Mass testing of SiPMs for the CMVD at IICHEP

TL;DR

This paper presents a comprehensive testing system for evaluating approximately 3,500 SiPMs used in the Cosmic Muon Veto Detector at the India-based Neutrino Observatory, focusing on noise, gain, and overvoltage characteristics.

Contribution

It introduces a novel LED-based testing system for mass characterization of SiPMs, ensuring they meet the stringent efficiency and fake veto rate requirements.

Findings

Successful characterization of 3,500 SiPMs

Identification of optimal overvoltage settings for each SiPM

Data supporting the selection of SiPMs for the CMVD

Abstract

A Cosmic Muon Veto Detector (CMVD) is being built around the mini-Iron Calorimeter (mini-ICAL) detector at the transit campus of the India based Neutrino Observatory, Madurai. The CMV detector will be made using extruded plastic scintillators with embedded wavelength shifting (WLS) fibres which propagate re-emitted photons of longer wavelengths to silicon photo-multipliers (SiPMs). The SiPMs detect these scintillation photons, producing electronic signals. The design goal for the cosmic muon veto efficiency of the CMV is $>$99.99\% and fake veto rate less than 10$^{-5}$. A testing system was developed, using an LED driver, to measure the noise rate and gain of each SiPM, and thus determine its overvoltage ($V_{ov}$). This paper describes the test results and the analysed characteristics of about 3.5k SiPMs.