Repeated γ Irradiation and Thermal Annealing via Built-In Thermo-Electric Coolers of Si Avalanche Photodiodes

When operating in space, on-board Silicon Geiger-Mode Avalanche Photodiodes (GM-APDs) are exposed to radiation damage that result in an increase in dark count rates. Thermal annealing has been found to mitigate the damage, although prior studies have largely focused on annealing following a single session of proton irradiation. This work reports that thermal annealing can be performed simply with the built-in thermo-electric coolers of the GM-APDs. Annealing was also done in 10 min intervals for a clearer view of the recovery curve. Mitigation of damage from repeated γ radiation was observed from the: (1) halving of the increase in dark count rates on average and (2) outperformance of room temperature annealing (25°C) by 33%. Additionally, we show that heavy doses of γ radiation (21 krad) have a probability of causing Random Telegraph Signals in GM-APDs that can be suppressed by lowering the operating temperature.