Influence of electrode shape and electron beam treatment on conditioning in vacuum gap breakdown

The authors have been studying the conditioning effect characteristic of dielectric breakdowns in a vacuum. Tests were carried out to see the conditioning effect at nonuniform field gaps and the effect of electron beam treatment. The results of the tests with stainless steel electrodes showed that the smaller the cathode electrode area, the sooner the conditioning effect at nonuniform field gaps ended and as with uniform field gaps, the electrode area was also important. The conditioning effect can be ended sooner by allowing a melted layer, having a finer structure, to form on the electrode surface by treating it with an electron beam. This effect is produced probably because the electron beam treatment suppresses prebreakdown currents and removes impurities from the electrode surface and inside it.