Modeling of single photon avalanche diode array detectors for PET applications

We introduce a novel configurable model of single photon avalanche diodes (SPAD) array photodetectors with intelligent control and active quenching, where individual components can be simulated independently and subsequently linked to provide the overall detector response. The model enables the simulation of performance characteristics including, but not limited to, photon detection efficiency, timing and energy resolution, and can be used to optimize detector performance for specific applications, such as PET. The simulator was implemented in the MATLAB^® environment and consists of multiple configurable and interchangeable modules to model the array geometry, SPAD characteristics and readout electronics based on physics and statistical equations. Monte Carlo simulations are used to model the 511 keV annihilation photon interactions and the optical photon transport in the scintillator, as well as carrier random walk in the silicon. Different methods to extract information from the digital output signal can easily be tested and compared. The simulation results for photon detection efficiency, energy resolution and timing resolution are reported.