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Q-factor optimization for high-beta 650 MHz cavities for PIP-II

Journal Article · · Journal of Applied Physics
DOI:https://doi.org/10.1063/5.0068531· OSTI ID:1832813
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  1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
+ Show Author Affiliations
High Q-factors are of utmost importance to minimize losses of superconducting radio-frequency cavities deployed in continuous wave particle accelerators. This study elucidates the surface treatment that can maximize the Q-factors in high-beta 650 MHz elliptical niobium cavities. State-of-the-art surface treatments are applied in many single-cell cavities, and surface resistance studies are performed to understand the microwave dissipation at this unexplored frequency. The nitrogen doping treatment is confirmed to be necessary to maximize the Q-factors at medium RF fields. We applied this treatment in five-cell high-beta 650 MHz cavities and demonstrated that extremely high Q-factors were obtained at medium RF fields with this treatment. We also demonstrated that adding a cold electropolishing step after N-doping is crucial to push the quench field of multicell cavities to higher gradients.
Research Organization:
Argonne National Laboratory (ANL), Argonne, IL (United States); Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)
Sponsoring Organization:
USDOE; USDOE Office of Science (SC), High Energy Physics (HEP)
Grant/Contract Number:
AC02-06CH11357; AC02-07CH11359
OSTI ID:
1832813
Alternate ID(s):
OSTI ID: 1828451
OSTI ID: 1869168
Report Number(s):
FERMILAB-PUB--21-651-SQMS-TD; arXiv:2111.01894; oai:inspirehep.net:1959783
Journal Information:
Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 130; ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English

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Related Subjects

43 PARTICLE ACCELERATORS
niobium
particle accelerators
radiofrequency cavities
superconducting devices
superconductivity