Neutron irradiation damage on Silicon Photomultipliers and in-situ current annealing studies for the CBM RICH detector

Limited radiation hardness is the primary drawback to implementing Silicon Photomultipliers (SiPMs) in high-luminosity environments, such as the Compressed Baryonic Matter (CBM) experiment. Hadron irradiation generates defects in the silicon lattice of SiPMs, increasing dark current, dark count rate (DCR), and afterpulsing, while degrading photon number resolution. The expected fluence in the photon camera of the Ring Imaging Cherenkov detector of the CBM experiment ranges from 8 × 1 0 9 to 5 × 1 0 10 n eq /cm 2 after two-months of operation at maximum beam energy and intensity. In this work, we evaluated the radiation hardness of three different SiPMs: AFBR-S4N66P024M, S14160-6050HS, and MICROFC-60035. The samples were exposed to neutron fluences ranging from 3 × 1 0 8 to 1 × 1 0 11 n eq /cm 2 . We performed in-situ current annealing (250 °C/30 min) on the samples to recover the photon number resolution and decrease the DCR and dark current.