The AMS silicon tracker

The Alpha Magnetic Spectrometer (AMS) is designed to operate on the International Space Station (ISS) for a long duration measurement (3 yr) of the cosmic ray spectra in the rigidity range from similar to 0.1 GV to several TV. At the detector level, the principal innovation is the use of a large area (7 m(2)) silicon microstrip tracker. A first version of the AMS was flown on the NASA space shuttle Discovery in June 1998. A description of the detector and a brief review of selected performance results from the test flight are presented.