Nb3Sn thin films grown using energetic condensation for SRF applications

Conference · Mon Oct 01 04:00:00 EDT 2012

OSTI ID:1968158

James, C. ^[1]; Bures, B. ^[1]; Zhao, X. ^[2]; Valente-Feliciano, A. ^[2]; Spradlin, J. ^[2]; Phillips, L. ^[2]; Reece, C. ^[2]; Krishnan, M. ^[1]

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1. Alameda Applied Sciences Corporation, San Leandro, CA, USA
2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

The traditional method used to coat thin films of Nb3Sn onto SRF cavities has been to start with a Nb cavity and dip it into molten Sn. At high temperatures (>1100 °C), the Sn diffuses into the Nb to create a stoichiometrically correct film1,2 that offers superconducting properties. Here we describe a lower-temperature process that uses two separate plasmas of Nb and Sn to fire 50-150eV ions of Nb and Sn at a substrate that is heated to <400 °C. The non-equilibrium energetic condensation of Nb and Sn ions via subplantation3 creates a high crystal quality film of Nb3Sn. The stoichiometry of this film is controlled by adjusting the currents to the two separate cathodes that in turn controls the ion fluxes to the substrate. EDX, Tc, RRR and other measurements show that this method enables growth of superconducting films even on relatively low temperature substrates. This approach might offer a path to creating higher temperature Cu SRF cavities of the future that might reduce materials and cryogenics costs. 1 G. Arnolds-Mayer, Proc. SRF2, Geneva, Switzerland, pp. 643-666, 1984 2 Sam Posen, Matthias Liepe, Yi Xie, N. Valles, Proceedings of Thin Films Workshop, Padua Italy, October 2010 3 M. Krishnan et al., Superconductor Science and Technology, vol. 24, no. 11, p. 115002, Nov. 2011

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1968158
• Report Number(s): JLAB-ACC-12-1499; DOE/OR/23177-2508
• Country of Publication: United States
• Language: English