High-energy gamma-ray detection with the Alpha Magnetic Spectrometer on board the International Space Station

The Alpha Magnetic Spectrometer (AMS) is a large acceptance, superconducting magnetic spectrometer designed to search for anti- matter and to study, with high accuracy, the origin of dark-matter and the composition of cosmic rays. The results of a Monte Carlo simulation study of AMS as a high-energy gamma -ray detector are presented. AMS will be able to provide accurate measurements of gamma -ray spectra over a broad energy range (up to hundreds of GeV) with energy resolution of a few per cent and angular resolution of 0.018-1 degrees . The acceptance of 0.04-0.13 m/sup 2/ sr has been estimated with maximal opening angle being 20 degrees to 42 degrees . The study of the background events has been done, the irreducible background- to-signal ratio being at the level of a few per cent or below being. The gamma -ray sky survey sensitivity of AMS is finally discussed. (14 refs).