Recent performance of Japanese electron cyclotron resonance ion sources (invited)

Since the first Japanese electron cyclotron resonance ion sources (ECRISs) constructed, several tens of ECRISs have been used in many Japanese laboratories. Even if we choose the ECRIS which has an operational frequency higher than 6 GHz, 20 ECRISs are used for various purposes. At the end of the 1990s, three 18 GHz ECRISs were successfully operated and produced an intense beam of highly charged ions at JAERI Takasaki, NIRS and RIKEN; i.e., 1 mA of Ar8+ and 300 e mu A of Ar11+. Various improvements to increase the beam intensity have been done, concerning the aluminum cylinder, biased electrode method. In the last decade, over 50 kinds of metallic ions have been produced from ECRIS using various methods. In 1998, we started to construct new superconducting ECRIS and to perform new experiments of mass spectrometry using ECRIS. This article will review the ECRIS progress and discuss the mechanism to increase the beam intensity of highly charged ions. We also describe a future plan and its new application in Japan. (C) 2000 American Institute of Physics. [S0034-6748(00)50802-8].