Time resolution of scintillation detectors based on SiPM in comparison to photomultipliers

Silicon photomultipliers (SiPM) are relatively new photodetectors studied presently by many groups in the world. Experiments requiring good time resolution are one of the areas of interest for application of SiPMs. Experiments with high photon statistics and fast picosecond lasers showed that SiPMs time resolution can be extremely good, much below 100 ps. Unfortunately, in case of a full detector with a scintillation crystal like LSO, a high capacitance of this type of devices deteriorates the rise time of the output pulse. In consequence, the timing resolution measured with the slow pulses from SiPM could be worse than results obtained with photomultipliers. In this work a detailed studies of the time resolution with scintillation detectors based on a 3×3 mm² Multi Pixel Photon Counters (MPPCs) from Hamamatsu and LSO or LFS-3 crystals are presented. Most of the measurements were done using a detector with a pixel size of 50 μm (S10362–33–050C). The results of coincidence experiments with an ²²Na gamma source are analyzed in terms of number of photoelectrons, time jitter, excess noise factor and output pulse characteristics. The aim of the work is to present timing capabilities of scintillation detectors based on MPPC in comparison with detectors based on classic timing photomultipliers.