Nb Coatings for Bellows used in SRF Accelerators

High-current particle accelerators have need for low-impedance bellows connecting accelerating cells and in other areas of the accelerator. Typical techniques to decrease surface impedance are to use shields of superconducting Nb, however, as these shields move they produce particulates that can be detrimental to operation if they find their way into the storage ring. Alameda Applied Sciences Corporation proposes to deposit a superconducting layer of Nb on the inside surface of phosphorus bronze bellows. This superconducting layer should lead to a decrease in the surface resistance at cryogenic temperatures and a decrease in the power consumption of the bellows. Thomas Jefferson National Laboratory will provide analysis facilities for this effort. Commercial Applications and Other Benefits: The production of a particulate-free, low-impedance bellows has application in many of todays high-current particle accelerators, such as accelerator light sources and spallation neutron sources.