A normally-distributed crosstalk model for silicon photomultipliers

Optical crosstalk (OCT) in silicon photomultipliers (SiPM) occurs when photon detection in a microcell leads to the production of further photons that are also detected. Various models have been considered to predict experimental data with varying degrees of success. In this paper, we introduce the Normally-Distributed Crosstalk Model (NDCM), where the probability of triggering additional microcells is given by a 2-d normal distribution with a standard deviation of 𝜎: a device-specific parameter representing OCT photon propagation path length in terms of microcell pitch. Monte Carlo (MC) simulations of NDCM are compared to existing models and experimental data from the CHEC-S camera developed for the Cherenkov Telescope Array, which suggests that OCT occurs with a 𝜎 ≈ 5 microcells in this device.