A multichannel compact readout system for single photon detection: Design and performances

Abstract Optimal exploitation of Multi Anode PhotoMultiplier Tubes (MAPMT) as imaging devices requires the acquisition of a large number of independent channels; despite the rather wide demand, on-the-shelf electronics for this purpose does not exist. A compact independent channel readout system for an array of MAPMTs has been developed and tested [1] , [2] . The system can handle up to 4096 independent channels, covering an area of about 20 × 20 cm 2 with pixel size of 3 × 3 mm 2 , using Hamamatsu H-9500 devices. The front-end is based on a 64 channels VLSI custom chip called MAROC, developed by IN2P3 Orsay (France) group, controlled by means of a Field Programmable Gate Array (FPGA) which implements configuration, triggering and data conversion controls. Up to 64 front-end cards can be housed in four backplanes and a central unit collects data from all of them, communicating with a control Personal Computer (PC) using an high speed USB 2.0 connection. A complete system has been built and tested. Eight Flat MAPMTs (256 anodes Hamamatsu H-9500) have been arranged on a boundary of a 3 × 3 matrix for a grand total of 2048 channels. This detector has been used to verify the performances of a focusing aerogel RICH prototype using an electron beam at the Frascati (Rome) INFN National Laboratory Beam Test Facility (BTF) during the last week of January 2009. Data analysis is ongoing: the first results are encouraging, showing that the Cherenkov rings are well identified by this system.