Analysis of Nb3Sn surface layers for superconducting radio frequency cavity applications
- Argonne National Lab. (ANL), Argonne, IL (United States); Illinois Inst. of Technology, Chicago, IL (United States)
- Cornell Lab. for Accelerator-Based Sciences and Education, Ithaca, NY (United States)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Cornell Lab. for Accelerator-Based Sciences and Education, Ithaca, NY (United States); Cornell Univ., Ithaca, NY (United States)
- Illinois Inst. of Technology, Chicago, IL (United States)
Here, we present an analysis of Nb3Sn surface layers grown on a bulk Nb coupon prepared at the same time and by the same vapor diffusion process used to make Nb3Sn coatings on 1.3 GHz Nb cavities. Tunneling spectroscopy reveal a well developed, homogeneous superconducting density of states at the surface with a gap value distribution centered around 2.7 ± 0.4 meV and superconducting critical temperature's (Tc) up to 16.3K. Transmission electron microscopy (TEM) performed on cross sections of the sample's surface shows a ~ 2 microns thick Nb3Sn surface layer. The elemental composition map exhibits a Nb:Sn ratio of 3:1 with buried substoichiometric regions with a ratio of 5:1. Synchrotron diffraction experiments indicate a polycrystalline Nb3Sn film and confirm the presence of Nb rich regions that occupies about a third of the coating volume. These low Tc regions could play an important role in the dissipation mechanisms occurring during RF tests of Nb3Sn -coated Nb cavities and open the way for further improving a very promising alternative to pure Nb cavities for particle accelerators.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Materials Sciences and Engineering Division
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1354828
- Journal Information:
- Applied Physics Letters, Vol. 106, Issue 8; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Theory of RF superconductivity for resonant cavities
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journal | January 2017 |
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