Simulation Studies of the Effect of SiPM Dark Noise on the Performance of a Highly Granular Crystal ECAL

A proposal for the CEPC ECAL is a highly-granular scintillating crystal design that uses SiPMs to measure physics signals from photons. Radiation damage to the silicon will impair the performance of the calorimeter due to dark noise, which will affect the reconstruction capabilities of the calorimeter system. This paper presents a simulation study assessing the effect of radiation damage of SiPM dark noise on the response from calorimeter to electrons due to changing fluence and temperature. It was observed that dark noise significantly degrades the linearity of response, with up to 45% error in reconstructed energy for a 1 GeV shower at a fluence of $1\times {10}^{10}{\mathrm{c}\mathrm{m}}^{-2}$. The stochastic and noise resolution terms was observed to remain stable, increasing only by 0.2% and 1% respectively in the range $1\times {10}^7-1\times {10}^{10}{\mathrm{c}\mathrm{m}}^{-2}$ fluence. Under the assumption of no irradiation, the influence of dark noise with temperature in the normal operating range of the calorimeter system was estimated to be negligible.