The Max Planck Institute for Nuclear Physics in Heidelberg

Publisher:

MPI für Kernphysik, Public Relations, 2009 Editors: Dr. Gertrud Hönes, PD Dr. Bernold Feuerstein

Overview Astroparticle Physics

Quantum Dynamics

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Overview

The Max Planck Institute for Nuclear Physics (MPIK) is one of 80 institutes and research establishments of the Max Planck Society for the Advancement of Sci-ence. The MPG was founded in 1948 as successor to the Kaiser-Wilhelm-Gesell-schaft (established 1911) and is committed to basic research.

The MPIK was founded in 1958 under the leadership of Wolfgang Gentner. Its precursor was the Institute for Physics, a part of the MPI for Medical research led by Walther Bothe from 1934 to 1957. The initial scientific goals were basic research in nuclear physics and application of nuclear-physics methods concern-ing questions in the physics and chemistry of the cosmos. Since 1966 the MPIK has been led by a board of directors. Today, the activities concentrate on the two interdisciplinary research fields

Astroparticle Physics (crossroads of particle physics and astrophysics) and quantum dynamics (many-body dynamics of atoms and molecules).

Presently, the institute consists of five divisions with the directors: Prof. dr. Klaus Blaum (stored and cooled ions), Prof. dr. Werner Hofmann (particle physics and high-energy astrophysics), Prof. dr. Christoph H. Keitel (theoretical quantum dynamics and quantum elec-trodynamics), Prof. dr. Manfred Lindner (particle and astroparticle physics), Prof. dr. Joachim H. Ullrich (experimental few-particle quantum dynamics).

Additionally, there are several further research groups and, predominantly funded by third parties, junior research groups. Scientifically, the junior research groups are mostly affiliated to one of the divisions and thus broaden its research focus.

Scientists at the MPIK collaborate with other research groups in Europe, Israel, USA, Canada, Japan, and numerous other countries from all over the world. They are involved in a large number of international collaborations, partly in a lead-ing role. Max Planck partner groups at the Fudan University Shanghai and the Tata Institute for Fundamental Science emphasize the connections to scientists in China and India. Particularly close connections to some large-scale facilities like GSI with EMMI (darmstadt), dESY with CFEL (Hamburg), CErN (Geneva) and INFN-LNGS (Assergi L‘Aquila) exist.

In the local region, the institute cooperates closely with the University of Heidel-berg, where the directors and further members of the institute hold teaching posi-tions. To foster young scientists, two International Max Planck research Schools (IMPrS) have been established together with other institutes: “quantum dynam-ics in Physics, Chemistry and Biology“ and “Astronomy and Cosmic Physics“. All MPIK directors are involved in the graduate school “Fundamental Physics“ of the University of Heidelberg.

The support departments at the MPIK contribute con-siderably to the successful scientific work: precision machine and electronics shops, engineering design and media offices, network and central computing, ra-diation protection, safety and environment, library, public relations, as well as administration and facility management. Apprentices’ training shops are affiliated to the precision machine and electronics shops, where every year three or four new apprentices can be trained as “Feinwerkmechaniker Fachrichtung Feinmechanik” or “Elektroniker für Geräte und Systeme”.

As at the beginning of 2009, the MPIK staff totals 392, including 88 scientists and 122 Phd students; additionally 43 diploma students and 86 scientific guests from all over the world, most of them from russia, are working at the institute.Christoph H. Keitel, Klaus Blaum, Werner Hofmann, Manfred Lindner, Joachim H. Ullrich.

Board of Directors

Managing Director

Representative of theBoard of Directors

Scientific Advisory Board

Board of Trustees

Safety & Environment

Administration

Service Groups

Scientific Divisions

Independent and Junior Groups

OrganizationalOrganizational StructureStructure

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Theoretical Particle and Astroparticle Physics

The standard model of elementary particle physics has turned out to be very successful. It describes the behaviour of all known elementary particles: each 6 quarks (from which protons and neutrons are built) and leptons (among them elec-trons and massless neutrinos), in addition 4 gauge bosons (among them photons and gluons), and the experimentally not yet detected Higgs boson, as well as the corresponding antiparticles. The proof of neutrino masses provided the first solid evidence for “new physics” beyond the standard model. The theoretical work on this at the MPIK ranges from basic models for neutrino masses and mixings via phenomenological studies to the development of the simulation software GLoBES for present and future oscillation experiments. Theoretical insufficiencies of the standard model are also suggesting extended theories that replace the hypothetical Higgs boson by alternative mechanisms.

