Measurement of SiPM Dark Currents and Annealing Recovery for Fluences Expected in ePIC Calorimeters at the Electron-Ion Collider

Silicon photomultipliers (SiPMs) will be used to read out all calorimeters in the ePIC experiment at the Electron-Ion Collider (EIC). A thorough characterization of the radiation damage expected for SiPMs under anticipated EIC fluences is essential for accurate simulations, detector design, and effective operational strategies. In this study, we evaluate radiation damage for the specific SiPM models chosen for ePIC across the complete fluence range anticipated at the EIC, 10⁸ to 10¹² 1-MeV neq/cm² per year, depending on the calorimeter location. The SiPMs were irradiated using a 64 MeV proton beam provided by the University of California, Davis 76" Cyclotron. We measured the SiPM dark-current as a function of fluence and bias voltage and investigated the effectiveness of high-temperature annealing to recover radiation damage. These results provide a comprehensive reference for the design, simulation, and operational planning of all ePIC calorimeter systems.