A Method to Analyze Particle Induced Vacuum Breakdown with Obvious Field Emission Current

To reveal vacuum breakdown mechanism is important for insulation enhancement between vacuum gap. In this paper, two already conditioned plane anodes, pure copper, were combined as an electrode pair. The breakdown area and electrode surface of the anodes during and after the conditioning were obtained by breakdown location technology and SEM experiment. Impulse voltage was applied between the combined anode electrode pair. A breakdown waveform with obvious field emission current was captured in the first 20 breakdown tests. The breakdown didn’t happen at the peak value of field emission current. When the field emission current decreased from the peak value, the sudden breakdown occurred. This breakdown phenomenon was captured by two cameras fixed with a right angle, and its position was analyzed and obtained. The breakdown location was not in the breakdown area during anode conditioning but had a distance to it. The electric field around breakdown location was lower than the maximum electric field. After the breakdown, a same impulse voltage was applied again. No breakdown occurred and same field emission current was measured. It revealed that the breakdown was not caused by the former emitters. All these proofs indicated that the breakdown with obvious field emission was caused by particles.