An exemplary topic of theoretical particle and astroparticle physics is the asym-metry of matter and antimatter in the universe (the Universe consists of matter and not of antimatter). This in fact cannot be explained by the standard model of particle physics. Several mechanisms are being discussed for it, e. g., leptogenesis. The as yet mostly unknown nature of dark matter and dark energy (of which about 95% of the universe is composed) and their cosmological implications (e.g. directly after the big bang) is a further subject. Overall, results from neutrino physics,

astroparticle physics, and experiments at accelerators are combined and used to search for direct and indirect hints on a “new physics“ beyond the standard model of particle physics. The overall aim is a more deep understanding of the fundamen-tal laws of nature.

Heavy Flavour Physics

The new Large Hadron Collider (LHC) of CErN in Geneva will help to answer the question for the origin of mass and the limits of the standard model of particle physics. The large-scale experiments ATLAS and CMS primarily search for the Higgs boson or new supersymmetric particles. The rare decays of heavy quarks are investigated with the LHCb experiment in order to gain information about the cause for the asymmetry of matter and antimatter in the Universe. A group at the MPIK has been involved in developing this detector and now focuses on the analysis of the experimental data.

Experimental Neutrino Physics

Presently, scientists of the MPIK are involved in four international large-scale ex-periments investigating different aspects of neutrino physics. The laboratory work at the institute concentrates on high-purity materials and the detection of weak-

Illustration of the grand unifica-tion. The higher the resolution of the experiment, the more uni-form is the phenomenology of the elementary particles. State-of-the-art particle detectors reach a resolution of ca. 10–18 m and thus enter the region, in which the common origin of the electromagnetic and the weak forces becomes observable. The diagram however shows that the electromagnetic and the weak interactions become increasingly rare at higher spatial resolution. Therefore, it is impossible to ad-

vance experimentally to the region of the grand unification of the electroweak and the strong forces even using the most advanced particle accelerator facilities. (Illustration: DESY press archive)

Side view of the ca. 20 m long and 10 m high LHCb detector at the Large Hadron Collider (LHC) of CERN in Geneva. The interaction zone within the storage ring is located at the right-hand side of the hall. The rate of proton-proton collisions is up to 40 MHz forming up to 70 charged particles and a similar number of high-energy gamma quanta per interaction which are registered by the de-tector. Charged particles are detected by a magnetic spectrometer and gamma quanta by calorimeters. Further detector components (Cherenkov detectors and the muon system) help to identify the particles. An elaborate trigger system extracts the rare events out of the bulk of interactions, which contain information about the physical questions investigated with the LHCb experiment. The MPIK group has contributed read-out chips for the ca. 450 000 chan-nels of all the silicon-strip counters, the read-out electronics for 270 000 channels, as well as a part of the sensors.

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est (interfering) signals, as well as on the photomultipliers for registration of the scintillation light through which neutrinos are detected. As neutrinos penetrate matter almost freely and interact with it very rarely, large and sensitive detectors are required in order to detect them.

The Borexino experiment in the Gran Sasso underground laboratory in Italy for the measurement of low-energy neutrinos started taking data in May 2007 after a long period of construction work. After only two months of measurements, the Borexino collaboration for the first time succeeded to unambiguously identify in real time neutrinos which are released in the electron capture of 7Be in the core of the Sun and thereby to verify independently neutrino oscillations.

From 2009, the neutrino-oscillation experiment double Chooz, currently under construction, will use antineutrinos from a nuclear power plant in France to in-vestigate in detail the periodic changeover between the three neutrino types elec-tron, muon, and tauon neutrino („neutrino oscillations“). In the Gran Sasso un-derground laboratory, the GErdA experiment for the search of the neutrinoless double beta decay in germanium crystals is under construction. If neutrinoless double beta decay is found, it would mean that neutrinos are so-called Majorana particles, i. e., they are their own antiparticles. The neutrino observatory IceCube is already operational while under construction at the South Pole using 1 km3 ice at depths between 1450 and 2450 m in its final state, into which strings of photo-multiplier tubes are inserted to detect neutrinos from high-energy cosmic sources.

