The RICH counter of the AMS experiment

M. Buenerd
For the AMS RICH collaboration 1

Institut des Sciences Nucleaires, IN2P3/CNRS, 53 av. des Martyrs, 38026 Grenoble cedex, 

     The RICH counter of the AMS experiment will provide the mass identification of Cosmic Ray (CR) isotopes of astrophysical interest, over a wide range of momentum, up to about 12 GeV per nucleon for isotopes around 12C. In addition it will contribute to the e-(e+) vs p(p) discrimination.
     A second generation prototype incorporating the final choice of the basic components for the photodetection and the data processing (16 pixel multianode photomultiplier tubes (PMT), dedicated multiplexed readout and DSP based DAQ electronics) has been built and is currently being tested. The photodetector prototype matrix is made of 96 PMTs in approximately square geometry. Each PMT is enclosed in a plastic shell with its (16-fold) light guide system and readout electronics. The shell is housed and held in a shielding cell. The mechanical mounting of the modules is close to the final design.
     The tests are being performed with two Silica aerogel (AGL) radiators with refractive index 1.03 and 1.05, and a Sodium Fluoride radiator. Some first results (AGL 1.03) are currently available.
     The contribution will include a general presentation of the RICH in the context of the AMS project, and a description of the prototype setup. The results obtained for CR. particles will be presented and compared with the simulation results. The forthcoming beam tests schedule at CERN on next Fall will also be outlined.

1 INFN Bologna, ISN Grenoble, CIEMAT Madrid, U. Maryland, UNAM Mexico.