Weld technology reliability analysis of cathode in vacuum tube

Influence of weld technology on reliability and life to cathode in vacuum tube was studied by requests of microwave tube. The quality of weld technology quite affects the emission capability of cathode. The mode of weld quite affects thermal efficiency of cathode in vacuum tube. Thermal efficiency of cathode can increase availably by changing the weld technology on the heat transfer path. Thermal analysis and optimization design of cathode module for vacuum tube was carried out with the FEM in order to obtain required cathode temperature with lower heat power. The weld mode quite affects the cathode heat power, for example, the cathode heat power can reduce 28.6% with 8+8 laser spot welding. We have also built the life test system of TWT's electron gun structure of 8+8 laser spot welding, using this life test system, up to 30 years life of cathode is forecasted.