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Title: Cryogenic rf test of the first SRF cavity etched in an rf Ar/Cl 2 plasma

Authors:
 [1];  [2];  [1];  [2];  [1];  [2];  [1]
  1. Department of Physics and Center for Accelerator Science, Old Dominion University, Norfolk, VA 23529, USA
  2. Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1414016
Grant/Contract Number:
SC0014397
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
AIP Advances
Additional Journal Information:
Journal Volume: 7; Journal Issue: 12; Related Information: CHORUS Timestamp: 2017-12-19 08:24:08; Journal ID: ISSN 2158-3226
Publisher:
American Institute of Physics
Country of Publication:
United States
Language:
English

Citation Formats

Upadhyay, J., Palczewski, A., Popović, S., Valente-Feliciano, A. -M., Im, Do, Phillips, H. L., and Vušković, L. Cryogenic rf test of the first SRF cavity etched in an rf Ar/Cl 2 plasma. United States: N. p., 2017. Web. doi:10.1063/1.4991888.
Upadhyay, J., Palczewski, A., Popović, S., Valente-Feliciano, A. -M., Im, Do, Phillips, H. L., & Vušković, L. Cryogenic rf test of the first SRF cavity etched in an rf Ar/Cl 2 plasma. United States. doi:10.1063/1.4991888.
Upadhyay, J., Palczewski, A., Popović, S., Valente-Feliciano, A. -M., Im, Do, Phillips, H. L., and Vušković, L. 2017. "Cryogenic rf test of the first SRF cavity etched in an rf Ar/Cl 2 plasma". United States. doi:10.1063/1.4991888.
@article{osti_1414016,
title = {Cryogenic rf test of the first SRF cavity etched in an rf Ar/Cl 2 plasma},
author = {Upadhyay, J. and Palczewski, A. and Popović, S. and Valente-Feliciano, A. -M. and Im, Do and Phillips, H. L. and Vušković, L.},
abstractNote = {},
doi = {10.1063/1.4991888},
journal = {AIP Advances},
number = 12,
volume = 7,
place = {United States},
year = 2017,
month =
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1063/1.4991888

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  • Recent applications in need of compact low-frequency deflecting and crabbing cavities have initiated the design and development of new superconducting structures operating at high gradients with low losses. Previously, TM{sub 110}-type deflecting and crabbing cavities had been developed and have also been in operation successfully. However these geometries are not favorable designs for low operating frequencies. The superconducting rf-dipole cavity is the first compact deflecting and crabbing geometry that has demonstrated high gradients and high shunt impedance. Since the fundamental operating mode is the lowest mode and is widely separated from the nearest higher order mode, the rf-dipole design ismore » an attractive geometry for effective damping of the higher order modes in high current applications. A 400 MHz rf-dipole cavity has been designed, fabricated, and tested as a proof-of-principle cavity. The cavity achieved high operating gradients, and the multipacting levels were easily processed and did not reoccur.« less
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  • Cosmic rays, thermal gas and magnetic fields in FRII radio cavities are assumed to come entirely from winds flowing from just behind the jet shocks. Combining analytic and computational methods, it is shown that the computed radio-electron energy distribution and synchrotron emissivity spectra everywhere in the Cygnus A radio cavity agree with radio observations of the Cygnus A lobes. The magnetic field energy density is small everywhere and evolves passively in the post-shock wind. Most synchrotron emission arises in recent post-shock material as it flows back along the radio cavity wall. Because it experienced less adiabatic expansion, the magnetic fieldmore » in this young backflow is larger than elsewhere in the radio lobe, explaining the observed radio synchrotron limb-brightening. The boundary backflow decelerates due to small cavity pressure gradients, causing large-scale fields perpendicular to the backflow (and synchrotron emission) to grow exponentially unlike observations. However, if the field is random on subgrid (sub-kpc) scales, the computed field reproduces both the magnitude and slowly decreasing radio synchrotron emissivity observed along the backflow. The radio synchrotron spectrum and image computed with a small-scale random field agree with Very Large Array observations. The total relativistic energy density in the post-jet shock region required in computations to inflate the radio cavity matches the energy density of relativistic electrons observed in the post-shock region of Cygnus A. This indicates that the component in the jet and cavity that dominates the dynamical evolution is a relativistic pair plasma.« less
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