Linear voltage recovery after a breakdown in a pulsed dc system

Abstract

Breakdowns (BDs) may occur in high-voltage applications even in ultrahigh vacuum conditions. Previously, we showed that it is important to pay attention to the post-BD voltage recovery in order to limit the appearance of secondary BDs associated with the primary ones. This can improve the overall efficiency of the high-voltage device. In this study, we focus on the optimization of the linear post-BD voltage recovery, with the principle aim of alleviating the problem of the secondary BDs. We investigate voltage recovery scenarios with different starting voltages and slopes of linear voltage increase by using a pulsed dc system. We find that a higher number of pulses during the voltage recovery produces fewer secondary BDs and a lower overall BD rate. Lowering the number of pulses led to more dramatic voltage recovery resulting in higher BD rates. A steeper voltage increase rate led to a more localized occurrence of the secondary BDs near the end of the voltage recovery period. It was also found that the peak BD probability is regularly observed around 1 s after the end of the ramping period and that its value decreases exponentially with the amount of energy put into the system during the ramping. The value also decays exponentially with a half-life of (1.4±0.3) ms if the voltage only increased between the voltage recovery steps.