Investigation of copper cathode surface conditioning by subnanosecond vacuum discharges

Abstract

A copper cathode with an effective surface area less than 0.01 mm2 was subjected to several vacu-um arc discharges of submicrosecond duration, which led to significant erosion of the surface and a change in its microrelief. This cathode was then connected to a RADAN pulse generator with a pulse duration of less than 1 ns. Several hundred vacuum discharges were performed on this setup. Before and after the treatment with subnanosecond pulses, the emission characteristics of the sample and the state of its surface were studied. Emission characteristics were studied on a field-emission projector with an automated measuring complex to obtain current-voltage characteristics of the field-emission. The results of these measurements made it possible to estimate the electric field enhancement factor on the sample. The microrelief of the sample surface was studied by scanning electron microscopy. A significant decrease in the field enhancement factor and a decrease in the characteristic dimensions of the surface microrelief elements were shown.