Pierre Auger Observatory

The Pierre Auger Observatory is an international physical large-scale experiment to study cosmic rays at the highest energies.

History, experiment and build

The observatory was designed in 1992 by the Nobel Prize winner Jim Cronin and Alan Watson and after the French physicist Pierre Auger, who in 1938 discovered extensive air showers, named.

The observed radiation window is located in the energy range from 1017 eV to 1020 eV (electron volts). The radiation is mainly composed of protons, rarely heavier nuclei that generate upon impact with the atmosphere, a plurality ( more than 106 ) on the other particles. This cascade of particles is called air showers. There is no longer directly observable with satellite or balloon experiments at energies above about 1014 eV cosmic rays, the Pierre Auger Observatory observed these showers and thus the cosmic rays only indirectly.

The Pierre Auger Observatory was built in the Pampa Amarilla near the small town of Malargüe, Argentina and officially opened in November 2008 in the presence of Jim Cronin. The test facility consists of two independent detector systems, the surface detector (SD, after closely. Surface Detector ) and the fluorescence detector ( FD).

The surface of the detector (SD)

The surface detector consists of 1600 stations, each with 1500 meters distance in an area of ​​about 3000 km2 on a plateau about 1400 m above sea level are placed in a triangular pattern. Each station consists of a container filled with 12 m3 of high-purity water tank in which incident particles produce Cherenkov radiation. This is recorded by three photomultipliers in the tank cover. An air shower produces a signal in several tanks. From strength and timing of individual signals can then be closed on energy and direction of the primary particle.

The fluorescence detector (FD)

The fluorescence detector consists of 27 telescopes that overlook of four sites from the surface of the detector field. The fluorescence detector was registered by the chill in the atmosphere generated fluorescent light. Thus, the development of the shower be traced and be deduced properties of the primary particle, regardless of the surface detector.

The fluorescence light produced is very weak, so the fluorescence detector can be operated only during moonless nights, which make up about 13 % of the time. This low operating time is offset by an opposite surface of the detector significantly higher accuracy.

Partial release of the data

The Pierre Auger Collaboration has decided to make 1 % of the data publicly available. On a web page, which is updated daily, the events collected since 2004 can be displayed.

First results

The first observations of high energy cosmic rays above show a clustering of cases from the direction of the centers of active galactic nuclei. It is therefore obvious that they are thrown with the energy of black holes in the centers of galaxies into space. This results in new questions, so an increased incidence of muons is measured, which does not fit into the existing air shower models.

German members of the Pierre Auger Observatory

  • RWTH Aachen
  • Max Planck Institute for Radio Astronomy, Bonn
  • University of Hamburg
  • Karlsruhe Institute of Technology
  • University of Siegen
  • University of Wuppertal
James Cronin Pierre Victor Auger Atomic nucleus Air shower (physics)
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