用于静电加速器的高频离子源及其引出特性

根据离子束生物工程的需要，设计和研制了一台用于静电加速器的小型高频离子源。针对使用环境从理论上确定了离子源的结构和尺寸。通过实验调试取得了引出束流与引出电压、聚焦电压以及放电气压之间的变化特性曲线，测定了引出束流的束径包络，对束流的不稳定性进行了分析,在设计中采取了有效的措施抑制束流不稳定性。结果表明，离子源的最佳工作条件为引出电压1 600V~1 800V，放电气压在（4~8）×10-4Pa范围，此时离子源可引出最大束流30μA。束流大小及其稳定性均达到预期要求。

RF-driven ion source used in an electrostatic accelerator and its extracting properties

A rf-driven ion source has been developed for the ion beam bioengineering. As used in an electrostatic accelerator, the ion source was specially designed considering with the structure, weight and the power supplies. The size of the extracting electrode was calculated in detail. The extracting beam characteristics of the ion source depending on extracting voltage, focusing voltage and gas pressure were obtained by experiments. The variation of the beam radius along the axis was measured. Factors producing the beam instability were generally discussed, and effective techniques were used to reduce the beam instability. Experimental results showed that the extracting characteristics matched the theoretical expectation well. the maximum beam current was obtained when the extracting voltage was