Feasibility of skewness-based characterization of SiPMs with unresolved spectra

Abstract

Conventional methods of SiPM characterization are mostly based on a resolved spectrum of photoelectron or dark electron detection events which represents a random number of fired SiPM cells. However, such methods are not applicable for unresolved spectra caused, for example, by a low single electron response to noise ratio or a high dark count rate, for example of irradiated SiPMs. This challenge is anticipated in modern developments of radiation-intense facilities like CERN CMS and applications of large-area SiPMs and SiPM arrays with noisy readout like Cherenkov Telescope Array.The method of statistical moments is a well-known technique for the estimation of parameters of a random variable distribution using sample moments of raw data. The first two moments have already been used for estimation of the gain and the number of photoelectrons by the mean and the variance of detected charges relying on a priori knowledge of the Excess Noise Factor of the SiPM or PMT. The third moment or skewness of the measured charge can also be involved to estimate three main SiPM parameters including crosstalk.The skewness-based characterization presumes Generalized Poisson distribution of fired cells which was found to be in good agreement with many experiments. Initial theoretical and experimental evaluations of the skewness method have shown promising results. This study focuses on the feasibility of using such method to characterize the parameters of SiPM with unresolved charge-amplitude spectrum.