Templated Niobium Films for SRF Cavities

The Department of Energy is interested in the development of techniques to create a layer of niobium on the interior of a copper elliptical accelerator cavity, such as by energetic ion deposition, so that the resulting 700-1500 MHz structures have Q0>8 x 109 at 2K and so that overall fabrication costs are reduced relative to using sheet niobium. In this project, energetic ion deposition will be used to produce niobium films with near-bulk properties on copper substrates. The film structure will be controlled through a heteroepitaxial templating process and evaluated by measurement of superconducting radio-frequency properties in a TE011 cavity. Optimum processing conditions will be identified for scale-up of the process, leading to the energetic deposition of niobium thin films on the interior of copper elliptical cavities. Commercial Applications and other Benefits as described by the awardee: The method should provide a significant reduction in material, fabrication, and operation costs over bulk, niobium metal cavities. The availability of lower cost accelerators would have widespread application in the nuclear physics, medical, and materials science markets.