Silicon Photomultipliers in Scintillation Detectors Used For Gamma-Ray Energies Up to 6.1 MeV

The aim of this paper is to study usefulness of SiPM light readout in detection of gamma rays up to 6.1MeV in combination with various scintillators. The reported measurements were made with 3 samples of one type of Hamamatsu TSV (Through Silicon Via technology) MPPC arrays. These 4x4 channel arrays have a 50x50 mu m(2) cell size and 12x12 mm(2) effective active area. All the tests were done in a climatic chamber. The following scintillators were used: CsI(Tl), CeBr3, NaI(Tl). The studies are focused on optimization of the MPPC performance for practical use in detection of high energy gamma rays. The optimization includes selection of the optimum operating voltage in respect to the energy resolution, verification of the dynamic range, linearity and pulse amplitude. The energy spectra for energies between 320keV and 6.1MeV are presented and compared with data acquired with a classic photomultiplier. Such comparison allowed study of nonlinearity of the tested MPPCs, correction of the energy spectra and proper analysis of the energy resolution. The temperature tests show strong breakdown voltage dependence on the temperature change and define requirements for the stabilization method in real life applications.