Study of MPPC damage induced by neutrons

This paper presents the results of neutron irradiation of two types of Multi-Pixel Photon Counter (MPPC). The measurements were taken at the National Centre for Nuclear Research (NCBJ), Poland and the Joint Institute for Nuclear Research (JINR), Russia. Two types of neutron source were used: PuBe with a continuous energy spectrum up to 11 MeV, and mono-energetic 4.8 MeV neutrons produced in a (d,d) reaction. For both sources, fluence in the range of 1010 n/mm2 was achieved. A series of MPPC tests were performed after each irradiation. The changes in MPPC properties, such as current-voltage (I-V) characteristics, breakdown voltage and energy resolution of 662 keV from the 137Cs gamma line for a Gd3Al2.6Ga2.4O12:Ce (1%) scintillator as a function of neutron fluence are presented.