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Title: Pressurized rf cavities in ionizing beams

A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf) test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. In conclusion, energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF$$_6$$ and O$$_2$$ were measured.
 [1] ;  [2] ;  [2] ;  [3] ;  [1] ;  [4] ;  [4] ;  [1] ;  [5] ;  [6] ;  [2] ;  [2] ;  [7]
  1. Illinois Institute of Technology, Chicago, IL (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  3. Uslan National Institute of Science and Technology, Uslan (Korea)
  4. Muons, Inc., Batavia, IL (United States)
  5. Univ. of California, Santa Barbara, CA (United States)
  6. Institute for Plasma Research, Gandhinagar (India)
  7. Univ. of Michigan, Ann Arbor, MI (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2469-9888; 1472777
Grant/Contract Number:
Published Article
Journal Name:
Physical Review Accelerators and Beams (Online)
Additional Journal Information:
Journal Name: Physical Review Accelerators and Beams (Online); Journal Volume: 19; Journal Issue: 6; Journal ID: ISSN 2469-9888
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
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1287385