SWELL and Other SRF Split Cavity Development

An innovative superconducting cavity topology has been recently proposed at CERN. It integrates longitudinal waveguide slots crossing perpendicularly the RF surface to damp transverse higher order modes. The RF current lines of the fundamental mode run along the slots, inducing no perturbation of the accelerating mode. Thanks to this approach, the cavity can be built by sectors, which is well appropriate to precise manufacturing techniques. This configuration allows direct access to the RF surface, thus facilitating the surface preparation and thin film deposition process in the case of cavities based on Nb/Cu technology. This paper covers the latest development of a 600 MHz slotted elliptical cavity called SWELL, which has been proposed as an alternative option for the FCC-ee RF system as well as the prototyping of a simplified SWELL version of a single cell 1.3 GHz elliptical cavity. The development of a new type of 6 GHz split resonator is also on-going at Lancaster University. This cavity is made of two halves and is dedicated to superconducting thin film characterization. An overview of this new development will be given.