  PIXELATED geiger-mode avalanche photodiodes(PPDs), often called silicon
photomultipliers (SiPMs) are emerging as an excellent replacement for
traditional photomultiplier tubes (PMTs) in a variety of detectors, especially
those for subatomic physics experiments, which requires extensive test and
operation procedures in order to achieve uniform responses from all the
devices. In this paper, we show for two PPD brands, Hamamatsu MPPC and SensL
SPM, that the dark noise rate, breakdown voltage and rate of correlated
avalanches can be inferred from the sole measure of dark current as a function
of operating voltage, hence greatly simplifying the characterization procedure.
We introduce a custom electronics system that allows measurement for many
devices concurrently, hence allowing rapid testing and monitoring of many
devices at low cost. Finally, we show that the dark current of Hamamastu
Multi-Pixel Photon Counter (MPPC) is rather independent of temperature at
constant operating voltage, hence the current measure cannot be used to probe
temperature variations. On the other hand, the MPPC current can be used to
monitor light source conditions in DC mode without requiring strong temperature
stability, as long as the integrated source brightness is comparable to the
dark noise rate.
