Pulsed vacuum breakdown measurements with a 1-MV generator

Measurements of the breakdown field of vacuum gaps have been made with a 1-MV, 50-ns test stand [1]. The first set of experiments was performed with planar, bare metal electrodes [2]. This geometry had an enhanced anode edge that affected measurements. Here, we report on a new set of measurements using anodes without field enhancement. Diagnostics include current and voltage probes, x-ray detector, x-ray pinhole camera and a fast framing camera. The results of these measurements give new insight into the cause of anode interactions that reduce the breakdown field with large gaps.