Thermal analysis of electron gun with grid control in pulsed TWT

Summary form only given. The design of electron optical system of electron gun with grid control in pulsed TWT has been completed. During the cathode of grid control electron gun, shadow grid and control grid are radiated, it is necessary to further analyze change of electrode temperature and displacement with the help of CAD technique. Selected material of support piece and integrative heating cathode are analyzed by calculation. These conclusions are gained such as the variation of cathode surface temperature in the range of 10/spl deg/C, the highest temperature of shadow grid to be radiated at 707 /spl deg/C, the temperature of mat edging being lower and the highest surface temperature of control grid at 193/spl deg/C-far below the surface temperature of shadow grid. After cathode heat balance, each electrode will produce expand and displacement so it will result in change of original gap each electrode. By means of CAD analysis, cathode, shadow grid and control grid will produce displacement of 0.06mm ,0.036mm and 0.00875mm respectively when they come under the influence of thermal radiation. So assembling size of electron gun with grid control can be obtained by means of modifying electron optical size. Tests of temperature and displacement of electron gun with grid control are measuring surface temperature each electrode with the aid of micro-optical thermal detector and axial displacement each electrode with the aid of tool microscope. And the assembled electron gun is sealed in glass shell through exhaust. Test data are corresponding with calculating results of CAD.