane, 54Hartmann, Markus, 100, 178Hasewend, Matthias, 80Haslinger, Michael, 145

180

Hauser, Andreas, 75, 81Hebenstreit, Florian, 46Heiss, Wolfgang, 87, 88Heitz, Johannes, 145Herbst, Tina K., 47Hieckel, Marcel, 118Hinterreiter, Andreas, 145Hirschl, Robin, 29Hirschmugl-Gaisch, Sabine, 163Hirtl, Albert, 148Hlawacek, Gregor, 123Hofer, Ferdinand, 77Hofling, Sven, 160Hofstaetter, Michael, 172Hofstatter, Christina, 111, 166Hohage, Michael, 129, 168Hohenau, Andreas, 77, 80Hohenester, Ulrich, 77Hohl, Roland, 111Holdrich, Robert, 65Holec, David, 100Holy, Vaclav, 88, 155Hopfer, Markus, 49Horselmann, Ingo, 124Horvath, Miklos, 149Hrauda, Nina, 155Huber, Harald, 152Huber, Markus, 47, 48Huber, Norbert, 145Huesing, Nicola, 154Huhnermann, Harry, 144Humer, Markus, 93

IInnocenzi, Plinio, 87Irimia-Vladu, Mihai, 173Irmler, Christian, 56, 57Isella, Giovanni, 154Isepp, Katharina, 150Ishiwatari, Tomoichi, 40

JJanits, Beatrix, 164Jankovec, Martin, 148Jaques, Vincent, 154Jeney, Sylvia, 95Jenke, Tobias, 39, 148Jericha, Erwin, 52Jerrar, Abdellatif, 177Jesacher, Alexander, 19Jestin, Jacques, 113Jovanovic, Djordje, 169Jungnikl, Karin, 99Jussel, Patrick, 44

KKahn, Saranjam, 19

Kalchmair, Stefan, 92Kalliokoski, M., 162Kaltenbrunner, Martin, 90Kamencek, Thomas, 61Karnthaler, Peter, 97Kaseß, Christian, 70Kautsch, Andreas, 80Kazakov, Georgy, 147Keplinger, Mario, 88Kern, Wolfgang, 177Kerscher, Tobias, 156Khinast, Johannes, 111Kiener, Daniel, 19Kirchengast, Gottfried, 162Kirchner, Helmut, 158Kirnstotter, Stefan, 156Klima, Stefan, 169Klopf, Michael, 150Kneringer, Emmerich, 45Knoll, Peter, 148, 157, 161Knupfer, Martin, 124Koch, Markus, 78, 80, 81, 123Koch, Reinhold, 131Kohlfurst, Christian, 46Kolıbal, Miroslav, 127Koller, Georg, 125, 129, 176, 177Koller, Stefan, 98Kolmhofer, Philipp, 145Kondratenko, Sergey, 126Konrad, Gertrud, 52, 149, 150, 152Korner, Christine, 111Korschinek, Gunther, 41Kosina, Hans, 92Kourtis, Stefanos, 100Kovac, Pavol, 94Kovalenko, Maksym, 88Kozyrev, Yury, 126Kraft, Jochen, 134Kramer, Sebastian, 146Kraml, Armand, 107Kraml, Sabine, 58Kranzelbinder, Heinrich, 162Kratschmer, Ilse, 44Kratzer, Markus, 126, 169, 171Kraus, Patrick, 175Krause, Reinhard, 162Kreiml, Patrice, 169Krenn, Heinz, 94, 108Krenn, Joachim, 77, 80Krenn, Kurt, 157Kreuzer, Wolfgang, 69–71Kriegner, Dominik, 88Krois, Gunter, 78Kronland-Martinet, Richard, 68Kuetgens, Ulrich, 152Kufstein, Stadttheater, 22

181

Kuhness, David, 124, 170Kumar, Sanjeev, 101Kusar, Primoz, 77Kutschera, Walter, 42

