FRIB, East Lansing, Michigan, USA
MSU, East Lansing, Michigan, USA
ANL, Lemont, Illinois, USA
The Facility for Rare Isotope Beams (FRIB) at Michi-gan State University is a 400 kW heavy ion linear accel-erator. Heavy ion accelerators normally include a charge stripper to remove electrons from the beams to increase the charge state of the beams thus to increase the energy gain. Thin carbon foils have been the traditional charge stripper but are limited in power density by the damage they suffer (sublimation and radiation damage) and con-sequently short lifetimes. Because of the high beam pow-er, FRIB had decided to use a liquid lithium charge strip-per (LLCS), a self-replenishing medium that is free from radiation damage. FRIB recently commissioned a LLCS with heavy ion beams (36Ar, 48Ca, 124Xe and 238U beams at energies of 17-20 MeV/u). Since there had been no exper-imental data available of charge stripping characteristics of liquid lithium, this was the first demonstration of charge stripping by a LLCS. The beams were successfully stripped by the LLCS with slightly lower charge states than the carbon foils of the same mass thickness. The LLCS started serving the charge stripper for FRIB user operations with a backup rotating carbon foil charge stripper. FRIB has become the world’s first accelerator that utilizes a LLCS.
