Pierre Auger Observatoryand

KASCADE-Grande

Dr. Frank Morherr

Pierre Victor Auger (1899-1993)• He was the discoverer of giant airshowers generated by the

interaction of very high-energy cosmic rays with the earth's

atmosphere.• His Fields of experimental physics were

– Atomic physics (photoelectric effect);

– Nuclear physics (slow neutrons);

– Cosmic ray physics (atmospheric air-showers). – Cosmic ray physics (atmospheric air-showers).

– Made cosmic ray experiments on the

Jungfraujoch

• Discovery of extensive air showers (1938)

• He estimated the energy to 1015 eV

• After the war, he became

Director of the Department

of Sciences for UNESCO.

Location of the auger experiment

Auger Observatory

Involved15countries

Cosmic Rays

• Cosmic rays are energetic charged subatomic particles, originating from outer space.

• Produce secondary particles that penetrate the Earth's atmosphere and surface.� 89% of cosmic rays are protons or

hydrogen nuclei� 10% are helium nuclei or alpha particles� 10% are helium nuclei or alpha particles� 1% are heavier elements

• Cosmic rays can have energies of over 1020 eV, far higher than the 1012 to 1013 eV that terrestrial particle accelerators can produce

• From where do they come� unknown superpowerful cosmic explosion?�huge black hole sucking stars to their violent deaths?�From colliding galaxies?

Aim of the experiment• Pierre-Auger-Observatorium worldwide greatest installation

for Measurement of cosmic Rays

• Surface detectors mesure the secondary particles. They detects high energy particles through their interaction with water placed in surface detector tanks

• Telescope tracks the development of air showers by observing ultraviolet light emitted high in the Earth's atmosphere.

• Determine the direction of these cosmic rays

• Determine the element composition of cosmic rays

• Study of extensive air showers

The experiment• Detector field: 3000 km2

• 30 Times the size of Paris

• 24 Fluorescence cameras on 4 observations points

• 1600 Surface detectors (1.5 km spacing)km spacing)

• Each 3000-gallon (12000 liter) tank, separated from each of its neighbors by 1.5 kilometers, is completely dark inside - except when particles from a cosmic ray air shower pass through it.

Fluorescence detector• Charged particles in an air

shower also interact with atmospheric nitrogen (excitation)

• Emitted ultraviolet light via a process called fluorescence

• Direction and energy of the • Direction and energy of the cosmic particle can be determined

• The fluorescence detectors much more sensitive than the human eye can "see" distant air showers develop

• Using a grid of focusing mirrors to collect the light, cameras can view the air shower up to 15 kilometers away.

Fluorescence detector

Mirrorreflector 12m² (left) and Camera with 440 Photomultipliers(right) of a Fluorescence detector

Surface detector

• Energetic Particles of a showerProduce short light flashes in the Water, so called cherenkov-light

• Three sensitive photomultiplier register emissions in each tank.

• Air showers are detected at the spatially and temporally coincident measurement of particles in several tanks.

Surface detector• Base of detector = 10m2

• 12 tons of very pure water as detection material

• 3 Photomultipliers detect cerenkov signals

• With GPS antenna high time correlation to different detectors correlation to different detectors

• Energy given in VEM (Vertical Equivalent Muon)

• Autonomic Stations with solar energy

• Communication with Microwaves

Cherenkov radiation• Speed of the particle must

be higher than the speed of light in the medium

• Speed of light in water = 0.75c

• The charged particles polarize the molecules of polarize the molecules of that medium, which then turn back rapidly to their ground state, emitting radiation in the process

• The characteristic blue

glow of nuclear reactors

is due to Cherenkov radiation.

Combination of FD and SDProof of the particles is very complex because they are very rare: At these energies, one expects roughly one particle per square kilometer per century. Therefore, huge detector surfaces are needed to find a sufficient number of these particles. This is done indirectly, by them in the atmosphere triggered cascade of secondary particles, the air showers.

