Tests of a silicon photo-multiplier module for detection of Cherenkov photons

The present work investigates the potential of silicon photomultipliers as position sensitive detectors of single photons in a ring imaging Cherenkov counter. The main advantage of silicon photomultipliers is their insensitivity to high magnetic fields, so they can be used inside large magnetic spectrometers. A module, consisting of 64 (=8x8) Hamamatsu MPPC S10362-11-100P silicon photomultipliers, has been constructed and tested with Cherenkov photons emitted in an aerogel radiator by 120 GeV/c pions from the CERN T4-H6 beam. In order to increase the efficiency, i.e. the effective surface on which light is detected, we have made and tested pyramidal light concentrators. The results of these tests indicate that a RICH counter based on silicon photomultipliers is feasible.