Initial results on SiPM array based on a symmetric resistive voltage division readout

The aim of this study is to design and apply a symmetric resistive voltage division matrix to read out the compact silicon photomultiplier array (SPMArray2 by SensL) photodetector for possible applications as gamma or PET probes for localization of cancer tumors. We applied a symmetric resistive voltage division circuit, reducing the 16 voltage outputs, which are provided from SensL´s evaluation board, to 4 position signals. We acquired raw images and crystal maps from various pixilated scintillators under ^99mTc and ²²Na excitation, emitting mainly at 140KeV and 511KeV, respectively. The exact values of the resistors as well as the summing amplifiers used in the summation and division stages are given. Moreover, experimental evaluation in terms of energy and spatial resolution is reported. A clear visualization of the discrete 2mm² pixilated CsI:Tl scintillator elements under 140keV excitation - with better than 23% energy resolution - was achieved. Raw images of the crystals maps acquired shown visualization of the discrete 1mm² CsI:Na scintillator elements under 511keV irradiation. Under 511keV excitation we achieve an energy resolution of ~35% for BGO and 18% for CsI:Na pixilated scintillators, respectively. All measurements were carried out at room temperature (~25°C), without additional cooling.