High-Energy Gamma Astronomy

The research in high-energy gamma astronomy at the MPIK is focused on the observation of very-high-energy gamma radiation from the Universe using the H.E.S.S. (High-Energy Stereoscopic System) telescope system in Namibia. The very-high-energy gamma rays, a trillion times more energetic than ordinary star-light, are produced when charged particles are extremely accelerated, e. g., in a su-pernova explosion or in the vicinity of a black hole, and then interact with radiation fields or the surrounding medium. In contrast to the charged particles, gamma rays travel on straight lines through space, allowing us to image the sky in gamma light and to identify the sources. When entering the Earth‘s atmosphere, the gamma quanta collide with molecules producing cascades of electrically charged second-ary particles, so-called particle showers. These emit faint bluish and extremely short flashlight (Cherenkov light) which can be observed on the ground in dark moonless nights with large reflector telescopes that are equipped with fast photo-detectors. To trace the exact direction from which the particle showers come, they are observed stereoscopically by several telescopes simultaneously. The H.E.S.S. telescopes have already detected numerous, partly novel types of gamma sources and took the first spatially and temporally resolved pictures of these objects. Most of these objects are located along the galactic equator in the central part of the Milky Way. Some, however, are distant active galaxies observed in gamma light for the first time by the H.E.S.S. telescopes.

The structure of Borexino re-sembling onion-peels. The inner nylon balloon with a diameter of 8.5 m contains 300 tons of a highly pure organic liquid, in which penetrating neutrinos are scattered at electrons. Thereby electrons are excited which re-lay their energy to an organic dye (“scintillator“) which in turn emits the energy as flashlight that is detected by 2200 photo-multiplier tubes mounted at the steel sphere with a diameter of 14 m. The volume between the inner nylon balloon and the steel

sphere, split to two compartments by the outer nylon balloon, is filled with 1000 m3 shielding organic liquid. The outer shielding consists of 2400 m3 purest water in the steel tank with a diameter of 18 m.

Two of the four identical tel-escopes of each 107 m2 mirror area of the High-Energy Stere-oscopic System H.E.S.S. in the Khomas region of Namibia, operating since 2004. The loca-tion on the southern hemisphere provides optimum optical obser-vation conditions and enables a direct view into the centre of our galaxy, where many interest-ing objects are found. The four telescopes form the corners of a square of side 120 m. In the centre of the array, a fifth, much larger telescope with 600 m2 mirror area is under construction, for completion in 2010. This will strongly enhance the sensitivity of the system and extend the observable energy range to lower energies.

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Theoretical Astrophysics and Infrared Astrophysics

The work on theoretical astrophysics is in part closely correlated to the experi-mental investigations with H.E.S.S.. At the heart of this work is the quest to iden-tify and to quantitatively understand the so-called nonthermal processes, through which large fractions of the overall energy in the interstellar and intergalactic me-dium come to be carried by a small minority of relativistic particles. This energetic particle and gamma radiation is produced under extreme conditions impossible to reproduce in accelerator facilities on Earth. Known sources of cosmic radiation are exploding stars, rotating neutron stars and black holes, as well as interstellar and intergalactic shock waves.

The research at the MPIK addresses the acceleration and radiative processes in extreme astrophysical environments, the propagation of the nonthermal radiation in space, and its interaction with matter and magnetic or radiation fields. Another topic is the effect of the considerable energy densities of cosmic radiation on the evolution of structures in the universe, in particular shock waves.

Observations of the interstellar and intergalactic dust in the far infrared light by satellite instruments aboard ISO (Infrared Space Observatory, ESA) and its suc-cessor Spitzer Space Observatory (NASA) are being evaluated using theoretical models, e. g. of the dust distribution in galaxies. This is done with respect to the formation and development of gas-rich galaxies and the star formation rates in dependence on the dust distribution.

Cosmic Dust

With instruments on board spacecraft, in-situ measurements of the interplanetary and interstellar dust present in the Solar system are performed. The dust detec-tors, which were developed at the MPIK, are tested and calibrated with the dust accelerator. The sensors determine the velocity, size, and chemical composition of micrometeoroids impacting at velocities between 5000 and 1 million km/h. The sensitivity of the detectors is higher by a factor of 1000 compared to optical instruments due to the analysis of single dust grains. The most important current mission is Cassini/Huygens (NASA/ESA) in the Saturnian system where spec-tacular discoveries succeeded. For example, there is the detection of ice volcanism on the moon Enceladus, which ejects ice particles with enclosed silicates, organic compounds or salts and thus feeds the big outer dust ring of Saturn. A dust detec-tor aboard the spacecraft Ulysses orbiting around the Sun on an ellipse almost perpendicular to the planetary plane investigated until mid 2008 the interstellar dust entering the Solar system.

