The technical advances enabling the Facility for Rare Isotope Beams

The Facility for Rare Isotope Beams (FRIB), a major nuclear physics facility for research with fast, stopped, and reaccelerated rare isotope beams, was successfully commissioned and has been in operation for the past two years. Since this facility is the first in the world to deliver 400 kW of any ion species, including the heaviest uranium in continuous wave mode, several key technologies were successfully developed and implemented, such as full-scale cryogenics and superconducting radiofrequency resonator system, large acceptance fragment separator, stripping of heavy ions with a thin liquid lithium film, and simultaneous acceleration of multiple-charge-state heavy ion beams. The FRIB team adopted an incremental approach toward the ultimate goal of energy and power of primary beams by safe operation and avoiding any possible damage to the machine. Following this strategy, FRIB routinely delivers 10 kW primary beams on target, a factor of 10 above used at the beginning of user operation. Every incremental step in energy and power of primary beams allows us to gain valuable experience in the facility's safe operation and provides directions for further improvements. Single-slice rotating targets rated up to 50 kW and a static beam dump rated for ~20 kW are employed to absorb the primary beam power. The ultimate goal of 400 kW on the target requires further testing of a multi-slice rotating target and water-filled rotating beam dump.