Thermal Analysis Study On Electron Gun For Gyrotron Travelling Wave Tube

High power millimeter and sub-millimeter wave technology plays an importantrole in communication, radar, electronic warfare and microwave weapon systems. Highpower gyro-traveling wave tube (Gyro-TWT) is a new millimeter source, it possessesadvantages of high peak power, wide band, and has important application prospect inmilitary and civilian aspect, attracting attention of the world both in theory and inpractice.Thermal stability is an important property of gyrotrons, which can influence itsoperating stability and reliability. The magnetic injection gun (MIG), which is thecrucial component in gyrotrons, operates in high temperature, so its thermal analysisresearch is essential for Gyro-TWT. This dissertation studied the thermal distributionand deformation in MIG, and has made some achievements by changing the cathodestructure.Chapter2shows the background, component and principle of gyrotron. Thedetailed electron gun theory is also introduced in the chapter.Chapter3introduces the theory of calorific included law of conservation of energyand the ways of heat transfer, then introduces the method of finite element and theANSYS software.Chapter4uses the finite element software ANSYS to obtain the temperaturedistribution of the cathode model. In order to maintain the uniformity of surfacetemperature of the cathode emitter, the difference of temperature decreases from18℃to0.9℃by extending the thermal contact area and by decreasing the amount of the heatercoil. Then the change of emission current destiny influenced by different emittertemperature is studied. Finally, this paper researches the heating efficiency of thecathode reducing the heat loss of heat transfer from the slotted angle and slotted numberof metal support shell. The heating power reduces from100W to55W when cathodegets the same temperature.Chapter5analyses the thermal deformation in cathode and the velocity ratio,velocity spread, guide center radius all increase by EGUN code. The thermal and deformation analysis of MIG provide confidence for Gyro-TWT design.