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Predictions of the turbulent magnetic field excited ahead of a shock front by accelerated cos-mic-ray particles. A cross-section perpendicular to the stream-ing direction of the particles is shown, with the amplitude of the generated field shown in colour from blue/black (low) to orange/red (high). The compu-tations were performed using a specially developed simulation programme. They show that cosmic rays produce a web of strong field surrounding chan-nels through which the particles can propagate rapidly. These properties are expected to have a strong impact on predictions of the spectrum of accelerated par-ticles and, hence on the gamma-ray signature they produce.

The dust detector on board of the Cassini space-craft at Saturn. The gold-plated impact detector with a diameter of 40 cm and an aperture of 45° registers high-velocity impacts of micrometeor-oids with velocities between 1 and 300 km/s and sizes of about 0.001 mm. An integrated time-of-flight mass spectrometer determines the elemen-tary composition of individual dust grains. A foil sensor determining high rates is visible for its two circular detector foils. A turntable allows aligning the instrument axis along the direction of the dust stream.

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Theory of Relativistic and Collective Quantum Dynamics in Intense Laser Fields

A detailed understanding of the interaction between all components of atomic, ionic, or molecular systems with highly intense laser fields is the goal of quantum theoretical calculations. In these fields, charged particles may become so fast that the effects of the theory of special relativity play an important role. This creates the need to search for solutions of the time-dependent Schrödinger and dirac equa-tions, the basic equations of non-relativistic and relativistic quantum mechanics, respectively. In extremely strong fields, processes of nuclear physics may occur and even new particles may be formed. Furthermore, it turns out that the vacuum is not empty (quantization of the vacuum).

An electron having been detached from an atom by field ionization in an intense laser field, is first driven away from the atom by the laser field, but then it is forced back again. This recollision may induce a further ionization of the atom and gener-ate higher harmonics of the laser frequency. In case of very high laser intensities, the electron can even reach relativistic velocities, but it is driven away from the atom by the “light pressure”, thus preventing the recollision. The theory offers the modelling of diverse procedures that circumvent this effect. Thus, collisions at much higher energies can be reached, so that, e. g., new particles may be gener-ated. Tightly focused, extremely strong laser beams permit the direct acceleration of light atomic nuclei to energies that offer potential for medical applications.

The optical properties of an ensemble of atoms can be strongly altered by expos-ing them to moderately intense laser fields which provoke quantum interference effects by resonant couplings. Among them there are electromagnetically induced transparency, lasing without inversion, or control of the refractive index. Interfer-

ences also make it possible in optical lithography to produce structures that are much smaller than the laser wavelength.

In larger ensembles of nearby atoms in strong laser fields, collective effects become important, when, e. g., during the recollision with a C60 fullerene its whole electron shell is excited entirely to perform vibrations. Collective effects may lead to the intensity of fluorescence light becoming proportional to the square of the number (instead of the number itself) of atoms, or that metal clusters absorb infrared laser light very efficiently.

Laser-Modified Quantum Electrodynamics, Nuclear and High-Energy Processes

In the framework of quantum electrodynamics, the most precise theory we have in physics, the structure of the vacuum is described and its predictions are scruti-nized with the highest precision using ion traps at the MPIK and the storage rings of the MPIK and the GSI. This makes it possible to use new methods for the meas-urement of nuclear properties. Highly precise calculations of bound states are the basis for the determination of natural constants with a relative accuracy of 10–14. quantum electrodynamics’ effects under the influence of a very strong laser field effectuate the coupling of photons to vacuum fluctuations. This is why numerous laser photons merge to a few extremely energetic photons and the vacuum gains a refractive index differing from 1.

In addition, initial theoretical studies show that a direct interaction of X-rays with pre-accelerated atomic nuclei may be induced by super-intense X-ray laser radia-tion like that of the future XFEL at dESY, and so the completely new field of nu-

In an intense infrared laser pulse, a part of the electron shell of a C60 fullerene is detached and driven back and forth by the la-ser field as a “wave packet” (rep-resented by the light-grey cloud). During the recollision with the fullerene both its remaining electrons are excited to perform vibrations and high harmonics of the laser light are emitted in the form of short-waved light pulses (blue wavy lines).

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Microscopic GeV collision of laser-guided electrons and posi-trons starting from positronium in counter-propagating laser pulses. The calculated probabil-ity distribution of the particle position is displayed (violet to red) at the instant of the colli-sion, during which muon-pair creation has been predicted theoretically. The distances be-tween the colliding particles are microscopically small (1 a.u. = 0.53 ∙ 10–10 m).

