Development of rotating beryllium disk stripper

High-intensity uranium (U) ion beams are successfully provided at the RIKEN RI Beam Factory. We have attempted to extend the lifetime of the charge stripper as the U-beam intensity has increased. An attempt to enlarge the irradiated area using a rotating large carbon disk (C-disk) failed in 2006–2007 because no commercially available C-disk with 0.085 mm thickness met our requirements. In 2012, we tested a beryllium (Be) disk (0.1-mm-thick, diameter = 120 mm) as an alternative to the C-disk. The Be disk proved to be an adequate substitute, and has been successfully used during beam-time operation.