WEC2I2
FRIB, East Lansing, Michigan, USA
ANL, Lemont, Illinois, USA
The charge stripping of a primary beam in heavy ion accelerators is an essential process to achieve a high beam energy at targets. The Facility for Rare Isotope Beams (FRIB), which aims at achieving an ultimate primary beam power of 400 kW, has charge strippers where the primary beam energy reaches 17-20 MeV/u in the driver linac. Because of the unprecedented intensity of heavy ion beams to achieve the 400 kW power, ultra-high thermal load and radiation damage to the charge stripping material will make it practically useless if a solid is used. To overcome these challenges, FRIB chose liquid lithium as a revolutionary stripper material, which is a superior heat remover and free from radiation damage. FRIB¿s liquid lithium charge stripper (LLCS) produces a liquid lithium thin film flowing at 60 m/s, which gives a relatively flat film with a thickness of 10-20 ¿m (0.5-1.0 mg/cm2). We also have a carbon foil charge stripper (CCS), which is a carbon foil that rotates and moves vertically to spread thermal and radiation damage. We have demonstrated that both the CCS and LLCS can support 5-kW-at-target Xe primary beam operations. We will discuss their performance in this paper.
