Charge-stripping system for [sup.238]U ion beam with recirculating He gas

Recent developments in a charge-stripping system employing high-flow rate He gas circulation (~ 200 L/min) for [sup.238][U.sup.35+] beams injected at 10.8 MeV/u are reported. He gas is confined in a target section and is separated from a vacuum duct using five-stage differentially-pumped sections. To minimize the gas leakage rate via beam apertures, a high-performance differential pumping was required. To avoid huge gas consumption, a clean gas recycling with high-flow rate was simultaneously required. To realize these, we developed multi-stage mechanical booster pump array. The recycling rate of He gas was achieved as more than 99%. The system performance has been checked with the present maximum beam current up to 13 eµA(~ 1 kW beam power). Keywords Charge stripper * Uranium ion * Helium gas * Low-Z gas