Charge Stripper Ring for RIKEN RI Beam Factory

The use of charge strippers is almost inevitable for the efficient acceleration of particularly heavy ions such as uranium in heavy-ion accelerator complexes. At the RIKEN RI beam factory (RIBF), the total charge stripping efficiency of two strippers, He gas and rotating graphite sheet disk strippers, used for uranium acceleration is less than 5%, which creates a serious bottleneck for potential intensity upgrades in the near future. We have proposed using charge stripper rings (CSRs) as a cost-effective way to enhance the charge stripping efficiency in a multi-stage accelerator complex involving cyclotrons such as the RIBF. In this paper, we present some calculation results on the key design issues of a CSR.