A Leading Edge Timing and Energy Discriminator

摘要

A single channel timing trigger was constructed using ECL integrated circuits. The discriminator was designed for positron emission tomography, to be placed close to the detectors in the gantry, eliminating the need to transmit fast pulses at low level over long cables. The discriminator generates a timing pulse that indicates the arrival of a photon with an accuracy of a few nanosec, and it examines the energy deposit of the photon, determining if it is above the energy threshold. The time information is extracted from the fast leading edge of the anode signal from a scintillator photomultiplier combination. The anode signal is also filtered through an alternate path. This signal is then used to check the energy criteria.