Low Temperature Proton Irradiation and Annealing Effects on Accumulation CCDs

Radiation testing and annealing of silicon-based detectors at room temperature are well established in the literature, whereas data on irradiation and subsequent annealing at low temperatures remain limited. This study examines proton irradiation effects at −30°C on accumulation charge-coupled devices (ACCDs), up to a displacement damage dose (DDD) of 337.16 TeV/g and a total ionizing dose (TID) of 13.59 krad(Si), followed by extended low-temperature annealing over 6.5 months. Key parameters such as dark current, activation energies, random telegraph signal (RTS) and annealing factors are explored and compared between ACCDs that have been irradiated and annealed both at room temperature and under flight-representative low-temperature conditions. Since silicon detectors in space are typically operated at low temperatures to reduce dark current and improve performance, this study highlights that defect formation and behaviour differ between room-temperature and low-temperature irradiation and annealing, demonstrating that on-ground room-temperature testing may not fully capture defect dynamics relevant to space environments and stressing the significant role of biasing during low-temperature irradiation.