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

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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.