Radiation effects in a photo-coupler with high-energy electrons and γ-rays and recovery by current annealing

Abstract

The radiation damage of a photo‐coupler, composed of GaAs LED and Si phototransistor, is studied by irradiation with 7 MeV electrons from a linac and γ‐rays from 60Co. The current transfer ratio (GTE) is measured at room temperature and 77 K. The CTR decreases rapidly over total dose of about 1012 electrons/cm2 for electron irradiation and 103 Gy (Si) for γ‐ray irradiation. Changes of the CTR by irradiation, measured at 77 K, are smaller than those at room temperature. The CTR of the photo‐coupler, irradiated with 2.6 × 104 G‐y (Si), could be recovered to about 50% of the preirradiation value due to current annealing by applying the forward current of 100 mA to the LED in the photo‐coupler for about 100 min.