Pierre Auger Observatory

Pierre Auger( ) 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 eV

Location of the auger experiment

Involved countries

Aim of the experiment Measure the energy spectrum of high energy cosmic rays up to energies of 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 km 2 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. Licht auf einer grossen Spiegelfläche von etwa 12 Quadratmetern gesammelt, auf eine Kamera mit 440 Photonenvervielfachern gebündelt und dort alle 0.1 Mikrosekunden aufgezeichnet.

Surface detector

Base of detector = 10m 2 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

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

Results

Correlation Red stars: Quasars or active galactic nuclei Circles: High energy cosmic rays more than 57EeV

Correlation Rejected the hypothesis of isotropic distribution of cosmic rays above 6 x 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 (10 15 eV) Detection of extended air showers with radio antennas Realization of the Auger detector at the northern hemisphere (Colorado)

Auger nord