Single-event upset effects in optocouplers

Single-event upset is investigated for optocouplers using heavy ions. The threshold LET for optocouplers with internal high-gain amplifiers is very low, causing output transients to occur even when the optocouplers are irradiated with short-range alpha particles. Although previous work with high-energy protons showed that transients were caused by charge collected in the large-area photodetector, transients generated in the high-gain amplifier make a significant contribution to the total cross section when optocouplers are irradiated with heavy ions. The transient pulse width increases with LET, exceeding 400 ns for long-range particles above 7 MeV-cm/sup 2//mg. This is about an order of magnitude greater than the pulse width that occurs when they are irradiated with protons. The ion range must exceed 50 /spl mu/m to characterize the cross section and pulse width in these devices.