Double upsets from glancing collisions: a simple model verified with flight data (SRAM)

A simple model for the geometry for lateral strikes by heavy ions has been developed. Rates for double upsets in a 93L422 RAM (random access memory) have been calculated with the geometry model and with an integral approach for calculating the upset rates when there is a distribution of charge deposition for upset. The method of calculating upset rates has been verified with flight data on single events from two geostationary satellites, and the geometry model has been verified with double upset events observed on one of them. The single rates agree with observations to within a factor of two, and the fraction of double rates is in close agreement with the flight data. Events were observed when there was a minimum of solar activity so that the contribution from proton upsets was negligible. >