大面积环状LaB<sub>6</sub>阴极

大面积环状LaB₆阴极

摘要: 介绍了一种用于管状电子束发射的大面积LaB6阴极电子源，其阴极发射面积为115 mm2，LaB6发射体用钼作基底，在LaB6与钼之间用耐高温的碳化物粘合剂填充以防止LaB6与钼发生反应。采用电子束轰击的方式加热LaB6发射体，当阴极温度为1 873 K时，加热功率为173 W，直流发射电流密度达到40 A/cm2。与用石墨加热LaB6发射体相比，该电子源加热功率降低了66%。阴极在室温下反复暴露于大气后其发射性能稳定。

Abstract: In this paper we reported a ring-shaped LaB6 cathode with a large emission area of 115 mm2. The direct emission current density of the LaB6 was more than 40 A/cm2 when the temperature of LaB6 was 1 873 K. The heating power for the LaB6 cathode was only 173 W when the temperature of LaB6 cathode was as high as 1 873 K, in which an electron beam source was employed as the heater. The heating power decreased 66%, compared to that when the conversional graphite acted as the heater. It presented excellent emitting performance even after the cathode was exposed to the air many times.