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https://doi.org/10.18429/JACoW-SRF2019-TUFUA1
Title The Field-Dependent Surface Resistance of Doped Niobium: New Experimental and Theoretical Results
Authors
  • J.T. Maniscalco, M. Ge, P.N. Koufalis, M. Liepe
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Arias, D. Liarte, J.P. Sethna, N. Sitaraman
    Cornell University, Ithaca, New York, USA
Abstract We present systematic work investigating how different doping and post-doping treatments affect the BCS surface resistance at 1.3~GHz and higher frequencies. We examine the field-dependent BCS resistance at many temperatures as well as the field-dependent residual resistance and use the results to reveal how impurity species and concentration levels affect the field-dependent RF properties. We further demonstrate the importance of thermal effects and their direct dependence on doping level. We use the tools of Density Functional Theory to work towards an {\em ab initio} model of electron overheating to theoretically confirm the impact of doping, create a full model that includes thermal effects to predict the field dependent resistance, and show that the predictions of the model agree with results from doped and non-doped cavities ({\em e.g.} the strength of the anti-Q-slope and the high-field Q slope). Finally, we use our experimental results to systematically assess and compare theories of the field-dependent BCS resistance, showing that the current theory on smearing of the density of states is incomplete.
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Conference SRF2019
Series International Conference on RF Superconductivity (19th)
Location Dresden, Germany
Date 30 June-05 July 2019
Publisher JACoW Publishing, Geneva, Switzerland
Editorial Board Peter Michel (HZDR, Dresden, Germany); André Arnold (HZDR, Dresden, Germany); Volker RW Schaa (GSI, Darmstadt, Germany)
Online ISBN 978-3-95450-211-0
Online ISSN ""
Received 01 July 2019
Accepted 02 July 2019
Issue Date 14 August 2019
DOI doi:10.18429/JACoW-SRF2019-TUFUA1
Pages 340-346
Copyright
Creative Commons CC logoPublished by JACoW Publishing under the terms of the Creative Commons Attribution 3.0 International license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI.