Studies of power-flow oscillations in the RITS-6 induction voltage adder accelerator

Summary form only given as follows. Sandia National Laboratories' Radiographic Integrated Test Stand (RITS-6) is a six-stage inductive voltage adder (IVA) accelerator. It is designed to produce maximum currents of 186 kA at 7.8 MV in 70 ns pulses into electron beam diode loads when configured for low-impedance operation. Measurements of current and X-ray dose rate taken from a variety of diode loads have sometimes shown an oscillation typical of a resonant cavity. The oscillations appear intermittently from shot to shot and occur early in the pulse. The source of these oscillations is being studied with fully relativistic particle-in-cell simulations. Results from 3D simulations of the full RITS-6 transmission line, including the induction cavities, are compared to data. Insight into the nature of these oscillations and the modes supported by the geometry are presented.