行波管栅控电子枪热形变研究

摘要

行波管栅控电子枪各组件尤其是阴极和栅网的热形变对行波管电子光学性能有着较大的影响.基于有限元分析方法,利用热力场耦合对栅控电子枪热形变问题进行了研究,结果表明:阳极的总形变量最大,最高处达0.28 mm;控制栅网、阴影栅、阴极及部分支撑结构向着阳极方向发生形变,由温升引起的形变不会使控制栅网和阴影栅发生接触或交叉,而阴极形变量较大时,阴极与阴影栅则存在接触的危险,这对电子枪的工作性能有很大的影响,甚至会使阴影栅烧坏.降低电子截获率,适当增加控制栅网和阴影栅的厚度,使用热传导率高、线膨胀系数低的材料,可以减小栅控电子枪各组件的热形变.%The thermal deformation of gridded electron gun in traveling wave tube has much influence on the performance of its electronic optics system and the problem has been investigated by means of the coupling of the thermal field and the mechanics field based on FEM (infinite element method). The results show that the total deformation of the anode is maximum and reaches 0. 28 mm and the deformation of control grid, shadow grid, cathode and some supporting structure is toward the anode. Besides, contact or cross of control grid and shadow grid doesn't occur due to their deformation caused by temperature rise, while the cathode will contact the shadow grid when the deformation of the cathode is larger. The above contact will affect the performance of the gun, even cause the damage to shadow grid. The deformation of the components can be lessened by means of lowering probability of electron interception, thickening control grid and shadow grid properly as well as adopting the material with higher thermal conductivity and lower coefficient of linear expansion.