A SiPM based readout system for shashlik calorimeters: Status and perspectives

In recent years Silicon Photomultipliers (SiPMs) have been proposed as a new type of readout system for scintillating detectors in many experiments. SiPMs consist of a matrix of parallel-connected silicon micro-pixels, which are independent photon counters working in limited Geiger mode with very high gain (~10⁶). This contribution presents the use of SiPMs (manufactured by FBK-irst) as a readout system of scintillator-lead shashlik calorimeters. The calorimeter under test is composed of 130 tiles (65 of scintillator and 65 of lead) with an area of 11.5×;11.5 cm² and a total thickness of ~18 radiation lengths. The scintillation light is readout using 144 wavelength-shifter (WLS) fibers with a diameter of 1.2 mm and brought to large area SiPMs, characterized by a high dynamic range (6400 pixels). A custom board based on the MAROC3 ASIC has been used for the readout of the SiPMs signals. The performances of the calorimeter and of the readout system have been tested at the CERN PS-T9 and the SPS-H2 beamlines with electrons up to 150 GeV.