Simulation of the response of SiPMs; Part I: Without saturation effects

Abstract A Monte Carlo program is presented which simulates the response of SiPMs in the linear regime in which saturation effects can be ignored. Inputs to the program are the mean number and the time distribution of Geiger discharges from photons, as well as the dark-count rate. For every primary Geiger discharge, correlated Geiger discharges due to prompt and delayed cross-talk and after-pulses are simulated, and a table, called Geiger Array, of the amplitudes and times of all Geiger discharges in a specified time window is generated. A number of different physics-based models and statistical treatments for the simulation of correlated Geiger discharges can be selected. The Geiger Arrays for many events together with different options for the pulse shapes of single Geiger discharges can be used to simulate charge spectra, as measured by a current-integrating charge-to-digital converter. In addition, current transients convolved with electronics response functions, as recorded by a digital oscilloscope, and time-difference distributions can be simulated. The program can be used to compare simulation results with different assumptions to experimental data, and thus find out which model is the most appropriate for a given SiPM, optimise the operating conditions and readout for a given application, and test programs for extracting SiPM parameters from experimental data. A Python version of the program is available on request.