A Sipm-Based Detection Module For 2 '' Labr3:Ce Readout For Nuclear Physics Applications

We present a SiPM-based gamma-ray detection module, which allows to read large LaBr3:Ce cylindrical crystals (diameter > 1 ''), typically adopted in nuclear physics experiments, with spectroscopic performances similar to those achievable with PMTs. High-Density SiPM technology for Near UltraViolet and blue light detection (NUV-HD, Fondazione Bruno Kessler, Italy) were used. These SiPMs show high Photo Detection Efficiency (PDE = 45% at 380 nm) and low Dark Count Rate (DCR < 100 kHz/mm(2)). The photodetector prototype has a modular structure based on an array of 5 x 6 SiPMs, each one having an active area of 6 x 6 mm(2) and 30 mu m microcells. This array was used for 1 '' scintillator readout and it was assembled in 2 x 2 planar format for the 2 '' scintillator readout. The spectroscopic measurements presented in this work were performed with 2 '' x 2 '' LaBr3:Ce irradiated with Co-57, Ba-133, Cs-137 and Co-60 calibration sources. An energy resolution of 3.19 +/- 0.01% was achieved at 662 keV with 2 '' LaBr3:Ce. The same crystal was tested with a Super Bialkali PMT (Hamamatsu R6233-100) showing a similar energy resolution of 3.07 +/- 0.03% at 662 keV. Therefore, these results support the equivalence between SiPM and PMT for high-resolution spectroscopy.