PROGRESS TOWARDS HIGH-INTENSITY HEAVY-ION BEAMS AT RIKEN RIBF

Since the extraction of the first beam in late 2006, the RIKEN Radioactive Isotope Beam Factory (RIBF) has been successfully operating with the aim of accessing the unexplored region on the nuclear chart, far from the stability line. The continuous efforts over these six years have significantly enhanced the performance of the RIBF accelerator complex. Thus far, we have achieved the target intensity of 1,000 pnA for helium and oxygen beams and about half of the target intensity for the calcium beam. The intensity of uranium beams, however, is still to be improved, requiring extensive measures to reach the target intensity. To address this situation, we constructed a 28-GHz superconducting electron cyclotron resonance ion source and a new injector linac. Furthermore, we developed a helium gas charge stripper as an alternative to the standard carbon-foil stripper. This paper presents recent results obtained in the commissioning of the new injector system, the report of the R&D work on the gas charge stripper, and a brief summary of the present performance of the RIBF accelerator complex.