Characterizing silicon photomultipliers for a next generation neutron detector

A nucleus of protons and neutrons resides at the center of all atoms. It is an on-going effort to build a coherent understanding of how protons and neutrons organize into the more than 3300 nuclei discovered to date, especially those with a large neutron-proton asymmetry. Studies of neutron-unbound nuclei make use of invariant mass spectroscopy (IMS) to measure systems that decay via neutron emission as soon as they’re created. These measurements reveal undiscovered systems and further our understanding of the atomic nucleus by providing important benchmarks for theoretical models.

A key component of these types of IMS studies is the neutron detection system. The Modular Neutron Array (MoNA) collaboration is currently investigating a Next Generation Neutron detector design that aims to improve the position resolution for neutron measurements and consequently the resolution of the invariant mass reconstruction. Specifically, we are investigating the applicability of silicon photomultipliers (SiPM) coupled to scintillator tiles. SiPMs are sensors that can detect low light signals down to the single photon level, and a finalized next generation neutron detector array will incorporate just over 8000 SiPMs. This necessitates an automated process for determining SiPM bias settings and calibration. This presentation will share preliminary results from SiPM response calibration and two methods for breakdown voltage measurement for a batch of SiPMs assembled for the detector development project.