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This content will become publicly available on November 22, 2018

Title: Effect of cooldown and residual magnetic field on the performance of niobium–copper clad superconducting radio-frequency cavity

Here, we present the results of rf measurements on a niobium–copper clad superconducting radio-frequency cavity with different cooldown conditions and residual magnetic field in a vertical test Dewar in order to explore the effect of thermal current induced magnetic field and its trapping on the performance of the cavity. The residual resistance, extracted from the Q 0( T) curves in the temperature range 4.3–1.5 K, showed no dependence on a temperature gradient along the cavity during the cooldown across the critical temperature up to ~50 K m –1. The rf losses due to the trapping of residual magnetic field during the cavity cooldown were found to be ~4.3 nΩ μT –1, comparable to the values measured in bulk niobium cavities. An increase of residual resistance following multiple cavity quenches was observed along with evidence of trapping of magnetic flux generated by thermoelectric currents.
ORCiD logo [1] ;  [1]
  1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Publication Date:
Report Number(s):
JLAB-ACC-17-2474; DOE/OR/23177-4144
Journal ID: ISSN 0953-2048; TRN: US1800194
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Superconductor Science and Technology
Additional Journal Information:
Journal Volume: 31; Journal Issue: 1; Journal ID: ISSN 0953-2048
IOP Publishing
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; niobium; superconducting cavities; flux expulsion; NbCu
OSTI Identifier: