Performance of SiPMs in the nonlinear region

TL;DR

This paper develops a comprehensive model for the nonlinear response of silicon photomultipliers (SiPMs), accounting for effects like pixel recharging, crosstalk, and afterpulsing, validated through gamma-ray spectrometry experiments.

Contribution

A novel parametrization of SiPM nonlinear response that incorporates complex effects, enabling accurate interpretation of detector signals in gamma-ray spectrometry.

Findings

Model accurately describes SiPM nonlinear behavior

Parameters linked to physical characteristics like pixel recovery time

Improved conversion from signal to energy resolution

Abstract

Silicon photomultipliers present saturation effects as they have a limited number of pixels and work in Geiger mode. Their response to light pulses in the nonlinear region is very complex for two reasons: pixel recharging after an avalanche affects the trigger probability and charge multiplication of subsequent avalanches, and non-trivial effects due to crosstalk and afterpulsing. A parametrization of the nonlinear response of silicon photomultipliers was developed where the above effects were readily accounted for. The model was tested on a setup of gamma-ray spectrometry using different combinations of scintillation crystals and detectors. The model parameters were interpreted in terms of fundamental characteristics of the setup (e.g., lifetime of the scintillation crystal and pixel recovery time). The proper conversion from signal resolution to energy resolution was provided.