2×2 MPPC arrays in gamma spectrometry with CsI(Tl), LSO:Ce(Ca), LaBr3, BGO

The aim of this work is characterization of MPPC arrays with active area of 6×6 mm in gamma-ray spectrometry with four scintillators CsI(Tl), LSO:Ce(Ca), LaBr₃ and BGO. The chosen scintillators have significantly different decay times of a scintillation pulse and different wavelength of emission peaks. It allowed study of the influence of MPPC effective dead time on a device response and calculation of a Photon Detection Efficiency (PDE) of MPPC. The measurements covered : a selection of the optimum operating voltage, a verification of the linearity range for a given decay time of the crystals, a verification of the excess noise factor for the optimal voltage and calculation of the PDE of MPPC. Measurements of energy resolution and non-proportionality obtained with the MPPC arrays and CsI(Tl) or BGO were compared to the similar measurements performed with XP2020Q PMT.