Göttingen 2012 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 115: Experimentelle Techniken der Astroteilchenphysik 3

T 115.1: Vortrag

Mittwoch, 29. Februar 2012, 16:45–17:00, VG 0.110

Identification of positrons and electrons in AMS-02 experiment — •Valerio Vagelli, Wim De Boer, Iris Gebauer, Melanie Heil, Simon Kunz, and Olga Pfeifer — Institut für Experimentelle Kernphysik KIT, Karlsruhe (DE)

Alpha Magnetic Spectrometer AMS-02 is a large acceptance cosmic ray detector which has been installed in the International Space Station ISS in May 2011, where it will measure the fluxes of cosmic rays up to TeV energies for more than 10 years.

A primary cosmic ray research topic is the indirect search for Dark Matter DM in the positron channel. Several experiments have shown a rise in the positron against electron ratio for energies above 10 GeV, which can be interpreted as a signal from DM annihilation. However, astrophysical hypothesis such as local pulsars can also explain this feature. In order to resolve the contribution of the different sources, highly accurate data in the 100 GeV - 1 TeV energy range are required. AMS-02 is exploring spectra in this energy range, to confirm and extend the actual status of research.

An important systematic for this measurement is the subtraction of the proton background in the positron sample. Two AMS-02 subdetectors are used for this aim: the Transition Radiation Detector TRD and the Electromagnetic Calorimeter ECAL. Their combined separation power allows to identify positrons with a high proton rejection power.

We introduce a Neural Network based discrimination algorithm for TRD and ECAL developed using flight data, with an overview of its performances and applications.