LLaback, Bernhard, 68–70Lackner, Florian, 78Laggner, Peter, 99Lammegger, Roland, 145LEANNIS network, The, 39Lechner, Rainer, 87Leidl, Roman, 167Leidlmair, Christian, 146Leising, Gunther, 30Leitner, Martin, 156, 162Leitner, Matthias, 159Lettenbichler, Jakob, 57Li, Chenghao, 160Liebl, Jakob, 42Lindahl, Anton, 151Loffler, Andreas, 160Lonez, Caroline, 113Lorbek, Stefan, 96Lucha, Wolfgang, 151Luckabauer, Martin, 98Luftner, Daniel, 125Lukas, Wolfgang, 45Lukesch, Walter, 174Lutzer, Bernhard, 54

MMaaß, Sebastian, 152Maas, Axel, 47Mader, Valentin, 48Magnes, Werner, 145Mahmoudi, Nazila, 58Mai, Patrick, 160Mair, Klaus, 42, 51Majdak, Piotr, 69, 70Malbrunot, Chloe, 40Malfatti, Luca, 87Mandl, Bernhard, 88Mao, Zhiqiang, 118Marmiroli, Benedetta, 87, 97, 99Marton, Johann, 39, 40, 59, 148Martschini, Martin, 42, 51, 151Massiczek, Oswald, 40, 41Matias, Carolina, 79Matkovic, Aleksandar, 169Matthia, Daniel, 166Mauracher, Andreas, 146Mayrhofer, Paul, 100Mayrhofer-Reinhartshuber, Michael, 175Mazuheli, Stefan, 61Meisels, Ronald, 86, 93

Melikhov, Dimitri, 151Melisek, Tibor, 94Mendoza, Benjamin Levy, 165Menezes, Jose, 111Menzel, Alexander, 118Merchel, Silke, 41Mercurio, Giuseppe, 20Messing, Maria, 88Meunier, Sabine, 68Michlmayer, Leonard, 42Mihocic, Michael, 70Miletzky, Albrecht, 170Milko, Matus, 119Mirkowska, Monika, 171Mitaroff, Winfried, 58Mittendorfer, Florian, 118, 128Mitter, Mario, 48, 49Mittermair, Robert, 168Mor, Flavio, 95Morak, Roland Johann, 157Morales, Puerto, 155Moser, Armin, 125, 173Moser, Martin, 152Muccioli, Luca, 162Mulleder, Thomas, 61Mullegger, Stefan, 131Muller, Mario, 61Muller, Stefan, 156Murer, Gerhard, 135Musso, Maurizio, 157, 161, 178

NNabavi, Soran, 178Nadler, Moritz, 57Necciari, Thibaud, 68Negreiros, Fabio, 124, 170Netzer, Falko, 124, 130, 170, 171Neuhold, Alfred, 96, 173Neuschitzer, Markus, 96, 173Niedermayr, Michael, 147Nikbakhti, Maryam, 167Novotny, Zbynek, 127

OOberauer, Christoph, 161Obermuller, Thomas, 171Ochiai, Yuichi, 86Ostermann, Laurin, 78Ostler, Markus, 129, 176Oswald, Josef, 158

PPaasch, Gernot, 124Pabisch, Silvia, 158, 160Pabst, Georg, 113Pacheco, Manuel, 159

182

Paris, Oskar, 87, 100, 157, 160Parkinson, Gareth, 127, 172Parlar, Anil, 95Parth, Dieter, 31Parz, Peter, 98, 159Pavelec, Jirı, 172Pavitschitz, Andreas, 169, 172Pawlowski, Jan Martin, 47Pedarnig, Johannes, 145Peic, Antun, 121PERC Collaboration, The, 52Perez, Javier, 97Perova, Tatiana, 121Peterlik, Herwig, 121, 154, 158, 160Petutschnigg, Alexander, 178Pichler, Alexander, 173Pichler, Franz, 108Pillmayr, Norbert, 28, 33Pirro, David, 65Plagg, Stefan, 71Pobitzer, Martin, 71Podloucky, Raimund, 118, 128, 156Poelsema, Bene, 123Pogany, Dionyz, 95Pohl, Wilfried, 32Pollinger, Andreas, 145Polt, Peter, 122, 155Portolan, Stefano, 160Posch, Thomas, 29Postler, Johannes, 79, 146Potocar, Thomas, 152Pototschnig, Johann, 81Pottlacher, Gernot, 161Potz, Walter, 89–91Prehal, Christian, 126Priller, Alfred, 42, 51, 153Probst, Michael, 146Prugger, B., 162Puchalska, Monika, 166Puchegger, Stephan, 158, 160Puff, Werner, 98, 159Punz, Manuel, 170Puschnig, Peter, 119, 125, 129Puschnigg, Benjamin, 81, 146Putsche, Bernhard, 173

