Single Event Upsets in RAMs Induced by Protons at 4.2 GeV and Protons and Neutrons below 100 MeV

Several different types of random-access-memories (RAMs) have been tested for soft upset susceptibility under a variety of different particle bombardments including thermal neutrons, GeV protons, and protons and neutrons below 100 MeV and with few exceptions found to suffer single event upsets. Devices tested included 4K, 16K and 64K dynamic RAMs and 4K NMOS and 256×4 CMOS static RAMs. Mean upset fluences varied from 106 particles/cm2-upset for 64K dynamic RAMs up to no upsets observed for the 256×4 CMOS RAM. No thermal neutron induced upsets are believed to have occurred. GeV protons, simulating primary cosmic rays, caused upsets at levels of 107 particles/cm2-upset.