Characterization and development of NUV SiPMs for INFN optical modules for the SCT Medium Size Telescope proposed for the CTA Observatory

Abstract

The third generation of Near Ultraviolet High Density (NUV-HD3) Silicon Photomultipliers (SiPMs) produced by Fondazione Bruno Kessler in collaboration with Istituto Nazionale di Fisica Nucleare (INFN) have been tested and characterized in INFN laboratories. Arrays of 16 pixels have been assembled to equip the focal plane of the prototype Schwarzschild-Couder Medium Size Telescope (pSCT) proposed for the Cherenkov Telescope Array Observatory. Each camera module is composed by 4 matrices of 16-pixel optical units coupled with TARGET-7 ASIC front-end electronics for signal amplification and digitization. A total of 9 modules have been successfully integrated on the pSCT camera and are currently taking data. In this contribution we provide a summary of the performances of the HD3 technology as measured in the INFN laboratories. We also report on the laboratory tests performed on the assembled optical units, showing their performances and homogeneity in terms of gain, signal-to-noise ratio and dark count rate.