Innovative Modular, Multiple Power Levels, 325 MHz Spokes Cavities Power Couplers

In order to increase proton energy up to 8 GeV in a driver linear accelerator, particles must be accelerated through various stages and three different power levels (25kW, 100 kW, and 210kw). Unfortunately, no power coupler element for these cavities has ever been produced using U.S. industrial capabilities. This project will develop innovative modular, multiple power level, 325 MHz spoke cavities power couplers. Phase I optimized and defined parameters for the 325 Mhz RF power couplers. Multipacting calculations were made to determine the RF parameters and to investigate the thermal characteristics of the coupler designs. Phase II will involve further optimization and finalization of the RF and thermal characteristics; detailed engineering drawings with emphasis on the use of cost saving features and approaches; fabrication of a prototype coupler for operation at 25-210 kW peak power, in order to meet all specifications of the proposed Proton Driver Linac at Fermi National Laboratory (FNL); and high power testing of the coupler(s) at FNL to verify performance. Commercial Applications and other Benefits as described by the awardee: The modular component design should significantly reduce the fabrication costs for the 110 power couplers required for the Fermilab Proton Driver, by reducing the parts fabrication costs and the number of brazing fixtures needed. The modular universal design could be the model for any future cost saving applications, where several coupler power levels are required for many DOE accelerator projects and industrial applications.