Status update of the Charge Stripper Rings project

The RIKEN RI (radioactive isotope) Beam Factory (RIBF) provides the world's most intense heavy ion beams exceeding 345 MeV/u and is the primary facility for in-flight RI beam generation. The RIBF has steadily improved its performance. In particular, the intensity of the uranium beam, which is critical for producing in-flight fission RI beams, has been dramatically increased by a factor of 240 compared to 2008. To further increase the intensity of the uranium beam, a new acceleration scheme using charge stripper rings (CSRs) has been proposed as a cost-effective way to increase charge stripping efficiency. In this paper, we discuss the key design issues of CSR and required upgrades of existing ring cyclotrons with the introduction of CSR and space-charge effects.