Mass testing of SiPMs for the CMVD at IICHEP

A Cosmic Muon Veto Detector (CMVD) is being built around the mini-Iron Calorime-ter (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 em-bedded 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 effi-ciency 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 anal-ysed characteristics of about 3.5k SiPMs.