Characterisation of silicon photomultipliers in a dilution refrigerator down to 9.4 mK towards a cryogenic cosmic-ray muon veto system

TL;DR

This study characterizes a silicon photomultiplier operating at near-absolute zero temperatures inside a dilution refrigerator, aiming to develop a cryogenic cosmic-ray muon veto system for low-background experiments.

Contribution

It provides the first detailed characterization of a cryogenic SiPM and demonstrates its potential for detecting cosmic-ray muons within a dilution refrigerator environment.

Findings

Successfully operated SiPM at 9.4 mK environment.

Measured single photon response, gain, and noise characteristics.

Demonstrated proof-of-concept detection of high-energy events.

Abstract

We report the characterisation of a FBK NUV-HD-cryo silicon photomultiplier (SiPM) sensor operated in a 9.4 $\pm$ 0.2 mK environment inside a dilution refrigerator, towards the development of a cryogenic cosmic ray muon veto system to be operated internal to a dilution refrigerator required for low background experiments such as the QUEST-DMC dark matter search experiment. We characterise the single photon response and the gain (the charge produced per detected photon), the dark count noise rate, and correlated noise contributions as a function of operating voltage. This paper also reports first proof-of-concept measurements of using a SiPM coupled to scintillator internal to a dilution refrigerator, towards detecting high-energy events consistent with candidate cosmic-ray muon signals.