First test results of superconducting twin axis cavity for ERL applications

RF superconducting (SRF) cavities with two beam pipes have been proposed in the past for energy recovery linac applications. The relatively complex geometry of those cavities presented a serious challenge for fabrication and surface processing. The main concerns have now been overcome with the fabrication and successful RF testing of a new elliptical twin-axis cavity proposed by Jefferson Lab (JLab) and optimized by the Center for Accelerator Science (CAS) at Old Dominion University (ODU) in the framework of a DoE accelerator stewardship program. The cavity design provides uniform accelerating or decelerating fields for both beams. This paper describes the cavity design, fabrication experience, and the first cold RF test results and explores potential applications especially for JLab's EIC (JLEIC).