General Upper Bound On Single-event Upset Rate

A technique of predicting an upper bound on the rate at which single-event upsets due to ionizing radiation occur in semiconducting memory cells is described. The upper bound on the upset rate, which depends on the high-energy particle environment in earth orbit and accelerator cross section data, is given by the product of an upper bound linear energy transfer spectrum I
_∞
and the mean cross section of the memory cell. Plots of the spectrum I
_∞
are given for low inclination and polar orbits. An alternative expression for the "exact" upset rate is also presented. Both methods rely only on experimentally obtained cross section data and are valid for sensitive bit regions having arbitrary shape.