Hardening options for neutron effects - An approach for tactical systems

This paper presents the results of an investigation of quantitative procedures for assessing the probability of failure (PF) of tactical military systems exposed to a neutron radiation environment. All assessments are made with a 90 percent confidence in the determined probability of failure. Two analytical models are developed for predicting the probability of failure of transistor circuits based on small quantity test data or manufacturer´s specifications of gain (6) and gain bandwidth product (fT) . The formulation of these models incorporates the influence of circuit design margins. For circuits where the failure fluence is determined by a single device, a nomograph is presented for calculating PF as a function of fT, initial gain, fluence, and the circuit design margin. Examples are also provided for the use of the models for determining PF via Monte Carlo analyses for circuits including several transistors.