FRIB and Argonne National Laboratory

Lithium charge stripper

FRIB has adopted the liquid lithium charge stripper technology initiated by Argonne National Laboratory (ANL). The initial research and development for this technology was funded directly by the DOE-SC Office of Nuclear Physics to ANL and later continued by FRIB.

The initial work at ANL involved the development of a thick film of liquid lithium to be used as a production target and later a thin film of liquid lithium to be used as charge stripper. During the collaboration between ANL and FRIB, we determined the parameters needed (pressure and nozzle geometry) to obtain a stable, thin lithium film. The development of the final stripper system and the continuously operating electromagnetic pump continue at FRIB.

Half-wave resonator slow tuner

ANL assisted with half-wave resonator (HWR) slow tuner production design for the FRIB cryomodules. Cavities have to be tuned to the designed accelerating frequency. ANL has been designing tuners for the similar cavities, and FRIB was able to leverage ANL’s design experience.

Superconducting resonator processing

ANL, with its expertise in designing and processing superconducting resonators, processed and tested five of the β=0.29 and some of the β=0.53 resonators. Having a second (beyond MSU) resonator processing facility at ANL reduced project risk and leveraged ANL’s expertise and facilities. ANL also mechanically adjusted β=0.29 and β=0.53 resonators to the FRIB design frequencies, employing a specialized technique developed at ANL.

Radio-frequency couplers

ANL has contributed their experience in fabrication of continuous wave radio-frequency (RF) couplers, which transmit the RF power from the amplifier into the normal conducting re-buncher resonator. The FRIB normal conducting at room temperature (RT) in order to stand more robustly the possible beam loss of the ions with un-preferred charges after charge stripping.

Metal brazing

ANL conducted a high-temperature braze on the metals (copper to tungsten) for the water-cooled charge selection slits in folding segment 1 of FRIB’s linear accelerator. ANL’s expertise was needed because maintaining dimensional control of the copper section is difficult at the high temperature, and post-braze machining is required.