Author: Berrutti, P.
Paper Title Page
MOPVA113 RF Quality Control of SRF Cavities for LCLS-II Cryo-Modules 1108
 
  • M.H. Awida, P. Berrutti, T.N. Khabiboulline, A. Lunin, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Funding: *Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
LCLS-II project is gearing up to build 36 cryo-modules of the 1.3 GHz TESLA style cavities. Half of those cryomodules are being built at Fermilab, while JLAB is carrying the production of the other half. In this paper, we present the process of quality controlling the RF performance of cavities until they are qualified for the final string assembly at Fermilab. The RF quality control process includes monitoring the frequency spectrum of each cavity and tuning/adjusting of the notch frequencies before testing at the Vertical Test Stand (VTS). Measured data during income QC is presented and in addition we show the notch frequencies before and after testing at the VTS. Moreover, we report some of the RF measurements taken while the cavity is cooled down to 2K temperature.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA113  
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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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