Scintillation detectors constructed with an optimized 2×2 silicon photomultiplier array

Abstract

Silicon photomultipliers (SiPMs) are a good alternative to photomultiplier tubes (PMTs) because their gain and quantum efficiency are comparable to PMTs. However, the largest single-chip SiPM is still less than 1 cm 2 . In order to use SiPMs with scintillators that have reasonable sensitivity, it is necessary to use multiple SiPMs. In this work, scintillation detectors are constructed and tested with a custom 2x2 SiPM array. The layout of the SiPMs and the geometry of the scintillator were determined by performing Geant4 simulations. Cubic NaI, CsI, and CLYC with 18 mm sides have been tested. The output of the scintillation detectors are stabilized over the temperature range between -20 and 50 • C by matching the gain of the SiPMs in the array. The energy resolution for these detectors has been measured as a function of temperature. Furthermore, neutron detection for the CLYC detector was studied in the same temperature range. Using pulse-shape discrimination, neutrons can be cleanly identified without contribution from γ-photons. As a result, these detectors are suitable for deploying in spectroscopic personal radiation detectors (SPRD).

Lithium-Loaded Scintillators Coupled to a Custom-Designed Silicon Photomultiplier Array for Neutron and Gamma-Ray Detection

“…Since the sensitivity of a radiation detector increases with the detector size, it is necessary to assemble SiPMs in an array for larger scintillators. A 2x2 SiPM array has been designed and constructed for coupling with 18 mm cubic scintillators [5]. The gain of the SiPMs in the array are matched in the temperature range between -20 and 50 • C for optimizing the energy resolution.…”