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This content will become publicly available on July 21, 2015

Title: Radio frequency magnetic field limits of Nb and Nb3Sn

Superconducting radio frequency (srf) cavities, essential components of many large particle accelerators, rely on the metastable flux-free state of superconducting materials. In this Letter, we present results of experiments measuring the magnetic field limits of two srf materials, Nb and Nb3Sn. Resonators made using these materials were probed using both high power rf pulses and dc magnetic fields. Nb, which is the current standard material for srf cavities in applications, was found to be limited by the superheating field Hsh when prepared using methods to avoid excessive rf dissipation at high fields. Nb3Sn, which is a promising alternative material that is still in the early stages of development for srf purposes, was found to be limited between the onset field of metastability Hc1 and Hsh. Furthermore, analysis of the results shows that the limitation is consistent with nucleation of flux penetration at defects in the rf layer.
Authors:
 [1] ;  [1] ;  [1]
  1. Cornell Lab. for Accelerated-Based Sciences and Education, Ithaca, NY (United States)
Publication Date:
OSTI Identifier:
1198713
Report Number(s):
FERMILAB-PUB-15-548-TD
Journal ID: ISSN 0031-9007; PRLTAO
Grant/Contract Number:
AC02-07CH11359; ER41628
Type:
Published Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 115; Journal Issue: 4; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
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:
43 PARTICLE ACCELERATORS; 36 MATERIALS SCIENCE