Residual Gas Adsorption on Electrode Surfaces in Vacuum

Abstract

The pre-breakdown currents of a vacuum gap both just after spark conditioning of the electrodes and after exposure to a vacuum were measured in a vacuum of 3×10-5 Pa using a switching impulse voltage. It was found that the exposure reduced the field emission current and that this reduction became greater with the exposure time. The reduction in the field emission current is considered to be the result of an increase in the work function due to adsorption of residual gases on the electrode surfaces. Current pulses were also observed to appear on the pre-breakdown currents measured after exposures of longer than 5 minutes.