金属钼、铪栅极材料电子发射问题研究

Study on Electronic Emission of Mo and Hf Grid Material

利用离子束辅助沉积技术在Ba-W阴极表面上分别沉积金属钼膜和铪膜,以模拟栅控行波管中钼栅极和铪栅极表面吸附阴极蒸发物质时的表面状态。研究了这两种栅极表面微观结构和成分的变化,并测试了其表面热电子发射能力和二次电子发射系数。实验结果表明,铪栅极表面吸附的阴极发射物质要远少于钼栅极,用金属铪作栅极材料能有效抑制栅极电子发射。

Mo and Hf were respectively deposited onto the surface of cathode with Ba-W by ion beam assisted deposition to imitate the surface conditions of Mo-grids and Hf-grids when absorbing with electron emission substances in the grid-control TWT. The microstructure and composition of the samples were characterized. The ratios of thermo-electronic emission and secondary electron emission between two grids were compared. The results show that the amount of electron emission substances of the cathode adsorbed on the surface of Hf-grids was rather less than that of the Mo-grids. Hf-grids could effectively suppress the electron emission.