Software-based digital pulse processing for Silicon Photomultiplier radiation detectors

A Silicon Photomultiplier (SiPM) was used for the optical readout of a stilbene single-crystal scintillator for pulse shape discrimination (PSD) of fast-neutrons and gammas. We are developing digital pulse processing (DPP) techniques for the optimal handling of SiPM signals in the presence of noise intrinsic to these devices. The DPP is based on a weighted integration, with the optimal processing parameters found using genetic algorithm heuristics. Efficient PSD was measured at energies of 165 keVee and above using the optimized DPP, a significant improvement over the digital charge comparison method, which provided efficient PSO only above 395 keVee. The successful application of PSO using SiPM and OPP opens up the PSO technique for a new range of applications where the SiPM´s small size, low power and cost are beneficial.