Neutron irradiation effect on SiPMs up to $\Phi_{neq}$ = 5 $\times$ 10$^{14}$ cm$^{-2}$

TL;DR

This study investigates how neutron radiation affects Silicon Photo-Multipliers (SiPMs), introducing a new method to quantify damage effects and optimize their operating conditions for high-radiation environments.

Contribution

The paper presents a novel approach to quantify radiation damage in SiPMs using dark current measurements and pixel occupation probability analysis.

Findings

Neutron irradiation increases dark count rate in SiPMs.

A new method effectively quantifies radiation damage effects.

Operational conditions can be optimized based on pixel occupation probability.

Abstract

Silicon Photo-Multipliers (SiPM) are becoming the photo-detector of choice for increasingly more particle detection applications, from fundamental physics to medical and societal applications. One major consideration for their use at high-luminosity colliders is the radiation damage induced by hadrons, which leads to a dramatic increase of the dark count rate. KETEK SiPMs have been exposed to various fluences of reactor neutrons up to $\Phi_{neq}$ = 5$\times$10$^{14}$ cm$^{-2}$ (1 MeV equivalent neutrons). Results from the I-V, and C-V measurements for temperatures between $-$30$^\circ$C and $+$30$^\circ$C are presented. We propose a new method to quantify the effect of radiation damage on the SiPM performance. Using the measured dark current the single pixel occupation probability as a function of temperature and excess voltage is determined. From the pixel occupation probability the operating conditions for given requirements can be optimized. The method is qualitatively verified using current measurements with the SiPM illuminated by blue LED light.