Design and Development of Electron Gun and PPM focusing for Vacuum Power Booster TWT of Broadband MPM

The electron gun and PPM focusing system have been designed and developed for above VPB-TWT. M-type dispenser cathode and electrically isolated BFE has been used. The gun adapter and the anode have been made of Cu-Ni and molybdenum respectively to get desired magnetic flux at the cathode. Compact electron gun assembly has been designed. High voltage analysis, theoretical as well as experimental, is carried out before finalization of assembly in order to meet the desired hold off voltages between different electrodes. Temperature and emission characteristics of the cathode are measured under the loaded conditions