A multimethod approach to quantifying atmospheric neutron beam modulation in electronic systems

Modern electronic systems are typically highly integrated, structurally complex, and multilayered. During their operational lifecycle, some of these systems inevitably encounter neutron environments, which can lead to their functional failures or equipment damage. To validate their resilience against neutron irradiation, accelerated neutron irradiation tests are generally required. In this study, a multimethod approach was developed to quantify the modulation of the atmospheric neutron beam. Specifically, the neutron modulation induced by multilayered printed circuit boards (PCBs) was measured at the Atmospheric Neutron Irradiation Spectrometer (ANIS) for the first time. Bismuth (Bi) activation foils, a time-of-flight diamond detector, and an static random access memory (SRAM) monitor were used, respectively. The neutron flux decreases by more than 25% for six-layer PCBs across most of the neutron energy range. Monte Carlo simulations were also conducted and compared with the experimental data. This study can help researchers calibrate the experimental results when conducting accelerated neutron irradiation tests at ANIS.