Preliminary study of different readout strategies for a positron emission mammograph head

We are developing a positron emission mammograph imaging system that consists of 2 planar heads (10×10 cm2), each composed of 4 matrices (5×5 cm2) of scintillating crystals coupled to the same number of multi-anode PMT (Hamamatsu H8500). We are developing a readout scheme which handles the 4×64 output signals of each head. We are primarily interested in charge multiplexed readout schemes. The measurements presented in this paper highlight the limits of a multiplexed readout using a discretized positioning circuit (DPC) by comparison with results using either another multiplexed scheme based on symmetric charge division (SCD) or a multi-anode readout. The measurements have been performed with the H8500 PMT coupled to pixelated NaI(Tl) and YAP crystals.