A New Quarter-Wave Coaxial Coupler For1.3 GHZ Superconducting Cavity

The current design for the RF couplers for the cavity of the International Linear Collider (ILC) introduces unacceptable emittance growth in the beam. This project will investigate two new couplers designed to mitigate the emittance growth problem by preserving the axial symmetry of the cavity fields. Phase I will involve (1) optimization of the design of the coaxial coupler units; (2) a complete analysis of the ILC structure with the new coupler units, in order to confirm its electrodynamic properties; (3) a conceptual mechanical design of the coupler units; and (4) the selection of an optimal configuration for the accelerating cavity and couplers. Commercial Applications and other Benefits as described by the awardee: The new coupler design should successfully achieve the requirements of the ILC cavities, which require a coupler with no back kick in order to preserve the beam emittance and hence the luminosity of the collider.