Electron Beam Induced Degradation in Electrical Characteristics of Optocoupler

This article describes the electrical degradation in the I-V characteristics and the Current Transfer Ratio (CTR) of commercial optocoupler (4N35) exposed to an electron beam. The devices are exposed to an electron beam of various doses and the I-V characteristics of LED and output characteristics of the phototransistor are measured as a function of accumulated electron dose. The result indicates that 10 MeV electron of 1.5 kGy dose results in considerable degradation in CTR. Further, it appears that the phototransistor of the optocoupler is more susceptible to radiation damage than the LED part and care must be exercised when these devices are used for space applications.