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clear quantum optics may be opened in the future. Moreover, the energy stored in a so-called metastable (i. e., energy-rich, but long-lived) atomic nucleus of a highly charged ion can be released like from an extremely energy-rich battery. Last but not least, it is possible to think of particle physics requiring relatively little space by means of high-intensity laser pulses.

Experimental Quantum Dynamics in Intense Fields

Basic principles of quantum dynamics are investigated on systems consisting of a few particles using so-called reaction microscopes, which have been developed at the MPIK. Ultra-short intense laser pulses or an electron beam break up simple molecules like H2 or atoms like He. The formed fragments are caught by large-area time- and position-sensitive detectors and their trajectories can be reconstructed therefrom. Experiments with ultra-short X-ray pulses are conducted at the free-electron laser of dESY in Hamburg (FLASH). The timescales of the thus ob-served motions are 10-100 femtoseconds (1 fs = 10–15 s). Even shorter time spans, during which light covers only atomic diameter distances, can be achieved by the bombardment of atoms or molecules with fast, charged particles, e. g. at the ac-celerator facilities of the GSI in darmstadt.

In the laser laboratory, pulses of a few femtoseconds’ duration and intensities up to 1016 W/cm² are readily available. Extremely fast processes can thus be started in pump-probe experiments and traced in time – this is how the vibration of a hydrogen molecule, one of the tiniest and fastest pendulums at all, was “filmed” for the first time. Additionally, phase-control techniques are employed that al-

low producing “tailored” laser pulses showing a desired temporal course. Higher harmonics of the laser frequency with photon energies up to 70 eV are produced using this technique and characterized in order to generate even shorter pulses with a duration in the region of attoseconds (1 as = 10–18 s). In such an order of magnitude, even the motion of electrons in atoms and molecules can be studied in a time-resolved manner. The investigation of these processes forms the basis for new techniques that may come to be applied in the future: For example, novel time and frequency standards or manipulating chemical reactions specifically with laser pulses seem possible.

Cold Molecular Ions and Ultracold Ensembles

Elementary processes of molecular ions (positively or negatively electrically charged molecules) or molecular ensembles are realized in the laboratory within strictly controlled conditions in order to reconstruct the motions of the individual building blocks. For this purpose, stored and cooled beams of molecular ions are used as they also occur in space. Very low temperatures and densities, also corre-sponding to space conditions, are a prerequisite to prepare single quantum states. Methods of investigation are the fragmentation by collision with an electron beam at low kinetic energy (dissociative recombination) in the test storage ring TSr of the MPIK or by X-ray pulses of the free-electron laser at dESY (FLASH) and the imaging of single fragmentation events with particle detectors.

Geometry of the break-up of a three-atomic hydrogen ion in the collision with electrons (e–) of thermal energy (ca. 40 K), as measured by the imaging of several hundred thousand break-up events at the ion stor-age ring TSR. The sorting of the events according to the geomet-ric parameters h1 and h2 shows a particular reaction channel, in which the H atoms prefer-ably occur in a linear arrange-ment (dark areas). The triangu-lar arrangement of the H atoms in the H3

+ molecule before the collision (centre of the diagram) mostly is strongly disturbed.

A reaction microscope in the laboratory at the MPIK for elec-tron-collision experiments. The large yellow rings are Helmholtz coils producing an axial mag-netic field in the direction of the electron beam. The atoms or molecules to be investigated are injected as a gas jet from the top into the reaction chamber where they collide with the elec-trons. The formed, positively or negatively charged fragments are guided by an additional electric field onto two large-area detec-tors where they are mapped.

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For cooling molecular ions down to temperatures of a few Kelvin, at which all molecular vibrations are frozen and only the lowest rotational levels are excited, innovative techniques using low-temperature technology and cold electron beams are being developed. Furthermore, by laser cooling in specially designed atom traps also ultracold superfluid phases, so-called quantum gases (Fermi gases or Bose-Einstein condensates), millimetre-sized atomic clouds representing one mac-roscopic quantum state, can be produced and investigated. Laser-cooled negative ions will be used to pre-cool antiprotons in order to produce and to study antihy-drogen at low temperatures.