QQueteschiner, Daniel, 129, 168

RRadinger, Gregor, 32Radulescu, Aurel, 113Rahbaran, Babak, 153Rajagopalan, Shibi, 58Ralevic, Uros, 169Rammerstorfer, Franz, 100

Ramsey, Michael, 125, 129, 130, 176Rappolt, Michael, 99Rashidi, Mohammad, 131Rastelli, Armando, 86Ratschek, Martin, 80, 81Rechberger, Veronika, 163Redinger, Josef, 118, 128Reichel, Erich, 163Reingruber, Herbert, 122Reininger, Peter, 92Reinisch, Eva, 129, 176Reissner, Michael, 94, 155Reitberger, Klaus, 22Reiter, Wolfgang, 104Reitz, Gunther, 111, 166Rennhofer, Harald, 160Rennhofer, Marcus, 121, 167Rentenberger, Christian, 97Resel, Roland, 96, 125, 130, 173Ritsch, Elmar, 54Ritsch, Helmut, 78, 146Ritsch-Marte, Monika, 19Rohlen, Johan, 151Rohm, Sebastian, 174Roider, Clemens, 19Romero Vidal, Antonio, 59Roscioni, Otello, 162Rossler, Roman, 145Rubezhanska, Maria, 126Rudamas, Carlos, 159, 165Rugel, Georg, 41Ruiz, Victor, 120Rumpf, Klemens, 155Ruysschaert, Jean-Marie, 113

SSacher, Stefan, 111Sachslehner, Franz, 104Salzburger, Andreas, 45, 54Salzmann, Ingo, 96, 125Sanchis-Alepuz, Helios, 49Sandoghdar, Vahid, 24Sartori, Barbara, 87, 97, 99Sassermann, Mathias, 160Sauerzopf, Clemens, 40Savel, Sophie, 68Schaefer, Bernd-Jochen, 47, 49Schaelicke, Andreas, 54Schaff, Jean-Francois, 76Schaffer, Mathias, 33Schafler, Erhard, 121Scheibelhofer, Otto, 111Scheier, Paul, 79, 81, 146Scheinert, Susanne, 124Schennach, Robert, 119, 121, 167, 169, 174, 177Scherwitzl, Boris, 174

183

Schiefler, Gustav, 154Schittelkopf, Eduard, 163Schlosser, Viktor, 167Schmalzer, Nadine, 61Schmid, Michael, 118, 126, 127, 172, 176Schmidt, Edith, 42Schmidt, Franz, 77Schmidt, Gunther, 157Schmidt, Oliver, 86Schmidt, Volker, 177Schmied, Franz, 121Schmiedmayer, Jorg, 76Schmitz, David, 75Schmon, Alexander, 161Schneider, Christian, 160Schnell, Melanie, 75Schobel, Harald, 146Schofbeck, Robert, 43Schreitl, Matthias, 147Schrenk, Werner, 92, 93Schumm, Thorsten, 76, 147Schustereder, Werner, 156Schwabegger, Gunter, 173Schwanda, Christoph, 45Schwarz, Benedikt, 92Schwarz, Karlheinz, 157Schwarz, Stefan, 149Schwarzer, Clemens, 93Sclafani, Michele, 76Scordo, Alessandro, 59Sementa, Luca, 124, 170Sereni, Paolo, 157, 161Seyller, Thomas, 129Sferrazza, Michele, 96, 125, 173Shen, Quan, 96Sherwood, Peter, 54Shubert, Alvin, 75Shyjumon, Ibrahimkutty, 99SIDDHARTA Collaboration, The, 39Siddiqui, Imran, 82Siegel, Stefan, 160Siess, Josef, 135Sigg, Hans-Christian, 154Sikola, Tomas, 127Simbrunner, Clemens, 173Sitter, Helmut, 173Smiljic, Dusko, 56, 57Sontacchi, Alois, 65Sorta, Stefan, 94Spalding, Kirsty, 42Spolenak, Ralph, 154Sprengel, Wolfgang, 98, 159Stangl, Julian, 88, 154, 155Stanohevic, Zlatan, 92Steier, Peter, 42, 51, 112, 153Steinacker, Harold, 50

