Front-end processing electronics for a PET tomograph based on BGO-avalanche photodiode detectors

Summary form only given, as follows. The front-end analog and digital signal processing electronics for the Sherbrooke animal PET (positron emission tomography) tomograph, based on BGO-avalanche photodiode detectors, is discussed. The system is implemented with high-density dual-side surface mount printed circuit boards mounted directly behind the detector arrays in the tomograph, and FASTBUS format boards housed in external cabinets. The signals from each detector are processed using fast/slow channels for timing/energy validation. Constant fraction discrimination is used to generate the timing pulses. Gated integration and analog-to-digital conversion of the slow signals allow energy discrimination to be performed digitally. The control parameters for delays and discriminator thresholds are all software-programmable through digital-to-analog converters or on-board memory registers, and their adjustment can be performed automatically by a computer.<>