Performance of the AMS-02 Experiment for High Energy Gamma Ray Astrophysics

AMS is a particle detector designed to perform high precision measurements of the cosmic rays fluxes with the main goals of searching for anti-nuclei, as remnants of primordial anti-matter, and of measuring the faintest components of the cosmic flux, anti- protons, positrons and high energy photons. To fulfill the requirements of large acceptance, long exposure time and excellent particle identification needed to achieve the intended results, AMS will operate in space as an attached payload to the International Space Station (ISS), being the first full featured particle physics experiment to operate in the Earth orbit. The AMS-02 accurate measurements of cosmic-ray nuclei, protons, antiprotons, electrons and positrons will be completed by high energy gamma rays detection. The experiment will detect gamma-rays, either by reconstructing e+e− pairs generated by photons converted upstream the tracker (conversion mode), or based on direct identification of electromagnetic showers in ECAL (calorimetric mode). This thesis can be seen as the merging of three specific subjects: 1) the construction of the AMS-02 tracker detector through the clean room work on silicon ladders; 2) the test beam data analysis to test the performance of a “minitracker” in detecting converted photons and providing also the measurement of the momentum resolution and the validation of previous measurements on spatial resolution; 3) the computation of the exposure maps, with their usage inside a photon fast simulator program, and the AMS-02 sensitivity to detect gamma-ray sources, in particular pulsars. All of these items contribute to an unique study: the AMS-02 capability to detect gamma-ray photons.