Single Event Upsets in NMOS Microprocessors

Three advanced 16-bit NMOS microprocessors have been observed to suffer single event upset at a rate varying between one upset for every 8 × 1010 to one for every 2 × 1012 n/cm2-upset for cyclotron-produced neutrons with an average energy of 14 MeV. These rates are expected to vary, probably upward, with different types of programs. The errors are inferred to occur in memory-like components of the microprocessors. Many of the errors caused the microcomputer to cease normal operations. This is the first direct experimental verification of logic upsets in microprocessors from neutrons.