Particle-In-Cell Simulations of Two Cylindrical Reflex Triodes in Parallel

Abstract

Pulsed power diodes that generate bremsstrahlung x-rays are of interest as sources for radiation-matter interaction studies. The cylindrical reflex triode (CRT) is one such diode that is notable for its ability to produce low-endpoint x-ray spectra and its design is favorable to combine multiple CRTs to increase x-ray output, in either series or parallel configurations [1] . CRTs in various configurations are fielded on NRL’s Gamble II generator. This work marks the first particle-in-cell (PIC) simulations of a CRT and will focus on two CRTs in parallel in support of recent Gamble II experiments. The PIC simulations will be used to predict current measurements for the inner and outer triodes as well as report direct voltage measurements near the anode-cathode gap. Radiation production calculations based on the PIC simulation particle outputs will be made to make predictions of the time dependent x-ray production, near field radial dose distribution, and x-ray source distribution. These calculations will be validated against Gamble II experiments. Successful confidence in predictive capability with the model will allow for the development of synthetic x-ray spectra diagnostics.