Development of a Superconducting RF Multi-Spoke Cavities for Electron Linacs

Future nuclear physics facilities will require high energy, high intensity superconducting radio frequency (SRF) electron linacs for projects such as an electron cooler, an electron-ion collider, and a photofission source. This project will develop multi-spoke structures for electron linacs and compare their performance to standard elliptical accelerating structures. The multi-spoke cavity offers several potential advantages over elliptical cavities: smaller cross section; stronger cell-to-cell coupling; the presence of fundamental and higher-order mode (HOM) couplers, as well as the tuner, in the active cavity region; and more mechanical stability. Phase I would develop the accelerating structure and cryomodule design, based on systems efficiency, beam dynamics simulations, and HOM analysis. Phase II would finalize the cryomodule design and critical aspects of the system, such as the SRF spoke cavities, power coupler, HOM spectrum, and frequency tuners. Commercial Applications and other Benefits as described by the awardee: Future nuclear physics facilities will require high-current electron linear accelerators. The superconducting multi-spoke cavities should serve to accelerate electrons near the speed of light.