A Cold Cathode Electron Gun Using Convex Carbon Nanotube Emitter

The electron beam quality of an electron gun is the key factor for the performance of vacuum electron devices. It is reported here that a convex carbon nanotube (CNT) emitter cathode is realized, improving the focus and laminar flow of the electron beam for a cold cathode gun. A mechanical polishing treatment was used to fabricate a convex shaped emitter of the cold cathode from vertically aligned CNTs, and it showed that the convex shaped emitter could effectively overcome the edge emission effect and improve the distribution uniformity. Also, the convex CNT cold cathode was utilized to fabricate a coaxial electron gun, and it presented that the beam spot of the gun is regular and uniform. Compared with the planar CNT emitter cathode, the convex emitter cathode demonstrated better uniformity and compatibility on the quality control of the electron beam. The present results indicate a viable route for improving the electron beam quality of nano-materials’ cold cathode gun.