Feasibility of Higher Electron Gun Voltage and Higher Electric Field by Suppressing Electron Stimulated Desorption from the Anode

Increasing the voltage of electron guns is one of the very important issues to suppress the reduction of electron beam brightness due to space-charge effects. During the conditioning process of a high-voltage electron gun, a threshold exists beyond which inter-electrode vacuum breakdown does not occur. Based on the continuous increase of this threshold through conditioning, a model was established that incorporates ESD (Electron Stimulated Desorption)-induced ions in the vacuum breakdown process. If this model is accurate, it may be possible to prevent breakdowns at higher voltages by suppressing ESD on the anode surface. To suppress ESD, a NEG (Non-Evaporable Getter) film was sputtered onto the electrode surface.