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Coaxial
Energetic Ion Deposition of Superconducting Coatings on Copper RF Cavities for
Mr.
Dr. Mahadevan Krishnan, Business Official, Krishnan@aasc.net
DOE Grant No.
DE-FG02-04ER83896
Amount: $700,000
Radio frequency (RF) cavities are a key component in
particle accelerators for fundamental high-energy physics research and medical
applications. To enhance their
capabilities, niobium-coated superconducting copper cavities have shown promise
for supporting higher electric field gradients when compared to
non-superconducting designs. However, a
satisfactory coating method has not been developed that can deposit
high-quality superconducting films on the insides of these cavities. To date the maximum field gradient that can be
supported in niobium coated copper cavities is about 15 MV/m, which is not adequate
for future accelerator designs. Also,
sheet niobium in use is expensive. This
project will develop a deposition process for coating the inside of copper RF
accelerator cavities with high-quality, superconducting films that will allow
particle accelerators to achieve field gradients greater than 15 MV/m. In Phase I, copper test samples, along with several
sapphire and copper witness plates, were coated with niobium films using the
Coaxial Energetic Deposition process. The
superconducting transition temperature, Tc, and Residual Resistivity Ratio
(RRR) for the films was measured to determine the superconducting properties,
and film properties were assessed.
Finally, a segment of an actual RF accelerator cavity was coated with
niobium. Phase II will develop a Coaxial
Energetic Deposition system that is capable of accommodating and coating 1.3
and 1.5 GHz RF accelerator cavities. In
addition, a production system for transition to Phase III will be developed.
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 them to achieve higher particle energies. Other applications include enhanced protective coatings for coal gasification, olefin manufacturing, and gun barrels for the military.