The AMS tracking detector for cosmic-ray physics in space

AMS-02 is a general-purpose spectrometer designed to measure cosmic rays and gamma rays in near-Earth orbit. The main scientific motivations are the search for cosmic anti-matter, the search for dark matter, precision measurements on the relative abundance of different nuclei and isotopes, as well as the measurement of very high-energy gamma rays. Constructed by a large international collaboration of institutes from America, Asia and Europe, it will collect data on the International Space Station for a period of at least three years. s contribution, I first identify the various detector requirements necessary to carry out this ambitious program. In particular, a large-area silicon microstrip detector inside a 0.8 T superconducting magnet is well suited to measure rigidity p / Z and specific energy loss dE/dx of cosmic rays, as well as the direction and energy of converted gamma rays. I review the advantage of such a silicon-tracking detector, taking into account the constraints of the space environment. llaboration has gained extensive operating experience with double-sided silicon sensors in beam tests, and above all with AMS-01, a precursor spectrometer flown in the cargo bay of the Shuttle Discovery. During the entire 10-day STS-91 mission, the Silicon Tracker functioned without fault and with good spatial resolution. he lessons learned with AMS-01, improvements were made to the design and assembly procedure of the 2500 sensors of AMS-02. As a result, the charge identification has been extended from Oxygen ( Z = 8 ) to Iron ( Z = 26 ). The physics reach of the new spectrometer is presented.