A new charge selector is currently under development at FRIB to intercept unwanted charge states of higher-power 17 - 20 MeV/u stripped heavy ion beams. The charge selector is located in the first bending segment of the FRIB linac, where high dispersion separates charge states to allow for their selection. The design concept is based on rotating graphite cylinders that act as an intermediate heat transfer medium, efficiently absorbing beam power and radiating it to a water-cooled heat exchanger. The power in the beam spot of up to 5 kW and the rms spot width as small as 0.7 mm present significant design challenges. Beyond thermal stress, the proposed design addresses the effects of radiation damage and implantation of the intercepted ions. The challenges of the engineering design associated with high temperatures, thermal expansion, rotation and linear actuation feedthrough into vacuum, as well as radiation shielding and remote handling, will be discussed. A comprehensive exploration of these challenges aims to contribute to the broader field of beam interception technology.

Charge stripping is inherent for high power ion accelerators such as the FRIB LINAC. However, at high power, strippers require motion to prolong the operational life of the stripping media, or by flowing a liquid Lithium film. The charge stripping process introduces energy losses that vary with the actual Lithium film thickness, which can result in observable beam losses along the tuned beamline at high on-target beam power, above ~100 kW, if not adequately mitigated. BPM phase feedback is used in real-time to compensate for these effects, controlling upstream RF cavities in order to maintain a constant beam energy and phase post-stripper, which significantly reduces beam energy fluctuations.