Efficient Design Scheme of Superconducting Cavity

For many next-generation high intensity proton accelerator applications including the Spallation Neutron Source (SNS), superconducting (SC) RF provides the technology of choice for the linac. In designing the superconducting cavity, several features, such as peak fields, inter-cell coupling, mechanical stiffness, field flatness, external Q, manufacturability, shunt impedance, higher order mode (HOM), etc., should be considered together. A systematic approach to determine the optimum cavity shape by exploring the entire geometric space of the cavity has been found. The most efficient use of RF energy can be accomplished by adjusting the cell shape. A small region in parameter space satisfying all reasonable design criteria has been found. With this design procedure, choosing the optimum shape is simplified. In this paper, the whole design procedure of this optimisation scheme is explained and applied to the SNS cavity design.