Characterization of Silicon Photomultipliers for PET Imaging

The Silicon Photomultiplier (SiPM) is a novel photodetector being developed for high energy physics applications. SiPM is attractive for PET imaging because it is compact; provides high gain at low voltage; is insensitive to magnetic fields; has a fast timing response; and is potentially inexpensive and CMOS-technology compatible. Researchers have characterized SiPM performance mostly in areas relevant to high-energy physics and astrophysics applications, with some findings demonstrating the potential usefulness of SiPM in positron emission tomography (PET) imaging. Using our photodetector characterization test-stand equipped with a 20 GSps sample rate and 6 GHz bandwidth oscilloscope, we have measured the gains in the range of 1-3 times 10⁵ room temperature for SiPM samples obtained from different producers. We have measured the rising times and their standard deviations. Based on the measured dark-count rates at room temperature, we have also estimated the achievable energy resolution of SiPM in PET imaging when used with LSO and BGO scintillators.