The Alpha Magnetic Spectrometer (AMS) is a high energy particle physics experiment to search for antimatter, dark matter, strangelet and for precise measurement of cosmic-rays on the International Space Station (ISS) for more than ten years. Since the experiment is performed outside of the earth atmosphere and because of its long duration measurement, it is expected to give us unprecedented precise results of TeV scale cosmic-rays.
One of the goals of this experiment is to search for dark matter, the most favored candidate of dark matter is neutralino. According to the supersymmetry, neutralino could annihilates into electron and positron pair. Thus, we could search for the existence of dark matter from anomalous features in the positron and electron spectra. Since the cosmic-rays consist of 90% of protons approximately, it would be inevitable to have proton contamination in the positron sample. The main purpose of this thesis is to understand performance of Transition Radiation Detector (TRD) in AMS-02 by measuring the proton rejection power using the AMS-02 real data taken from 20th of May, 2011 to 20th of October, 2011. The obtained proton rejection power at 90% electron efficiency is 2447±0.33%(stat. err.) and systematic error less than 1%.
Such a result came from the analysis with a TRD performance alone. Based on this result, we could expected to reject protons with better efficiency if we combine informations from the other detectors such as Electromagnetic Calorimeter (ECAL) and Ring Image Čerenkov Detector (RICH) together.
Thesis Advisor: Prof. Guinyun Kim