Pile-up discrimination method applied to novel gamma-ray detectors based on SiPMs arrays

SiPMs-based gamma ray detectors have shown a significant development impulse in recent years due to a number of advantages, namely: good time response, small size, magnetic field immunity and low cost. We have designed a special SiPM array formed by 12×12 SiPMs of 3×3 mm2 active area (FB-30035, SensL) that covers a total photosensor area of 5×5 cm2 for gamma ray detection in PET scanners. When thick crystals are considered, pile-up events increase with the scintillation material volume leading to a loss of events and spatial distortions in the image.