  The dark count rate of a multipixel photon counter (MPPC) was reduced to less
than 0.2 cps by cooling the counter to 78.5 K. Characteristics of the MPPC
other than the dark count rate were also detemined at 78.5 K and 295 K. The
photodetection efficiency and the timing jitter at 78.5 K were comparable to
those at 295 K. The MPPC had a count rate of up to 50 MHz at 78.5 K and above
100 MHz at 295 K. Detailed measurements were performed for detemining the
afterpulse probability.
