Proceedings of the 19th International Conference on RF Superconductivity
19th International Conference on RF Superconductivity, June 30-July 5th, 2019, Dresden, Germany
Because of superior superconducting properties (Tc ~ 18.3K, Hs h~ 425 mT and Δ ~ 3.1 meV) compared to niobium, Nb₃Sn promise better RF performance (Q₀ and Eacc) and/or higher operating temperature (2 K Vs 4.2 K) for SRF cavities. Nb₃Sn-coated SRF cavities are produced routinely by depositing a few micron-thick Nb₃Sn films on the interior surface of Nb cavities via tin vapor diffusion technique. Early results from Nb₃Sn cavities coated with this technique exhibited precipitous low field Q-slope, also known as Wuppertal slope. Several Nb₃Sn single cell cavities coated at JLab appeared to exhibit similar Q-slope. RF testing of cavities and materials study of witness samples were continuously used to modify the coating protocol. At best condition, we were able to produce Nb₃Sn cavity with Q₀ in excess of ≥ 5×10¹⁰ at 2 K and ≥ 2×1010 at 4 K up the accelerating gradient of ~15 MV/m, without any significant Q-slope. In this presentation, we will discuss recent results from several Nb₃Sn coated single-cell cavities linked with material studies of witness samples, coating process modifications and the possible causative factors to Wuppertal slope.
Original Publication Citation
Pudasaini, U., Eemeev, G., Reece, C.E., Ciovati, G., Parajuli, I.P., Sayeed, Md.N., & Kelley, M.J. Recent results of Nb₃Sn single cell cavities coated at Jefferson Lab. In P. Michel, A. Arnold, V.R.W. Schaa, Proceedings of the 19th International Conference on RF Superconductivity (pp. 65-70) Joint Accelerator Conferences Website. https://doi.org/10.18429/JACoW-SRF2019-MOP018
Pudasaini, U.; Kelley, M. J.; Ciovati, Gianluigi; Eremeev, G.V.; Kelley, M. J.; Reece, C. E.; Parajuli, Ishwari Prasad; Sayeed, Md. Nizam; Michel, Peter (Ed.); Arnold, Andre (Ed.); and Schaa, Volker R.W. (Ed.), "Recent Results From Nb₃Sn Single Cell Cavities Coated at Jefferson Lab" (2019). Physics Faculty Publications. 640.