Characterization of CMOS SPADs for future RICH Detectors

TL;DR

This paper characterizes CMOS SPADs designed for future RICH detectors, focusing on their performance under high radiation and cryogenic conditions to meet the demands of upgraded particle physics experiments.

Contribution

It provides experimental data on the radiation hardness and cryogenic operation of CMOS SPADs in 55 nm and 110 nm technologies for RICH detector applications.

Findings

Dark count rate remains manageable after high neutron irradiation.

Cryogenic cooling significantly reduces dark counts in irradiated SPADs.

CMOS SPADs show promise for radiation-hard, high-performance photon detection.

Abstract

In the planned or considered upgrades of LHCb, ALICE and Belle II experiments, the Ring imaging Cherenkov (RICH) detectors will have to be improved in order to function at increased beam interaction density. The photodetectors used in future RICH detector will have to provide high granularity, single photon sensitivity and excellent timing, while being exposed to a couple of 10$^{13}$ 1-MeV neutron equivalent/cm$^2$ of background irradiation during total experiment run time. The spadRICH project is developing a CMOS single-photon avalanche diode (SPAD) based photodetector specifically optimized for the application of the planned RICH detectors, which includes neutron radiation hardness and cryogenic operation. In this work we present recent experimental characterization studies of existing SPADs produced in 55 nm BCD and 110 nm CMOS image sensor technologies. Main results include dark count rate (DCR) measurements with SPADs irradiated up to 10$^{12}$ 1-MeV neutron equivalent/cm$^2$ and cooled down to liquid nitrogen temperature.