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Title: High field Q slope and the effect of low-temperature baking at 3 GHz

Here, a strong degradation of the unloaded quality factor with field, called high field Q-slope, is commonly observed above B$$_{p}$$ $$\cong$$ 100 mT in elliptical superconducting niobium cavities at 1.3 GHz and 1.5 GHz. In the present experiments several 3 GHz niobium cavities were measured up to and above B$$_{p}$$ $$\cong$$100 mT. The measurements show that a high field Q-slope phenomenon limits the field reach at this frequency, that the high field Q-slope onset field depends weakly on the frequency, and that the high field Q-slope can be removed by the typical empirical solution of electropolishing followed by heating to 120 $$^{\circ}$$C for 48 hrs. In addition, one of the cavities reached a quench field of 174~mT and its field dependence of the quality factor was compared against global heating predicted by a thermal feedback model.
Authors:
 [1] ;  [2] ;  [2]
  1. Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Publication Date:
Report Number(s):
JLAB-ACC-17-2622; DOE/OR/23177-4310
Journal ID: ISSN 2469-9888; PRABCJ; TRN: US1801401
Grant/Contract Number:
AC05-06OR23177
Type:
Published Article
Journal Name:
Physical Review Accelerators and Beams
Additional Journal Information:
Journal Volume: 21; Journal Issue: 1; Journal ID: ISSN 2469-9888
Publisher:
American Physical Society (APS)
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
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
OSTI Identifier:
1418388
Alternate Identifier(s):
OSTI ID: 1419832