Modeling crosstalk in silicon photomultipliers

TL;DR

This paper develops and validates analytical models to describe optical crosstalk in silicon photomultipliers, improving understanding of their photon-counting limitations through experimental comparison.

Contribution

It introduces realistic crosstalk models considering pixel neighborhood and dead-time effects, validated with detailed experimental data.

Findings

Models accurately predict crosstalk effects on pulse-height spectra

Experimental data confirms the validity of the models

Provides tools to evaluate excess noise factor due to crosstalk

Abstract

Optical crosstalk seriously limits the photon-counting resolution of silicon photomultipliers. In this work, realistic analytical models to describe the crosstalk effects on the response of these photodetectors are presented and compared with experimental data. The proposed models are based on the hypothesis that each pixel of the array has a finite number of available neighboring pixels to excite via crosstalk. Dead-time effects and geometrical aspects of the propagation of crosstalk between neighbors are taken into account in the models for different neighborhood configurations. Simple expressions to account for crosstalk effects on the pulse-height spectrum as well as to evaluate the excess noise factor due to crosstalk are also given. Dedicated measurements were carried out under both dark-count conditions and pulsed illumination. Moreover, the influence of afterpulsing on the measured pulse-height spectrum was studied, and a measurement of the recovery time of pixels was reported. High-resolution pulse-height spectra were obtained by means of a detailed waveform analysis, and the results have been used to validate our crosstalk models.