Development of an automatic procedure for the characterization of silicon photomultipliers

In this paper, we show the analysis software we created for a fast and reliable automatic characterization of a silicon photomultiplier. The program can be used both in dark and under continuous low-level light illumination. It grabs 1ms-long waveforms, each containing many single cell pulses, from an oscilloscope connected to the PC via Ethernet. On-line data analysis is done both on the raw waveform as well as on a filtered (with DLED technique) version in order to facilitate the pulse identification and the extraction of some parameters also in cases of high count rates or cross-talk. The main outcomes of the program are: single-cell signal shape, gain, primary dark count rate, after-pulse probability, direct and delayed cross-talk probability and excess charge factor. It can be used also to determine the actual photo-detection efficiency with the proper hardware set-up.