Power-efficient high-frequency readout concepts of SiPMs for TOF-PET and HEP

Abstract

Recent SiPM developments, together with improved readout electronics, opened new doors in time of flight positron emission tomography (TOF-PET) and high energy physics (HEP) research with a focus on prompt photon detection with inorganic scintillators. For instance, the relatively high Cherenkov yield of Bismuth Germanate (BGO) upon 511 keV gamma interaction has triggered a lot of interest, especially for its use in total-body PET scanners due to the relatively low production costs of BGO. However, especially in TOF-PET, the electronic readout for BGO still poses unsolved problems. Lab experiments have shown the benefit of Cherenkov detection, with coincidence time resolutions (CTRs) <200 ps FWHM achieved, but lack system integration due to an unacceptably high power consumption (≫30 mW) of the used amplifiers. Therefore it becomes necessary to investigate different readout concepts of modern analog SiPMs, for which we tested several high-bandwidth amplifiers, commercially available, small in dimension, cheap and with a power consumption ranging from 288 mW to only 17 mW. We found that all tested amplifiers showed similar CTR performance of ∼100 ps FWHM coupling 3×3×3 mm3 LYSO:Ce cubes from EPIC-crystals to S14160-3050HS Hamamatsu SiPMs with 3×3 mm2 active area. The CTR performance with BGO is comparable for all tested amplifiers and the noise contribution to the CTR is found negligible. The results obtained lead to the conclusion that power-efficient SiPM readout solutions can be found, also suitable for Cherenkov light detection with BGO, which opens the door for their implementation in application-specific integrated circuits (ASICs) and systems.