Author: Grassellino, A.
Paper Title Page
MOPVA127 Vertical Test Results for the LCLS-II 1.3 GHz First Article Cavities 1152
 
  • A. Burrill, D. Gonnella, M.C. Ross
    SLAC, Menlo Park, California, USA
  • G.K. Davis, A.D. Palczewski, L. Zhao
    JLab, Newport News, Virginia, USA
  • A. Grassellino, O.S. Melnychuk
    Fermilab, Batavia, Illinois, USA
 
  The LCLS-II project requires 35 1.3 GHz cryomodules to be installed in the accelerator in order to deliver a 4 GeV electron beam to the undulators hall. These 35 cryomodules will consist of 8 1.3 GHz TESLA style SRF cavities, a design most recently used for the XFEL project in Hamburg, Germany. The cavity design has remained largely unchanged, but the cavity treatment has been modified to utilize the nitrogen doping process to allow for Quality factors in excess of 3x1010 at 16 MV/m, the designed operating gradient of the cavities in the CM. Two industrialized vendors are producing most of the SRF cavities for these cryomodules; and the performance of the first article cavities, 16 from each vendor, will be reported on in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA127  
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MOPVA128 RF Performance of Nitrogen-Doped Production SRF Cavities for LCLS-II 1156
 
  • D. Gonnella, A. Burrill, M.C. Ross
    SLAC, Menlo Park, California, USA
  • S. Aderhold, A. Grassellino, C.J. Grimm, T.N. Khabiboulline, O.S. Melnychuk, S. Posen, D.A. Sergatskov
    Fermilab, Batavia, Illinois, USA
  • E. Daly, G.K. Davis, F. Marhauser, K.M. Wilson
    JLab, Newport News, Virginia, USA
 
  Funding: DOE and the LCLS-II Project
The Linac Coherent Light Source II (LCLS-II) requires 280 9-cell superconducting RF cavities for operation in continuous wave mode. Two vendors have previously been selected to produce the cavities, Research Instruments GmbH and Ettore Zanon S.p.a. Here we present results from manufacturing and cavity preparation for the cavities constructed at these two vendors for LCLS-II. We show how the cavity preparation method has been changed mid-production in order to improve flux expulsion in the cavities and maintain high performance in realistic magnetic field environments (~5 mG). Additionally, we show that the nitrogen-doping process has been carried out successfully and repeatedly on over 70 cavities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA128  
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THOBB2
Plasma Processing R&D for LCLS-II Cavities  
 
  • M. Martinello, S. Aderhold, P. Berrutti, A. Grassellino, T.N. Khabiboulline
    Fermilab, Batavia, Illinois, USA
  • A. Burrill, D. Gonnella, G. Lanza, C.-K. Ng, M.C. Ross, L. Xiao
    SLAC, Menlo Park, California, USA
  • M. Doleans
    ORNL, Oak Ridge, Tennessee, USA
 
  Field emission is one the major limitations to the maximum usable accelerating gradient of SRF cavities in cryomodules. Taking advantage of the plasma chemistry, field emitting particles may be preferentially attacked with the purpose of modifying the work function, smoothing the particle shape or even removing completely the field emitter. Relying on this idea, a collaboration between FNAL, SLAC and ORNL was established with the purpose of building a plasma processing system as a tool capable to minimize and overcome the problem of field emission in LCLS-II cryomodules. The plasma processing system is inspired to the one already built at the Spallation Neutron Source (SNS), that is capable to process in-situ cavities from hydrocarbon contaminants, by means of a neon-oxygen reactive plasma mixture. Here we show an innovative RF design that has been optimized in order to ignite the plasma using a mixture of fundamental pass-band and high order modes. In addition, the first results obtained on contaminated samples and single-cell cavities are shown together with the future plan of the project.  
slides icon Slides THOBB2 [9.433 MB]  
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THPPA2
IPAC'17 Frank Sacherer Prize Winner Presentation  
 
  • A. Grassellino
    Fermilab, Batavia, Illinois, USA
 
  to be updated  
slides icon Slides THPPA2 [28.584 MB]  
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