UV Pre-Ionized Rail-Gap Switch for Stacked Blumlein Pulse Generators

Stacked blumlein pulse generators comprised of parallel-plate transmission lines are potentially a useful pulse-power architecture for high-gradient, compact, electron-beam accelerators and other applications. Such pulse generators require a low-inductance, fast (<5ns) switch per stage to erect the stack and produce the desired output pulse. We are developing a rail-gap switch tightly integrated with the stack for this application. We employ ultraviolet light (UV) to pre-ionize the switch, which facilitates prompt, low-jitter, and potentially multi channel operation. A novel aspect of our switch is that the source of the UV is a conventional Xenon flashlamp. This allows variation of the switch pressure and gas without affecting the flashlamp operation. We can operate our switch in either triggered or self-breaking mode. Here we present initial results of a two-stage, stacked blumlein operating in self-break mode. We compare the switch performance to gas-switch scaling laws with respect to resistive-phase risetime and trigger delay as a function of gas density, gap-length, and gap-voltage.