Speaker
Description
Superconducting RF cavities fabricated using MgB$_2$-coated Cu possess the potential to operate at higher temperatures and magnetic fields than SRF cavities made from Nb and Nb compounds. We report the ongoing efforts to develop MgB$_2$-coated Cu Superconducting RF cavities through the Hybrid Physical-Chemical Vapor Deposition technique. Microns-thick MgB$_2$ films coated on mockup 1.3 GHz TESLA-type Cu cavities with small witness samples attached on the inner wall exhibiting sharp superconducting transitions at around 37 K uniformly as measured by AC susceptibility. Rutherford backscattering spectrometry and Energy-dispersive X-ray spectroscopy were employed to analyze the depth profile of the elementary constituents in the MgB$_2$ films. RF properties of the MgB$_2$ films on Cu were investigated using the dielectric resonator technique, showing the RF surface resistance comparable to Nb at 10.8 GHz and 6 K. We are nearing the completion of coating and testing a prototype Cu SRF cavity.