Design Calculations for High-Space-Charge Beam-to-RF Conversion

Summary form only given. Recent advances and implementations of new "cut-cell" algorithms now permits very accurate 2nd-order geometry representation in modeling tools which have the required self-consistent treatment of space-charge and mode fields, necessary for design of the high-space-charge beam-to-RF conversion subcomponents. This development significantly reduces design and modeling effort, while simultaneously improving precision. We demonstrate this new capability in the VORPAL software framework for devices which convert bunched beam kinetic energy to RF energy, including output cavity components of klystrons and IOT\´s in accelerator upgrade programs. In addition, we test the ability of this new modeling capability to accurately predict the energy recovery process in a superconducting rf cavity. In this latter design calculation, we require an order-or-magnitude greater precision than typically required for similar calculations of RF sources. In all situations, we also require accurate information of the induced particle spread and velocity shears on exit from the cavities. Time permitting, we also investigate the feasibility of the modeling capability to be applied to other complex-geometry aspects of RF sources, such as the gun and collectors.