Analysis of a multi-spoke option for the RIA driver linac

Beam dynamics simulations of the proposed Rare Isotope Accelerator (RIA) driver linac have been done. The RIA driver linac is designed to accelerate stable ion beams from proton to uranium to final energies of 400 MeV/u for the heaviest and about 900 MeV/u for the lightest ions with beam powers of 100 to 400 kW. Two stripping sections are used to increase the charge state of heavy ions and minimize the total accelerating voltage required. To achieve the final beam power and to reduce the ion source requirements, multi-charge state beam acceleration is used. Multi-spoke structures in the high-energy part of the driver linac have been proposed as an alternative to the baseline design of 6-cell elliptical structures. A comparative analysis of this alternative is explored including beam dynamics, error constraints, and manufacturing issues.