In a multimode experimental setup, the surface of the copper cathode was conditioned with high-voltage pulses of subnanosecond duration. The efficiency of the process was evaluated without breaking vacuum conditions using an automated complex for determining the emission properties of the sample. The coefficient of local enhancement of the electric field on the sample surface was estimated based on the current–voltage characteristics of the field electron emission. The microrelief of the sample surface was studied using a scanning electron microscope. The influence of various factors on the effectiveness of the conditioning process was evaluated. Among these factors were sample heating and vacuum conditions. It is shown that increasing the residual gas pressure in the chamber to 10–1 Pa did not affect the characteristic size of the erosion microrelief details of the sample surface and the conditioning efficiency. The use of heating up to 500 K did not have a significant effect on the cathode conditioning, while a further increase in the sample temperature to 700 and 1000 K led to an increase in the probability of breakdown. At the same time, the characteristic diameter of the crater also increased, but its relative vertical size decreased and the rim of the solidified melt was smoothed. This effect can be used to improve the conditioning efficiency of electrodes, but further study of its applicability range is required.
Zemskov et al. (Mon,) studied this question.