Probability distribution and noise factor of solid state photomultiplier signals with cross-talk and afterpulsing

Operating principles of Solid State Photomultipliers are based on Geiger mode avalanche breakdown limited by strong negative feedback. This operating mode provides both high gain and ultra-low excess noise of avalanche multiplication resulting in ability to detect single photons. On the other hand high gain is accompanied with cross-talk and afterpulsing processes changing the probability distribution function of output signals and arising specific excess noise. There are many reports regarding its influence on signal distribution and noise, and we suggest that some analytical expressions would be useful. We therefore are presenting a simple model of probability distribution of output signals in the presence of cross-talk and afterpulsing (namely compound Poisson distribution). The model results allow us to calculate excess noise factor of cross-talk and afterpulsing as well as to find simple way to measure its probabilities.