The RIKEN radio isotope (RI) beam factory requires an intense beam (more than 1 pµA on target) of high charged heavy ions to produce intense RI beam using projectile like fragmentation. In the last decade, the effects of the key parameters (magnetic field configuration, gas pressure etc) on the ECR plasma have been revealed and the performance has been dramatically improved. Such basic studies give us how to optimize the ion source structure. Based on these studies and the modern superconducting technology, we successfully constructed the new superconducting electron cyclotron resonance ion source (SC-ECRIS) which has a flexible magnetic field configuration to enlarge the ECR zone and to optimize the field gradient at ECR point. It has an optimum field strength for the operation of 28 GHz microwave. In the first test experiment, we investigated the effect of ECR zone size, magnetic field configuration, and microwave power on the beam intensity of the highly charged heavy ions with 18 GHz microwaves. In this article, we present the structure of the ion source and these experimental results with 18 GHz microwave in detail.
