Quantitative study of pulsed X-ray-induced electromagnetic response in coaxial cables

This article aims to quantify the radiation-induced electric responses of coaxial cables while irradiated by a pulsed X-ray flux. First, a precise characterization of the X-ray generator was performed using the 3-D Maxwell and Monte Carlo numerical simulations. These results were used to calculate the currents induced by the X-rays within the cables by using the 3-D Monte Carlo and 2-D transverse electromagnetic numerical codes. A systematic analysis of the responses of several cable references was performed by comparing the experimental and numerical results. This allows for the determination of gaps at the interface between the cable dielectrics and conductors. From these results, a parametric numerical extrapolation at high X-ray fluences was performed. It is shown that the system-generated electromagnetic pulse (SGEMP) responses are governed by photocurrents in gaps below 1011 rad/s, while for greater dose rates, conduction currents in the dielectrics govern the responses. The approach developed in this article is useful for investigating electrical responses of systems subjected to highly ionizing environment, which is of paramount importance for addressing hardening issues.