Abstract
A digital silicon photomultiplier (dSiPM) consists of an array of single photon avalanche diodes (SPADs) operating in Geiger-mode. Each SPAD is connected to a dedicated CMOS quenching and digitization circuit. One type of dSiPM is the Digital Photon Counter (DPC) manufactured by Philips Digital Photon Counting (PDPC). Due to the digital architecture of the device, a DPC can be adapted and optimized for different applications through a set of adjustable acquisition parameters. The influence of these parameters must be well understood for the correct use of the sensor. In particular, for applications involving low light intensity, such as in scintillation detectors, it is essential to carefully set all the parameters related to triggering and validation in order to discriminate between noise and true events. The triggering and validation processes in a DPC intrinsically are of a probabilistic nature since their fully digital implementations are based on configurable logic interconnections between groups of SPADs. In this study we develop an analytical model that relates the probability of triggering and validation to the number of fired SPADs in a given event, for some of the available trigger and validation schemes. The model is shown to accurately predict experimental data acquired on a PDPC DPC3200-22-44.