Electron beam processing machine with high power electron gun - where cathode wire or strip is stretched between two holders

摘要

Electron gun, esp. for high powder electron beam processing machines, uses a line source obtd. from a heated linear cathode stretched between two cathode holders, and an anode. Between the anode and cathode is a control electrode contg. a gap through which the electrons travel; and one cathode holder can be moved and subjected to the force of a spring. The moving cathode holder is pref. mounted on a slide which can be accurately positioned and the force exerted by the spring pref. decreases with increasing elongation of the cathode wire. A wt. may also be used to stretch the cathode wire, the spring working in opposition to the wt. The cathode wire is pref. vertical, and coolant flows through channels provided in the slide. Used on electron beam machines with an output of several kilowatts, wher accurate beam alignment can still be obtd. after long operating times or after replacing the cathode.