This test is used to determine the terrestrial cosmic ray Soft Error Rate (SER) sensitivity of solid state volatile memory arrays and bistable logic elements (e.g. flip-flops) by measuring the error rate while the device is irradiated in a neutron or proton beam of known flux. The results of this accelerated test can be used to estimate the terrestrial cosmic ray induced SER for a given terrestrial cosmic ray radiation environment. This test cannot be used to project alpha-particleinduced SER.