Design of low current density elliptical sheet beam gun

Abstract

Low current density sheet beam electron gun is very useful for compact planar travelling wave tube (TWT). In this paper, a planner low current density elliptical sheet beam electron gun is presented, and the structure parameters of this electron gun are optimized to get low current density for the application of planar TWTs. The gun has an elliptical cathode, critical bearing on the laminarity of beam. With optimizing the structure, cathode, focusing and anode, parameters, the gun is achieved a sheet beam of 110A/cm2 at an operating beam voltage of 9.5kv with the final beam cross-section at 800μm × 60μm. The simulation results show this gun can produce a good focused laminar sheet beam.