Cost-Effective, High-Performance, High-Purity Niobium Superconducting Radio Frequency Cavities

78163S Superconducting radio frequency (RF) accelerating cavities provide high continuous wave operating fields while offering higher beam quality and reduced beam-cavity interaction for high-energy physics research. An efficient and cost-effective fabrication methodology for the large-scale production of superconducting RF cavities is needed for the rapidly expanding number of superconducting high-energy accelerator projects. This project will develop an efficient, cost-effective fabrication methodology to produce superconducting RF cavities via chemical vapor deposition (CVD). The methodology will eliminate, or substantially reduce, the need for electron beam welding, along with many other costly, time-consuming, and often performance-killing fabrication steps currently used in the production of superconducting RF cavities. Phase I will focus on developing a fabrication method for producing high-purity CVD niobium with net-mirror-shaped low surface roughness (Rq<30 nms) suitable for use in optimally performing solid niobium superconducting RF cavities. The efficacy of these efforts will be determined through mechanical testing and metallographic examination. Cost predictions for the potential large-scale production of solid niobium RF cavities via the newly developed fabrication techniques also will be developed. Phase II will include the production and testing of at least two high-purity solid niobium superconducting RF cavities using the new technology. Commercial Applications and Other Benefits as described by the awardee: The methodology should have application to all particle accelerators, the tool of choice for fields as diverse as ion implantation, high-energy physics, surface analysis, medical treatment, waste sterilization, airport security, food preservation, spallation neutron physics, and coherent light research.