On the characterisation of SiPMs from pulse-height spectra

TL;DR

This paper develops comprehensive methods to analyze SiPM pulse-height spectra in dark and illuminated conditions, enabling detailed characterization of device parameters and aiding in optimization and calibration for large-scale applications.

Contribution

It introduces a unified model describing the entire pulse-height spectrum of SiPMs, including background regions, for detailed parameter extraction and device characterization.

Findings

Accurate determination of SiPM parameters such as gain, dark-count rate, and cross-talk probabilities.

Demonstration of the model on a KETEK SiPM with comparison to other methods.

Proposal of a calibration method suitable for large-scale SiPM applications.

Abstract

Methods are developed, which use the pulse-height spectra of SiPMs measured in the dark and illuminated by pulsed light, to determine the pulse shape, the dark-count rate, the gain, the average number of photons initiating a Geiger discharge, the probabilities for prompt cross-talk and after-pulses, as well as the electronics noise and the gain fluctuations between and in pixels. The entire pulse-height spectra, including the background regions in-between the peaks corresponding to different number of Geiger discharges, are described by single functions. As a demonstration, the model is used to characterise a KETEK SiPM with 4382 pixels of 15 \mu m x 15 \mu m area for voltages between 2.5 and 8 V above the breakdown voltage at 20{\deg}C. The results are compared to other methods of characterising SiPMs. Finally, examples are given, how the complete description of the pulse-eight spectra can be used to optimise the operating voltage of SiPMs, and a method for an in-situ calibration and monitoring of SiPMs, suited for large-scale applications, is proposed.