Voltage Breakdown in RF Cavities, DC Vacuum Gaps, and Computer Simulations

Summary form only given. Results from DC breakdown experiments designed to imitate (to some extent) breakdown in microwave resonators will be presented. "Before" and "after" pictures demonstrate the dangers of contaminant particles, and post-breakdown surface analyses show the damage caused by the arc around the field emitter, including the extent of ion bombardment. A simple model can explain the initiation of breakdown at a field emitter around which a monolayer of neutral atoms suddenly desorbs. Computer simulations using OOPIC show in more detail how breakdown might be thus triggered, and confirm the model's predictions of a critical current and gas density necessary for breakdown