Optical design, simulation and verification of indirectly heated solid cathode electron gun

Electron beam offers unique advantages as a heat source for melting of refractory metals. It provides contamination free homogeneous melting with precise heat control on the melt target. Industries require these electron beam systems to operate for longer duration. Indirectly heated solid cathode guns can operate for longer durations. This paper reports the design of back gun which is used to heat the source (solid cathode) for further emission of beam. This beam is used for melting the material. The design objective of the back gun is to obtain the solid cathode temperature to 2800K. The design constrains are to minimize the high voltage discharges in the gun, solid cathode should emit 2.5A at 40kV and reduce beam losses in the beam transport. The optimization of grid voltage with its experimental verification is presented in the paper. (author)