Results

Results

Results• The observation of showers with several telescopes and the

simultaneous measurement of the particles in the water tanks impressively demonstrate the efficiency of the Auger Observatory.

• First scientific results include an energy spectrum of observed events, the survey of the southern sky for point sources and an upper limit for the proportion of photons in the ultra-high energy cosmic rays

• A in various models predicted point source near the galactic center • A in various models predicted point source near the galactic center could not be confirmed.

• In November 2007, it was announced that the observatory had found a correlation between the 27 highest energy events and nearby active galactic nuclei (AGN).

• Would suggest that these events are triggered by protons that were emitted by objects correlated with the AGN distribution of matter. Acceleration by the large magnetic fields associated with the massive central black holes that form the AGNs is one possibility.

Results

Correlation between the calorimetric energy measurement by the fluorescence measurement and the energy estimator S 38 ° of the detector field.

Results

The preliminary energy spectrum of the Auger Observatory as it is presented at conferences since mid-2007. Energy spectrum shows a precipitous decline, as would be expected from the GZK effect. This conclusion is only permitted if the energy spectrum, the elemental composition and anisotropy measurements thus provide a coherent picture as an early waning of the accelerator can beexcluded.

GZK-Cutoff: Named by Greisen, Zatspin and Kuzmin, predict that cosmic rays withEnergies of 5* 1019 would interact with the cosmic microwave backround, so itdecreases

Correlation

Red stars: Quasars or active galactic nucleiCircles:High energy cosmic rays more than 57EeV (57*10^18eV)

Arrival direction of the 27 highestenergetic cosmic ray particles detected by the Pierre Auger Observatory Aitoff shown in a projection of the celestial sphere in galactic coordinates. The energies of the cosmic primary particles are larger than 57 x 10 ^ 18 eV (57 EeV). They are shown as circles with a radius of 3.1 degrees. The position of 472 AGNs with a maximum distance of 75 megaparsecs are marked as * red. The blue bands denote the field of view of the Pierre Auger Observatory: the darker the blue the greater the exposure of the experiment. The solid line marks the edge of the field of view and corresponds to a maximum zenith angle of 60 degrees. Centaurus A, the Earth is closest to the AGN with a white * marked. Two of 27 cosmic particles are less than 3.1 degrees from it. The super-galactic plane is shown as a dashed line. She refers to a region with a large number of nearby galaxies, including some with an active nucleus.

Correlation• Rejected the hypothesis of isotropic distribution of cosmic

rays above 6 x 1019 eV

• Very high cosmic particles have extragalactic origin

• Higher flux of cosmic particles from the galactic centers and Quasars

Elemental composition

Light particles such as protons (left) produce showers that usually develop

deeper in the atmosphere triggered by heavy primary particles (iron cores,

right) as a longshoreman. The comparison of showers observed with the

fluorescence detectors of the Pierre Auger Observatory, enables these theoretical

predictions, draw conclusions about the elemental composition of cosmic rays.

Mean measured atmospheric depth of shower maximum with the

Pierre Auger fluorescence telescopes (red dots) are compared

with theoretical predictions for iron nuclei (blue lines) and

protons (red lines)

Status and planned upgrades• Increase the density of the surface detectors to get a better

study of low energy cosmic rays (1015 eV)• Detection of extended air showers with radio antennas• Realization of the Auger detector at the northern hemisphere

(Colorado)• By the end of 2005, about 1050 water tanks and 18 telescopes

of the southern Auger Observatory was set up. Since the beginning of 2008 it is completed. It has an approximately 30-beginning of 2008 it is completed. It has an approximately 30-times larger detector area than the largest AGASA air shower experiment in Japan.

• Next, the structure of the northern observatory was planned. A complete and uniform coverage of all possible directions is crucial to the interpretation of the data. Place for the Northern experiment was selected by the Auger Collaboration, in Lamar

• Today, nearly 500 physicists from more than 90 institutions in 19 countries around the world are collaborating to operate the southern site.

KASCADE-GrandeResearch Center Karlsruhe (Germany)

Field array (200m x 200m) consists of 252 detector stations arranged on a rectangular grid with a distance of 13 meters to each other. 16 (resp. 15) of the stations form a so-called cluster with an electronics container in the center and which act as an independ shower experiment. In the middle of the array one can see the building with the KASCADE central detector.

What is KASCADEWhat is KASCADE--Grande ?Grande ?

• KASCADE-Grande is the extension of the Extensive Air Shower detector array KASCADE, realized to expand the energy range for cosmic ray studies from 1014-1017 eV primary energy range up to 1018 eV.

• This is performed by extending the area covered by the KASCADE electromagnetic array from 200×200m2 to 700×700m2 by means of 37 scintillator detector stations of 10 700×700m by means of 37 scintillator detector stations of 10 m2 active area each.

• This new array is named Grande and provides measurements of the all-charged particle component of extensive air showers, while the original KASCADE array particularly provides information on the muon content.

• Additional dense compact detector set-ups being sensitive to energetic hadrons and muons are used for data consistency checks and calibration purposes.

(KArlsruhe Shower Core and Array

DEtector-Grande)

Why KASCADE-Grande ?• Experiment allows to measure the energy and mass of cosmic rays

only indirectly through their influence on the shower development and shape determine

• Through extensive computer simulations with the Karlsruhe simulator CORSIKA showers can establish relationships between the measured shower shape on the ground and the mass and energy of the primary particle generating

• From the slightly varying arrival times of individual stations it can • From the slightly varying arrival times of individual stations it can also determine the direction of the primary, as the rain front perpendicular to the flight direction of the primary stands. The front is also slightly curved: and this curve is reconstructed from the arrival times

• Reconstructed data from the showers can now derive the energy and mass-producing the cosmic particle. The energy is determined by the radial density function, with the conversion again depends on the simulation results. In order to reconstruct the mass of the muon to electron ratio, and the front curvature is used.

Motivation of KASCADEMotivation of KASCADE--GrandeGrande

Primary ParticlePrimary ParticlePrimary ParticlePrimary Particle

Earth‘s AtmosphereEarth‘s AtmosphereEarth‘s AtmosphereEarth‘s Atmosphere

AirAir--showershowerAirAir--showershower

ProductionProduction

Acceleration, PropagationAcceleration, Propagation

InteractionInteraction

What is the origin of the knee?What is the origin of the knee?

Is the knee positionIs the knee positionrigidity dependent?rigidity dependent?

What is the origin of the knee?What is the origin of the knee?

Is the knee positionIs the knee positionrigidity dependent?rigidity dependent?

ReconstructionReconstruction

QuestionsQuestions

Motivation of KASCADEMotivation of KASCADE--GrandeGrandeMeasure as many observables as possible

Reconstruct properties of primary from observables

Multi-Detector system neededneeded

Example:

• Measure Ne and Nµ

• Simulate Ne and Nµ

• Compare simulation and measurement

• Reconstruct primary species and energy

Overview of the BuildingsOverview of the Buildings

Arrangement of the KASCADEArrangement of the KASCADE--Grande Grande DetektorsDetektors

The Central DetectorThe Central DetectorHadron-Calorimeter, 9 layers of liquid ionisation chambers (Hadrons)

Triggerplane, plastic scintillators (µ)

Topcluster, plastic scintillators (µ)

Multi Wire Proportional Chambers (µ)

Limited Streamer Tubes (LSTs, µ)Limited Streamer Tubes (LSTs, µ)

The Central DetectorThe Central DetectorHadron-Calorimeter, 9 layers of liquid ionisation chambers (Hadrons)

Triggerplane, plastic scintillators (µ)

Topcluster, plastic scintillators (µ)

Multi Wire Proportional Chambers (µ)

Limited Streamer Tubes (LSTs, µ)Limited Streamer Tubes (LSTs, µ)

Most important observables:

Hadron energies

Hadron tracks

Muon Tracking Detector (MTD)Muon Tracking Detector (MTD)

Limited Streamer Tubes, 32 m x 5.4 m x 2.4 m

2 rows of 8 towers with 3 layers of horizontal LSTs each

2 additional vertically mounted rows of LSTs

Muon-tracking with 0.35° precession

Threshold at 800 MeV for vertical Muons

Muon Tracking Detector (MTD)Muon Tracking Detector (MTD)

Most important observables:

Muon tracks

Muon production heights

Limited Streamer Tubes, 32 m x 5.4 m x 2.4 m

2 rows of 8 towers with 3 layers of horizontal LSTs each

2 additional vertically mounted rows of LSTs

Muon-tracking with 0.35° precession

Threshold at 800 MeV for vertical Muons

The KASCADEThe KASCADE--ArrayArray16 clusters at 200 x 200 m2

12 outer clusters à 16 stations with e/γ- and µ-detectors

4 inner clusters à 15 stations with e/γ-detectors

e/γ-detectors: 4 liquid scintillators with PMT-readout(1) per station

µ-detectors: 4 plasticscintillators, 90 x 90 cm2 withPMT-readout per station

(1) Output of a photomultiplier and converting in a digital data signal is called PMT readout methods or gated integrator,continous current, and photon counting.

The KASCADEThe KASCADE--ArrayArray16 clusters at 200 x 200 m2

12 outer clusters à 16 stations with e/γ- and µ-detectors

4 inner clusters à 15 stations with e/γ-detectors

Most important observables:

Electron numbers (Ne)

Muon numbers (Nµ)

e/γ-detectors: 4 liquid scintillators with PMT-readout(1) per station

µ-detectors: 4 plasticscintillators, 90 x 90 cm2 withPMT-readout per station

The GrandeThe Grande--ArrayArray

37 stations arranged in 0.5 km2 hexagonal grid

Average distance of 137 m

Electronically connected to 18 trigger-hexagons

(2) minimum ionizing particle

16 plastic scintillators of 10 m2

per station

Two channels (high and low gain)

Therefore large dynamic range(0.03 – 3000 m.i.p.(2)/m2)

Measures primaries up to 1018 eV

The GrandeThe Grande--ArrayArray

37 stations arranged in 0.5 km2 hexagonal grid

Average distance of 137 m

Electronically connected to 18 trigger-hexagons

(2) minimum ionizing particle

16 plastic scintillators of 10 m2

per station

Two channels (high and low gain)

Therefore large dynamic range(0.03 – 3000 m.i.p.(2)/m2)

Measures primaries up to 1018 eV

Most important observables:

Numbers of charged particles

Energies of charged particles

Piccolo and LopesPiccolo and LopesPiccolo:

8 stations, arranged in a circle of 0.1 km2

12 plastic scintillators(320 cm x 30 cm x 3 cm) per station

Used as trigger source for all other components

Lopes:other components

Prototype array of 10 antenna

Measuring radio emission in air showers

Advantages:

� See development of EAS

� High duty cycle

� Economical

Overview of the DetectorsOverview of the Detectors

Particles Sensitive area (m2)

e/µ 370

e/µ 80

µ, Ethresh=800 MeV 3 x 128MTD

Detector

Grande-Array

Piccolo

KASCADE-Array

Liquid scintillators e 490

Plastic scintillators µ, Ethresh=230 MeV 622

Trigger plane µ, Ethresh=490 MeV 208

MWPCs/LSTs µ, Ethresh=2.4 GeV 3 x 129

Calorimeter Hadrons, Ethresh=10-20 GeV 9 x 304

Central Detector

KASCADE-Array

Results

Results