Response of Boost Converters Under Fission-Spectrum Neutron and Gamma Radiation

Abstract

Radiation testing of microelectronics remains essential for ensuring reliability in environments such as space and nuclear power systems. One critical component found in many systems is the metal oxide semiconductor field-effect transistor (MOSFET). While work has been conducted on early MOSFET designs, there remains a gap in three key areas: testing modern power MOSFETs, collecting live test data, and evaluating components in combined radiation environments. Using modern components ensures that systems currently in use, both public and private, are better protected against radiation damage. Live monitoring allows observation of single-event effects and transient behavior not detectable through post-irradiation analysis. Additionally, conducting experiments in fission-spectrum neutron and gamma environments better replicates real-world conditions. While the literature addresses each of these topics separately, this work combines them by live-testing a boost converter circuit composed of a MAX1932 gate driver and a BSS119N N-type MOSFET under both neutron and gamma radiation. Testing was performed at the Purdue University Reactor Number One (PUR-1) and the Hopewell Co-60 irradiator, evaluating the circuit’s response to gamma total ionizing dose (TID), thermal neutron-induced transients, and environmental temperature. Live monitoring displayed real-time transients, degradation, and recovery behavior. Results indicate gamma radiation plays a dominant role in circuit degradation. However, when considering the dose dependent degradation, the combined radiation environment of PUR-1 induces failure with 34.8% less dose when compared to the Co-60.  Suggesting neutron activation is contributing to secondary gamma dose or ¹⁰B (n,α) reaction damage. While Co-60 testing remains critical, thermal neutron facilities may offer a useful, cost-effective screening method for identifying gamma-sensitive components.