Design study of a superconducting linac for RIA

The proposed Rare Isotope Accelerator Facility (RIA) requires a heavy-ion driver linac capable of accelerating uranium to 400 MeV/u with the beam powers of 100 to 400 kW. The beam power requirement will be met for very heavy ions by simultaneous acceleration of multiple charge states because of ion source limitations. To minimize the number of accelerating structures, two charge stripping stations have been proposed for nuclei heavier than Kr. The intensity loss due to multiple stripping is minimal by the multiple charge acceleration. However, the technical challenges and concomitant risks of the stripping stations for the proposed beam powers are significant particularly at the lowest energy. As a consequence, an alternative layout with only one stripping station at a point about twice the energy of the lowest energy of the two-station scenario is proposed. This scheme removes one stripping system, but increases the installed accelerator requirement by about 10%. The beam dynamics of the driver linac has been studied using a newly written single particle tracking program as well as other extant programs