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Title: Shielding superconductors with thin films as applied to rf cavities for particle accelerators

Determining the optimal arrangement of superconducting layers to withstand large-amplitude ac magnetic fields is important for certain applications such as superconducting radio-frequency cavities. In this paper, we evaluate the shielding potential of the superconducting-film–insulating-film–superconductor (SIS') structure, a configuration that could provide benefits in screening large ac magnetic fields. After establishing that, for high-frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters, we also solve numerically the Ginzburg-Landau equations. As a result, it is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [1]
  1. Cornell Univ., Ithaca, NY (United States)
  2. Brigham Young Univ., Provo, UT (United States)
  3. Peter Grunberg Institut, Julich (Germany)
Publication Date:
OSTI Identifier:
1224722
Report Number(s):
FERMILAB-PUB-15-547-TD
Journal ID: ISSN 2331-7019; PRAHB2; arXiv eprint number arXiv:1506.08428
Grant/Contract Number:
AC02-07CH11359; SC0002329; SC0008431
Type:
Published Article
Journal Name:
Physical Review Applied
Additional Journal Information:
Journal Volume: 4; Journal Issue: 4; Journal ID: ISSN 2331-7019
Publisher:
American Physical Society
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY