Pierre Auger Observatory

Pierre Auger(1899-1993)

• Was a nuclear physics and cosmic ray physics.

• Made cosmic ray experiments on the Jungfraujoch

• Discovery of extensive air showers (1938)• He estimated the energy to 1015 eV

Location of the auger experiment

Involved countries

http://www.auger.org/collaboration/

Aim of the experiment

• Measure the energy spectrum of high energy cosmic rays up to energies of 1020 eV

• 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

• 24 Fluorescence cameras on 4 observations points

• 1600 Surface detectors (1.5 km spacing)

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 cosmic particle can be determined

Fluorescence detector

Spiegel (links) und Kamera (rechts) eines Fluoreszenzteleskops.

Surface detector

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

• Energy given in VEM (Vertical Equivalent Muon)

Cerenkov radiation

• Speed of the particle must be higher than the speed of light in the medium

• Speed of light in water = 0.75c

Combination of FD and SD

Results

Results

Results

Abb. 1: Korrelation zwischen der kalorimetrischen Energiemessung durch die Fluoreszenzmessung und dem Energieschätzer S38° des Detektorfeldes.

Results

Correlation

Red stars: Quasars or active galactic nucleiCircles: High energy cosmic rays more than 57EeV

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

Eventdisplay und Animationen

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)

Auger nord