Space application: The AMS RICH

A Ring Imaging Cherenkov detector is on board the Alpha Magnetic Spectrometer, for mass and charge identification of charged cosmic rays. AMS is a high-energy particle physics magnetic spectrometer in space, which was successfully installed at the International Space Station on May 2011 to perform accurate measurements of Galactic Cosmic Rays fluxes in the rigidity range from 1 GV to a few TV. The RICH detector provides AMS the capability to measure the light nuclei isotopic composition of CRs, in the kinetic energy range from a few GeV/nucleon to about 10 GeV/nucleon, so far largely uncovered by previous experiment. In addition, the RICH is a key detector in indirect search for Dark Matter looking at the antiproton and anti-deuteron rare species. The detector has shown stable response during the past 8 years of continuous data taking and no significant indication of degradation has been observed. Once accounted for the extreme environmental conditions of the detector in space and their variation in time, the performances in velocity end charge measurements match the requirements. The different stages of the AMS-RICH construction, from design to commissioning through space qualification and characterization tests, are addressed in this paper, in the aim of highlighting the important aspects which contributed to the success of this detector, only of its kind operative in a long duration mission in space.