WE2A —  Technology   (28-Sep-16   11:00—12:30)
Chair: H. Weise, DESY, Hamburg, Germany
Paper Title Page
WE2A01
N-Doping: The New Breakthrough Technology for SRF Cavities  
 
  • M. Martinello
    Fermilab, Batavia, Illinois, USA
 
  Modern projects of accelerators for High Energy Physics and FEL accelerators (PIP II, LCLS II, etc.) demand operation of the SRF cavities in CW regime. In this situation, low cryogenic losses are essential. Decrease of the losses or, thus, increase of the cavity unloaded quality factor Q0 allows great savings in capital and operational cost. The new N-doping technique for the SRF cavity processing in order to achieve high Q0 is described, which is now a ready-to-use technology for SRF accelerators. The current implementation of this technique for the LCLS-II cavity production, allow us to present how ultra-high Q-factors can be maintained from the vertical to the horizontal test. In particular, efficient cooling and optimization of shielding design will be discussed to address potential Q degradation from the remnant magnetic fields in the cryomodule. The talk will go through the physics and fundamental studies that allowed us a) to define the best nitrogen doping treatment which minimizes the Q sensitivity to trapped magnetic field, b) to maximize magnetic flux expulsion based on cavity treatment.  
slides icon Slides WE2A01 [3.101 MB]  
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WE2A02 FRIB Cryomodule Design and Production 673
 
  • T. Xu, H. Ao, B. Bird, N.K. Bultman, E.E. Burkhardt, F. Casagrande, C. Compton, J.L. Crisp, K.D. Davidson, K. Elliott, A. Facco, V. Ganni, A. Ganshyn, W. Hartung, M. Ikegami, P. Knudsen, S.M. Lidia, I.M. Malloch, S.J. Miller, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, L. Popielarski, M.A. Reaume, K. Saito, S. Shanab, G. Shen, M. Shuptar, S. Stark, J. Wei, J.D. Wenstrom, M. Xu, Y. Xu, Y. Yamazaki, Z. Zheng
    FRIB, East Lansing, Michigan, USA
  • A. Facco
    INFN/LNL, Legnaro (PD), Italy
  • K. Hosoyama
    KEK, Ibaraki, Japan
  • M.P. Kelly
    ANL, Argonne, Illinois, USA
  • R.E. Laxdal
    TRIUMF, Vancouver, Canada
  • M. Wiseman
    JLab, Newport News, Virginia, USA
 
  Funding: U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB), under con-struction at Michigan State University, will utilize a driver linac to accelerate stable ion beams from protons to ura-nium up to energies of >200 MeV per nucleon with a beam power of up to 400 kW. Superconducting technology is widely used in the FRIB project, including the ion sources, linac, and experiment facilities. The FRIB linac consists of 48 cryomodules containing a total of 332 superconducting radio-frequency (SRF) resonators and 69 superconducting solenoids. We report on the design and the construction of FRIB cryomodules.
 
slides icon Slides WE2A02 [3.823 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-WE2A02  
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WE2A03 Plasma Processing to Improve the Performance of the SNS Superconducting Linac 679
 
  • M. Doleans, R. Afanador, J.A. Ball, D.L. Barnhart, W. Blokland, M.T. Crofford, B. DeGraff, S.W. Gold, B.S. Hannah, M.P. Howell, S.-H. Kim, S.W. Lee, J.D. Mammosser, C.J. McMahan, T.S. Neustadt, J. Saunders, S.E. Stewart, W.H. Strong, P.V. Tyagi, D.J. Vandygriff, D.M. Vandygriff
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This work was supported by SNS through UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. DOE.
An in-situ plasma processing technique has been developed at the Spallation Neutron Source (SNS) to improve the performance of the superconducting radio-frequency (SRF) cavities in operation. The technique uses a low-density reactive neon-oxygen plasma at room-temperature to improve the surface work function, to help removing adsorbed gases on the RF surface and to reduce its secondary emission yield. Recently, the plasma processing technique has been applied to one offline cryomodule and to two cryomodules in the linac tunnel. Improvement of the accelerating gradient has been observed in all three cryomodules.
 
slides icon Slides WE2A03 [4.433 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-WE2A03  
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WE2A04
Integration of Superconducting Solenoids in Long Cryomodules  
 
  • S.H. Kim, Z.A. Conway, M. Kedzie, M.P. Kelly, P.N. Ostroumov, T. Reid
    ANL, Argonne, Illinois, USA
  • W. McGhee
    Cryomagnetics, Inc., Tennessee, USA
 
  Superconducting (SC) solenoids provide efficient focusing of ion beams in SC linacs. This talk will discuss design, installation and operational experience of long cryomodules containing multiple SC solenoids. The techniques for the alignment of cavity-solenoid string will be presented. The solenoid assemblies include X-, Y-steering coils and does not require any iron shielding. The studies of SRF cavity properties after the quenching next to the solenoid will be presented.  
slides icon Slides WE2A04 [2.191 MB]  
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