The 2025 International Workshop on the High Energy Circular Electron Positron Collider

A proposed highly-granular crystal ECAL for CEPC uses SiPMs to detect photon signals. Radiation-induced SiPM dark noise degrades calorimeter performance. A simulation study was performed to estimate the expected degradation in linearity of response and resolution due radiation damage to SiPMs. Simulations show dark noise causes up to 45% error in reconstructed energy for a 1 GeV electron shower at $1\times10^{10}$ $\mathrm{cm^{-2}}$ fluence. Stochastic and noise resolution terms increase minimally by 0.2% and 1% respectively over the range $1\times10^{7}-1\times10^{10}$ $\mathrm{cm^{-2}}$ fluence. Without irradiation, dark noise from temperature variations within normal operating conditions is negligible.