An electron gun design for a C-band TWT

In this paper a design procedure of a 9kV, 0.45A, with a beam waist of 1.5 mm electron gun, without control grid, operating under the space-charge limited condition, to be used in a C-Band Traveling-Wave Tube (TWT), is presented. During the design, three electron gun geometric parameters were varied, namely: the cathode-anode distance, the anode height and the focusing electrode angle, in order to study the electron beam behavior. To cut the electron beam current, a negative voltage was applied on the focusing electrode. It was verified that a 2.5kV biasing negative voltage in the focusing electrode, decreased the electric current from 0.45 A to 1.2mA. All gun simulations were done using the EGUN code.