Characterization of Silicon Photomultipliers for the DarkSide-20k Experiment

DarkSide-20k is a dark matter search experiment using a tonne-scale dual-phase liquid argon TPC that will be capable of confirming a positive observation or of further extending the exclusion limits well beyond any current or presently planned experiment. In order to instrument DarkSide-20k, the Collaboration conducted an intensive program aimed at the development of Silicon Photomultiplier (SiPM) technology to detect the liquid argon scintillation light. The SiPM-based photon detectors have many advantages over the traditional photomultiplier tubes, which are crucial for achieving an unprecedented sensitivity to the WIMP dark matter. In this talk, we will present the complete characterization of the SiPMs produced by Fondazione Bruno Kessler and optimized for cryogenic operation, which will be used in the experiment. Various features, such as dark rate, gain, and correlated noises, were measured in several dedicated setups at 87 K. Additionally, we will present one of the first cryogenic measurements of the Photon Detection Efficiency (PDE) of these devices in the 350-600 nm wavelength range.