MgB2 Coatings for Future SRF Accelerators

Nb is the superconductor of choice for todays SRF accelerators, but the theoretical limits of the material are quickly being reached. An alternative material that could operate at higher temperatures and higher accelerating gradients would provide a reduction in cost for future SRF accelerators. Alameda Applied Sciences Corporation proposes to develop MgB2 coatings on Nb substrates using energetic condensation from a cathodic arc vacuum source. MgB2 has a superconducting transition temperature of ~ 40 K, as opposed to Nb at ~ 9 K, and therefore offers lower surface resistance at temperatures above 2 K. This offers the benefit of moving to cheaper cryogenic systems. MgB2 can also move past the maximum accelerating field of 50 MV/m for Nb.Commercial Applications and Other Benefits: MgB2 coated onto the interior surface of Nb cavities could provide a significant decrease in costs for future SRF accelerators along with being a potential upgrade for existing accelerators, enabling them to reach higher gradients than are presently achievable using Nb.