The influence of experimental method on the flashover performance of alumina in vacuum

This paper presented some new experimental results observed in our investigation. Based on the experiments, it was found that the different voltage application sequence on the test samples could influence the flashover voltage of the tested samples. Three kinds of voltage application sequences were compared and three kinds of alumina samples were involved in this paper. In general, the flashover voltage is the lowest if the applied voltage started from a lower voltage (-2 kV) at a -2 kV step; the flashover voltage could be the highest if the applied voltage started from -22 kV. The surface charge distributions were observed after the voltage was applied. According to the experimental results, the change of the flashover voltage of the test samples could be attributed to the state of surface charge distribution with different voltage application sequence.