The current mode Time-over-Threshold ASIC for a MPPC module in a TOF-PET system

Silicon photo-multipliers (SiPMs) and multipixel photon counters (MPPCs) are solid-state silicon photosensors operating in the Geiger mode. These photosensors possess high gain and high timing performance. In the field of medicine, these photosensors are employed in positron emission tomography (PET), and their features are used for time-of-flight PET (TOF-PET). We designed a 48 channels front-end application specific integration circuit (ASIC) for MPPCs of the TOF-PET system. The circuit in the ASIC consists of a current processing method for realizing a high speed performance. At the output stage, a current mode Time-over-Threshold (ToT) circuit was implemented. The current mode ToT converts the current signal from the MPPC into a digital pulse signal and supplies the timing and energy information. We performed experiments for timing resolution measurement, spectra measurement, and coincidence measurement. (c) 2017 Published by Elsevier B.V.