2021 年 17 巻 4 号 p. 247-259
The electron cyclotron resonance (ECR) ion source is one of the best ion sources to use as an external ion source of the accelerator complex for the radio-active isotope beam factory. The performance of the ECR ion source has been rapidly improved in the last three decades. Especially, in the last decade, it was dramatically improved to meet the requirements for the super-heavy element search experiment and the intense radio-active isotope beam production. At RIKEN, superconducting ECR ion sources with 28 GHz microwaves were constructed to produce intense metallic ions beams (U, V etc.) for these purposes. In this article, I describe the status of the ECR ion source at RIKEN and the effect of main parameters of the ion source (magnetic field distributions, microwave frequency and power, gas pressure etc.) on the plasma and beam intensity of highly charged heavy ions. Based on these results, I briefly present how to produce more intense beam of heavy ions with the ECR ions source.