Steinhauser, Georg, 147Steinmuller-Nethl, Doris, 134Sterba, Johannes, 51Steurer, Wolfram, 171Stickler, Benjamin, 91Stoger, Bernhard, 118Stolterfoht, Martin, 162Strasser, Gottfried, 92, 95, 160Stricker, Stefan, 46Stuetz, Engelbert, 164Suess, Martin, 154Sun, Lidong, 129, 168Supancic, Peter, 172Surnev, Svetlozar, 124, 170, 171Suzuki, Ken, 59, 148Swain, John, 17Sytnyk, Mykhailo, 88

TTamtogl, Anton, 175Tanzer, Katrin, 81Teichert, Christian, 96, 126, 167, 169, 171, 172,

177Teischinger, Florian, 53Thalhammer, Gregor, 19Thorhallsdottir, Ester, 162Thorne, Felicitas, 45Tinguley, Jean-Claude, 80Tkatchenko, Alexandre, 120Todt, Melanie, 100Tondi, Gianluca, 178Topolovec, Stefan, 94Treberer-Treberspurg, Wolfgang, 56Tributsch, Helmut, 28Tritthart, Stefanie Anna, 164Trotta, Rinaldo, 86Tschurtz, Sabine, 162Tumbek, Levent, 130, 168, 175

UUles, Thomas, 125, 129, 176Usanova, Anna, 44, 54

VValentan, Manfred, 56, 57Vandenbranden, Michel, 113van den Brink, Jeroen, 100, 101Van Frank, Sandrine, 76van Gastel, Raoul, 123Van Opdenbosch, Daniel, 157Vasic, Borislav, 169Vazquez Doce, Oton, 59Veligura, Vasilisa, 123Venderbos, Jorn, 100, 101Vieider, Manuel, 162Vizcaino, Violaine, 81, 146

184

Volgger, Stefan, 161Volk, Alexander, 123von Smekal, Lorenz, 47Voros, Zoltan, 160

WWagner, Jochen, 167Wagner, Margareta, 124, 130, 170Wagner, Thorsten, 129Wallner, Anton, 41, 42Waltenberger, Wolfgang, 43Wang, Xiangzun, 53, 149, 152Wang, Zhiming, 118, 127, 176Wankhammer, Alexander, 65Waubke, Holger, 67Weber, Frederik, 177Weber, Hansjorg, 170Weihs, Gregor, 160Weihs, Philipp, 167Weinert, Michael, 128Weiss, Ingrid, 158Werzer, Oliver, 96Widmann, Eberhard, 40, 41Wieninger, Thomas, 51Wild, Eva-Maria, 42Williams, Richard, 46, 49Windholz, Laurentius, 82, 144, 145Windisch, Andreas, 48Winkler, Adolf, 130, 168, 173–175Winkler, Georg, 147Winkler, Stephan, 41, 112, 153Wolfberger, Archim, 177Wollboldt, Petra, 170Wunderlich, Rainer, 98Wunschek, Barbara, 40Wurschum, Roland, 94, 98

YYarema, Maksym, 87, 88Ystad, Sølvi, 68

ZZaheer, Uddin, 82Zallo, Eugenio, 86Zandvliet, Harold, 123Zankel, Armin, 122Zannoni, Claudio, 162Zawisky, Michael, 152Zechner, Andrea, 166Zederbauer, Tobias, 92, 160Zeppenfeld, Peter, 129, 168Zhang, Jianjun, 155Zharnikov, Michael, 162Ziegelwanger, Harald, 69Zimmerling, Martin, 135Zmeskal, Johann, 40, 41

Zojer, Egbert, 96, 120, 162Zojer, Karin, 130, 168Zollfrank, Cordt, 157Zotter, Franz, 66Zottl, Samuel, 146Zoubi, Hashem, 78

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