| Title |
A Three-Fluid Model of Dissipation at Surfaces in Superconducting Radiofrequency Cavities |
| Authors |
- M.M. Kelley, T. Arias, S. Deyo, D. Liarte, J.P. Sethna, N. Sitaraman
Cornell University, Ithaca, New York, USA
- M. Liepe, T.E. Oseroff
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
|
| Abstract |
Experiments on superconducting cavities have found that under large RF fields the quality factor can improve with increasing field amplitude, a so-called anti-Q slope. We numerically solve the Bogoliubov-de Gennes equations at a superconducting surface in a parallel magnetic field, finding at large fields there are surface quasiparticle states with energies below the bulk superconducting gap that emerge and disappear as the field cycles. Modifying the standard two-fluid model, we introduce a ‘‘three’’-fluid model where we partition the normal fluid to consider continuum and surface quasiparticle states separately. We compute dissipation in a semi-classical theory of conductivity, where we provide physical estimates of elastic scattering times of Bogoliubov quasiparticles with point-like impurities having potential strengths informed from complementary ab initio calculations of impurities in bulk niobium. We show, in this simple yet effective framework, how the relative scattering rates of surface and continuum quasiparticle states can play a role in producing an anti-Q slope while demonstrating how this model naturally includes a mechanism for turning the anti-Q slope on and off.
|
| Footnotes & References |
S. Deyo, M. Kelley et al. Phys. Rev. B 106, 104502 (2022) |
| Funding |
This work was supported by the U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams. |
| Paper |
download TUIBA01.PDF [0.366 MB / 8 pages] |
| Slides |
download TUIBA01_TALK.PDF [2.019 MB] |
| Cite |
download ※ BibTeX
※ LaTeX
※ Text/Word
※ RIS
※ EndNote |
| Conference |
SRF2023 |
| Series |
International Conference on RF Superconductivity (21st) |
| Location |
Grand Rapids, MI, USA |
| Date |
25-30 June 2023 |
| Publisher |
JACoW Publishing, Geneva, Switzerland |
| Editorial Board |
Kenji Saito (FRIB, MSU, East Lansing, MI, USA); Ting Xu (FRIB, MSU, East Lansing, MI, USA); Naruhiko Sakamoto (RIKEN, Wako, Japan); Volker R.W. Schaa (GSI, Darmstadt, Germany); Paul W. Thomas (FRIB, MSU, East Lansing, MI, USA) |
| Online ISBN |
978-3-95450-234-9 |
| Online ISSN |
2673-5504 |
| Received |
19 June 2023 |
| Revised |
23 June 2023 |
| Accepted |
28 June 2023 |
| Issue Date |
08 July 2023 |
| DOI |
doi:10.18429/JACoW-SRF2023-TUIBA01 |
| Pages |
361-368 |
| Copyright |
 Published by JACoW Publishing under the terms of the Creative Commons Attribution 4.0 International license. Any further distribution of this work must maintain attribution to the author(s), the published article's title, publisher, and DOI. |
|
