Studies of MPPC detectors down to cryogenic temperatures

This work reports on the behavior of the Multi-Pixel Photon Counter (MPPC) detectors produced by Hamamatsu HPK in a temperature range from +55 °C down to −175 °C. Devices of 1×1 mm2 and 3×3 mm2 total area and 50×50 μm2 μcell size have been studied. Electrical parameters such as breakdown voltage, gain, capacitance, pulse shape, quenching resistance and dark count rate were measured and some of them showed important temperature variation. Besides this temperature dependence, it is shown that MPPC detectors can operate with a stable gain independent of T if the overvoltage is kept constant. Moreover, at a given temperature, the device of 3×3 mm2 (production year 2011) presents seven times less dark rate/mm2 with respect to the one of 1×1 mm2 (production year 2007), showing an important technological improvement implemented by HPK during four year׳s time interval.