High voltage breakdown studies in electron gun and its damage control

Vacuum breakdown is a very common problem during the operation of any electron gun. Arcing occurs due to high voltage break down of cathode - anode gap. This not only spoils the job, it also causes lot of damage to the electronic component of the system and damage to the emitter. In this work, a detailed study of the cause of the high voltage breakdown in the gun in the electron beam evaporation system, analysis of the electrical parameters of arc discharge inside the electron gun due to high voltage break down and suitable solution to the arc discharge problem has been presented. Power supplies need to be protected against surges arising out of high voltage breakdown. Ferrite beads have been used to suppress the high frequency content of the breakdown signal. High frequency content of the signal in the MHz range can be attenuated to lower range of KHz by use of ferrite bead thereby protecting against high frequency surges. On the other hand during breakdown there is a sudden increase in the current which needs to be limited without interruption in the process. Possible use of superconductor as fault current limiter has been analyzed in this work.