Xiyuan She’s research while affiliated with Northwest Institute Of Textile Science And Technology and other places

Vacuum surface flashover switch is a promising technique scheme of high repetitive frequency fast-closing switch applied to dielectric wall accelerator. In this paper, the switch is experimentally investigated, and a nanosecond pulse with 2.02-ns effective rise time is obtained. For a cylinder-fused quartz dielectric, the breakdown field of the switch is near 55 kV/cm, and the value for the frustoconical-shaped dielectric exceeds 120 kV/cm with a lifetime up to 69,000 discharges. The repetitive frequency ability of the switch is better than 100 Hz, and the breakdown voltage increases slightly with higher frequency.

The parameter for indicating the characteristics of the surface flashover voltage in vacuum is studied. Experiment results show that, compared with another conditioning method, the flashover voltages of ablative materials obtained by the multi-round stepped increasing voltage method (termed MRSIVM) are increased by 100-200%. This flashover voltage is defined as the intrinsic-like surface flashover voltage (termed ILSFV). The mechanism and significance of ILSFV are studied. After the testing process of MRSIVM, dielectric surface achieves a relatively stable state and the influence of random factors is reduced. The amplitude of ILSFV is higher and the scatter of that is smaller. In addition, the ILSFV stands for an attainable insulation level. So it is more appropriate to represent the surface flashover characteristic of the insulating material by ILSFV.