Multi-q beam studies at FRIB: simulations and measurements

The Facility for Rare Isotope Beams (FRIB) linear accelerator is capable of simultaneously transporting and accelerating multiple-charge-state heavy-ion beams. Accurate transverse and longitudinal matching of these beams is a challenging problem, particularly in achromatic bending segments of the linac. To solve it, we employ both macroparticle tracking and linear optics codes. The simulation models are being developed, cross-checked, and validated by beam measurements. The studies are focused on the beam size, envelope matching, charge state separation, and the response of the beam position. The results of the studies with the 16.5 MeV/u five-charge-state uranium beam will be presented.