强流电子束二极管陶瓷真空界面

High electric field ceramic-vacuum interface for high-current electron beam diodes

从绝缘和机械强度两方面优化设计了一种应用于强流电子束二极管的陶瓷真空界面。首先,依据真空沿面闪络机理及其影响因素,针对外径220mm的陶瓷板,应用ANSYS静电场模拟,通过对阴极电极形状和阳极外壳尺寸的调整,使得陶瓷沿面电场和阴、阳极三结合点场强均得到了有效控制。模拟结果显示:陶瓷沿面电场分布均匀,阴、阳极三结合点场强小于30kV/cm,电场线与陶瓷表面所成角度基本保持在45°;其次,针对陶瓷与电极的约束结构,通过静力和瞬态冲击分析,确定了该陶瓷界面可承受的最大静压和冲击波最大峰压分别为4.8MPa和60MPa;最后,在脉宽200ns的脉冲功率驱动源上进行了实验研究,陶瓷真空界面平均绝缘场强达到44kV/cm,二极管运行稳定,机械性能可靠,实验结果与理论设计相符。

For a high-current electron beam diode,in order to make reliable vacuum sealing,a ceramic vacuum interface was developed,following the compact and transportable demand:a novel radial insulation structure was designed and the hydrodynamic loading of the ceramic component was considered.For the insulation design,according to the theories of vacuum flashover and the rules for radial insulators,the electrostatic field along the ceramic surface was simulated by ANSYS package.By optimizing the outline of the anode and reshaping the shielding rings,the electric fields were well distributed and the field around the cathode triple junction was effectively controlled.Furthermore,the mechanic properties of the ceramic component were analyzed.Calculations show that the static and dynamic load for the ceramic interface is 4.8MPa and 60MPa,respectively.Finally,a vacuum diode with the ceramic interface was tested on a 200ns high-voltage pulser,and the results show that the interface can work stably with the hold-off field of 44kV/cm.