Design of a gridded electron gun for traveling-wave tubes: An EGUN case study

A design procedure of a 0.7 muPerv electron gun, with grid and shadow grid, under space charge-limited flow to be used in traveling-wave-tube (TWT) is presented. The EGUN was used to determine the self-consistent electric fields for the electron beam and, as a result, it was obtained a current/perveance growth as the grid voltage increased and the cathode-to-anode spacing decreased. This behavior was observed when grid voltages and cathode-to-anode spacing were varied from 0-600 V and 0.8-1.2 mm, respectively.