Wuppertal 2015 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 73: Kosmische Strahlung IV
T 73.2: Vortrag
Mittwoch, 11. März 2015, 17:00–17:15, I.12.01 (HS 30)
Towards an antiproton measurement with AMS-02 — •Andreas Bachlechner — RWTH Aachen University
AMS-02 is a multi-purpose high-precision particle detector. It has been onboard the International Space Station since May 2011.
The antiprotons measurement is an important part of the AMS-02 physics program. An excess above the expected spectrum due to interactions of cosmic rays with the interstellar matter can hint at exotic sources like dark matter annihilation. The antiproton-to-proton ratio and the antiproton flux itself may also improve the understanding of the origin and propagation of cosmic rays.
Due to the very small fraction of antiprotons in the cosmic radiation of about 10−5 compared to protons a very precise particle identification is needed. The main backgrounds are other singly charged particles like protons, electrons, and pions produced within the detector material itself. At lower energies the ring-imaging Cherenkov detector and the time-of-flight system help to separate light particles from protons. The electromagnetic calorimeter and the transition radiation detector redundantly suppress the electron background. The reconstruction of the charge sign by the magnetic spectrometer is limited by its resolution and has to be taken into account carefully.
The strategies to identify antiprotons in the cosmic-ray measurement in different energy regions will be presented. Methods to suppress and the effect of the backgrounds to the antiproton-to-proton ratio will be discussed.