Abstract: In order to enhance the transport of cesium vapor from the cesium nozzle to the plasma electrode in a radio-frequency driven negative hydrogen ion source, the cesium feeding process on a radio-frequency driven negative hydrogen ion source was experimentally investigated. In the experiment, elemental cesium was applied as the source of cesium vapor, and cesium gun was fed into the negative hydrogen ion source. A spectrometer was used to monitor the intensity of the cesium emission spectrum (852 nm) near the plasma electrode to assess the cesium vapor content. In the experiment, the emission spectrum intensities of cesium near the plasma electrode are compared for the diffusion chamber of the negative ion source under good cooling and the active heating conditions. The results show that the active heating of the diffusion chamber of the negative ion source can greatly enhance the transport of cesium. By comparing the effect of two different types of cesium nozzles (straight and side nozzles), it is found that the straight nozzles are difficult to produce uniformly distributed cesium deposition on the plasma electrode, but the combination of the side nozzles and the active heating of the diffusion chamber can make the cesium deposition on the surface of the plasma electrode more uniform.

Key words: Radio frequency negative ion source, Surface generation, Cesium injection, Temperature control

摘要： 为了在射频驱动的负氢离子源中增强铯蒸气从铯喷嘴到等离子体电极的输运，对射频驱动的负氢离子源上的馈铯过程开展了实验研究。实验中使用单质铯作为铯蒸气来源，使用铯枪馈入至负氢离子源中。使用了光谱仪对等离子体电极附近的铯发射光谱(852 nm)强度进行监测以评估铯蒸气含量。实验中对比了负离子源的扩散腔在良好冷却条件下和充分主动加热条件下等离子体电极附近铯的发射光谱的强度，结果说明对负离子源的扩散腔进行主动加热可以大幅度增强铯的输运。对 2 种不同形式的铯喷嘴(直喷嘴和侧向喷嘴)产生的效果进行对比，发现直喷嘴难以在等离子体电极上产生沉积均匀分布的铯，而结合侧向喷嘴和扩散腔主动加热 2 种方式，可以使等离子体电极表面的铯沉积更为均匀。

关键词: 射频负离子源, 表面产生, 铯注入, 温度控制