铯束管超高真空维持特性研究

The Research of Ultra-high Vacuum Maintenance of the Cesium Beam Tube

铯束管超高真空长期维持特性是铯原子钟的关键技术指标之一,真空度会影响铯原子钟的性能指标及寿命。材料表面放气率是影响铯束管真空度的主要因素。在铯束管封装过程中,必须针对不同材料制定相应的真空除气工艺来减小材料的放气率,并在铯束管内安装溅射离子泵来维持真空。本文通过理论分析,得出了铯束管内的工作压力,并测试了溅射离子泵的各项性能指标、真空度与铯炉工作温度之间的关系、铯束管的真空维持特性等,研究结果为磁选态铯束管研制及测试提供了参考。

The ultra-high vacuum maintenance characteristic affects the specifications and the life of the cesium beam tube(CBT),which is one of the key technical of the cesium atomic clock.During the CBT vacuum encapsulation,specify the appropriate degassing process for different materials to reduce the outgassing rate,and rely on sputtering ion pump to keep the CBT on ultra-high vacuum environment.The operation pressure was calculated,and the technical specifications of the pump,the variation of oven temperature with pressure and the performance of vacuum maintenance of CBT were experimental evaluated.The results provide the reference for the testing and development of the magnetic state-selecting CBT.