The SiPM — A new Photon Detector for PET

We have studied a novel semiconductor photon detector (silicon photomultiplier) as a readout for LSO scintillator crystals used in PET detectors. Silicon photomultipliers (SiPMs) of a (1×1) mm2 area were coupled to LSO crystals of (2×2×10) mm3. Two elements were exposed to a 22Na positron source emitting two 511 keV gamma quanta. Coincidence studies yielded a FWHM of the photopeak spectrum around 35% and a time resolution of 3 ns. Extrapolating from the large area mismatch in the readout area allows us to conclude that the novel SiPM is a very promising element for PET applications.