Development of ECR ion sources at RIKEN

The beam intensity of highly charged heavy ions from the electron cyclotron resonance (ECR) ion source has been rapidly increased in the last three decades. Especially, in the last decade, the performance of the ECR ion source was dramatically improved to meet the requirements for the super-heavy element search experiment and the intense ratio isotope beam production. At RIKEN, we constructed several high performance ECR ion sources for those projects. Furthermore, to improve the performance, we studied the effect of the key elements of the ion source on the beam intensity and the plasma. In this article, I describe the brief history of the ion source development and the performance of the ion sources at RIKEN. (author)