Measurements on Stored and Cooled Ions

Highly charged atomic ions, i. e., atoms lacking most of their electrons, are of over-whelming importance for the processes in plasmas like in supernova remnants or in experiments on nuclear fusion (ionized gases, which contain to an appreciable amount free charge carriers, namely electrons and ions, are called plasmas). Up to extremely high charge states, the ions may be precisely investigated in storage rings and traps. In the storage ring, very strictly controlled electron beams are used for this purpose, whereas in an electron-beam ion trap (EBIT), at charge states up to Hg78+, also visible light and that of the free-electron laser FLASH are applied for spectroscopy.

recombination of highly charged ions with electrons only occurs at given collision energies in most cases and produces a highly excited ion or atom, whose lifetime

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and excitation energy are measured with extreme precision. The results also serve to review fundamental theories like quantum electrodynamics. Laser spectroscopy of Li+ ions circulating in the test storage ring TSr with ~5% of the speed of light made it possible to perform a precise test of the theory of special relativity.

Using single ions of light elements with only one electron (called hydrogen-like ions) trapped and cooled in a Penning trap, it is possible to determine the magnetic moment of the bound electron very accurately. This allows to precisely check the predictions of quantum electrodynamics for bound states, but vice versa, also a precise determination of the electron mass is possible.

Precision Mass Measurements

The chemical composition of our Universe shows some surprising peculiarities: The Sun mainly consists of hydrogen and helium; iron is much more abundant on Earth compared to heavy elements like gold. According to the model of nuclear physics, all chemical elements that are heavier than iron cannot have been gener-ated by nuclear fusion, but only via the capture of neutrons under extreme condi-tions. For this, there is a slow and a fast process, the latter of which is yet mostly unexplained.

Properties of atomic nuclei, in particular the mass, play an important role in the search for answers to the partly unexplained fundamental puzzles at the interface of nuclear physics and astrophysics. Extremely precise mass measurements of even

In an electron-beam ion trap EBIT (the photograph shows the installation of the MPIK at TRIUMF in Vancouver, Can-ada), positive ions are confined to a thin cylindrical volume by means of electrical and magnet-ic fields in an extreme vacuum. A focused electron beam extracts further electrons from the ions and at the same time prevents the ions to leave the trap due to its negative charge. In the direc-tion of the electron beam the trap is closed by repelling electrodes. “Evaporation” of added ions of light elements leads to cooling of

the more heavy elements, which thus remain within the trap for a longer time span and can be investigated.

In a Penning trap, ions can be stored by the su-perposition of an electrical quadrupole field and a magnetic field for very long time spans of up to several months, but in the case of radioactive nuclei often limited by the lifetime of the stored particles. The ion performs a characteristic mo-tion in the trap (circular orbit with superim-posed oscillations), from which its mass can be deduced if its charge state and the magnetic field strength are known even in the case when the exotic particles live only for a few milliseconds. At very low temperatures close to absolute zero, the measurement can be done by determining the so-called mirror current that is induced in the electrodes.

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short-lived isotopes with a relative accuracy of up to 10–8 are possible by determin-ing the cyclotron frequency of single ions stored in Penning traps. In 2008, a new radon isotope, 229rn, has been discovered and its mass and lifetime determined at the ISOLTrAP facility of CErN. Also in storage rings mass spectrometry is pos-sible. The precise determination of nuclear masses before and after a radioactive decay provides important information about the nature of the electroweak interac-tion, and thus enables also a test of the standard model of particle physics.

Accelerators and Storage Rings

For the research with fast ion beams, the MPIK operates its own accelerator fa-cilities. The MP tandem accelerator with the HF linear postaccelerator as well as the high-current injector and the 3 MV Van de Graaff generator are able to supply the heavy-ion storage ring TSr with ions of nearly all elements (from 1H to 208Pb, but also molecular ions like CH+). Beam cooling by an electron cooler or by laser beams enables a highly precise preparation of the stored ions to perform preci-sion experiments in atomic, molecular and also astrophysics. The cryogenic storage ring CSr, in which at extreme vacuum (<10–15 mbar) and a few Kelvin also heavy molecular and highly charged atomic ions will be investigated almost without any disturbances by the environment, is already under construction as the succeeding experiment.

In addition, scientists of the institute are participating in the new FLAIr and NUSTAr facilities of GSI’s future facility FAIr in darmstadt, where antimatter and exotic nuclei in quantities not yet reachable shall be produced, stored and investigated in detail.

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High voltage of more than 12 million Volts can be generated in the centre of the pressure tank of the MP tandem accelerator. Negatively charged ions from an ion source are injected, acceler-ated, and ejected again as posi-tive ions after recharging (strip-ping) with manifold energy gain (tandem principle).