Enhanced Plasma Throughput for Superconducting Niobium Thin Film Deposition in RF Accelerator Cavities

Radio frequency (RF) cavities, key components in particle accelerators for fundamental high energy physics research, increasingly utilize superconducting technology to achieve higher accelerating field gradients. Traditionally, superconducting RF cavities are made of niobium, which, although expensive and difficult to fabricate, is able to be formed into large mechanical structures. Recently, interest has been growing in replacing niobium cavities with copper cavities coated with thin superconducting niobium films. Coaxial energetic deposition (CED), a cathodic arc process, has been shown to be well-suited for this application, provided that macro-particles can be separated from the deposition ions and sufficiently high deposition rates can be achieved. Therefore, this project will further develop the CED process for coating the inside of copper RF accelerator cavities with high-quality niobium films. In Phase I, an active macro-particle filter will be developed and the process repetition rate will be increased, both to increase the process deposition rate. Commercial Applications and other Benefits as described by the awardee: The superconducting thin film coatings for accelerator cavities should reduce the development and operating costs of particle accelerators, and allow existing accelerators to achieve higher particle energies. The technology also should lead to enhanced coatings for other applications, for example, protective coatings for coal gasification, olefin manufacturing, and gun barrels for the military.