Study on Production Mechanism of Multiply-Charged Heavy Ions in ECR Ion Source

本研究的目的是通过设计、制造、调试和使用一个用于东京大学核研究所SF回旋加速器的6.4 GHz微波功率源的ECR离子源（SF-ECR）来研究ECR离子源中多电荷重离子的产生机制。SF-ECR于1988年开始生产梁。此外，一个紧凑的ECR源（HiECR）进行了研究，在6.4 GHz和14.25 GHz的微波频率。[1]6.4GHz微波频率SF-ECR离子源的研究（a）SF-ECR离子源的研究采用一个封闭ECR区（模式I）。结果表明，该模式对气体离子到Ar离子都有很好的性能。(b)SF-ECR研究了两个封闭的ECR区（模式II）。发现该模式具有与模式I相似的性能。(c)然而，具有不同的磁场分布的两种模式的性能之间的比较表明，模式II似乎有更大的潜力比模式I在更高的电荷状态下产生更高的离子电流。(d)SF-ECR安装在SF回旋加速器上，并作为整个系统进行性能测试。由于结果令人满意，SF-ECR开始常规运行。[2]在6.4 GHz微波频率下对HiECR离子源进行的研究结果表明，这种紧凑型离子源也具有与SF-ECR相当的良好性能。与SF-ECR相比，它对低电荷态的离子产生更高的电流，但对高电荷态的离子产生更低的电流。[3]HiECR在14.25GHz微波频率下的性能研究在实验台上安装了一个14.25GHz微波功率源系统。HiECR的性能研究就是在这个频率上开始的。

The aim of this research has been to investigate production mechanism of multiply-charged heavy ions in ECR ion source through designing, manufacturing, tuning, and using an ECR ion source(SF-ECR) with a 6.4-GHz microwave power source for the SF cyclotron of the Institute for Nuclear Study, University of Tokyo. SF-ECR started to produce beams in 1988. In addition, a compact ECR source(HiECR) was studied at 6.4-GHz and 14.25-GHz microwave frequencies.[1] Studies carried out on SF-ECR ion source at 6.4-GHz microwave frequency (a) SF-ECR was studied with one closed ECR zone (mode I). It was found that this mode has excellent performance for gassous ions up to Ar. (b) SF-ECR was studied with two closed ECR zones (mode II). It was found that this mode has similar performance to that of mode I. (c) Comparison between the performances of the two modes which have different magnetic field distributions, however, showed that the mode II seems to have larger potentiality than mode I for producing higher current of ions in higher-charge states. (d) SF-ECR was installed at the SF cyclotron and performance was tested as a whole system. Since it showed satisfactory results, SF-ECR started routine operation.[2] Studies carried out on HiECR ion source at 6.4-GHz microwave frequency This compact source turned out to have also a good performance comparable to SF-ECR. It produced higher current for ions in lower-charge states than SF-ECR, but lower current for ions in higher-charge states.[3] Studies on performance of HiECR at 14.25-GHz microwave frequency A 14.25-GHz microwave power-source system was installed at a test bench. Investigation on performance of HiECR started at this frequency.