微波管栅发射问题的研究

STUDY ON GRID EMISSION OF MICROWAVE POWER TUBES

利用离子束辅助沉积技术在 Mo栅极上镀上并注入一层 Hf膜,对镀后的样品进行了形貌、结构、成份、膜厚及 Mo、Hf界面分析。将样品进行电子管模拟栅发射试验,栅极温度为 650℃,试验 1000h以上基本无栅发射电流,可以提高栅控管的可靠性和寿命。实验结果表明,阴极中的活性物质Ba蒸发到镀Hf的 Mo栅极表面,Ba,Hf和O_2能形成化合物,从而有效抑制栅极发射电流。

Hf film is coated on the surface of Mo-grids by vacuum ion beam aided deposition technology. The SEM, XRD and RBS analyses are performed on modified Mo-grids. Life-span tests of this modified Mo-grid are carried out by diode experiment. When the temperature of the modified Mo-grids is kept at 650℃, the modified Mo-grids' electron emission can not be detected with microammeter after 1000h life-span. The experimental results show that after the grid is contaminated by electron emission substance Ba of the cathode Hf formed compounds restrain effectively electron emission of grid.