M型阴极寿命特性分析

Life Characteristic Analysis of M-Type Dispenser Cathodes

空间行波管因为其高可靠、高效率、长寿命特性,一直是空间微波功率放大器的首选器件。阴极是其唯一的寿命限制因素,也是可靠性的重要影响因素。本文分析了覆膜阴极的工作机理,并结合寿命实验结果对覆膜阴极的寿命特性进行分析,认为覆膜阴极虽然在寿命过程中,其活性发生持续改变;但工作电流保持稳定不变,只有在寿命末期才会发生明显改变。阴极在寿命过程中,功函数将因为合金化程度、钡的供应、工作温度以及真空气氛的影响发生持续改变。这些因素可通过工艺或设计进行优化,进而获得理想的阴极寿命。

Space traveling wave tube （TWT） has been the preferred device of all microwave power amplifiers because of its high reliability,high efficiency and long life.Consumable cathode is the only life limiting component in a TWT and it also influence the reliability of the device greatly.The working mechanism of M-type dispenser cathode was introduced in this research,and the life characteristic of the cathode was also analyzed considering the life testing results.The analysis indicated that the working current of the cathode,except an obvious change occurred at the end of cathode life,would remain unchanged in most working process although the activity of the cathode changed continuously; while the work function of the cathode would change continuously in working process because of the influence alloying degree,the barium supplying,the working temperature and the vacuum atmosphere.All the factors can be optimized through technical process and design so as to realize an ideal cathode life.