Trigger Performance Simulation of a High Speed ADC-Based TOF-PET Read-Out System

Monte Carlo simulations of a time-of-flight Positron Emission Tomography front end readout system (TOF-PET) are performed to investigate obtainable timing resolution at different ADC sample times using LYSO scintillators. Results from simulations with different combinations of ADC sample times and analog filter time constants are presented. To determine the coincidence resolving time (CRT), a trigger system based on a digital constant fraction zero crossing discriminator (CFD) is investigated. Such a trigger system would be suitable for running real time in a field-programmable gate array (FPGA). It is seen that below a certain sample time, the time resolution is limited by the scintillator and MPPC combination, and not the readout system.