New results from a test of silicon photomultiplier as readout for PET

The silicon photomultiplier (SiPM) is a novel photon detector based on Geiger mode operating avalanche photodiodes. In this paper we present experimental results which show that SiPMs can be used in positron emission tomography (PET). As scintillator we use the newly developed LYSO material, which has very similar characteristics to the widely used LSO. With our setup we measure an energy resolution of (21.5±0.5)% and a coincidence time resolution of (1.51±0.07) ns, both full width at half maximum. A significant improvement in time resolution could be achieved by triggering on the first photoelectron in the signal. We also present the coincidence rate of two detector channels vs. the position of a small pointlike ²²Na positronium source.