Measurements of Natural Radiation Effects in a Low Noise Avalanche Photodiode

Low noise avalanche photodiodes were irradiated to determine their sensitivity to the natural space environment. Radiation effects on important APD parameters were determined by exposure to 1.5 MeV electrons from a Van de Graaff generator and to gamma rays from a Co60 source, both to a total dose of 300 krad (Si). During irradiation, the DC dark current and an associated 1/f noise were found to increase linearly with dose only if bias voltage was applied. A t-x annealing behavior was observed. Radiation damage coefficients, threshold dose rates, and threshold fluences are calculated.