MOAD —  Contributed Orals (MC7)   (04-May-15   14:00—15:00)
Chair: M. Bai, FZJ, Jülich, Germany
Paper Title Page
MOAD1 Development of High Gradient RF System for J-PARC Upgrade 50
 
  • C. Ohmori, K. Hara, K. Hasegawa, M. Toda, M. Yoshii
    KEK, Ibaraki, Japan
  • M. Nomura, T. Shimada, F. Tamura, M. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
  • A. Schnase
    GSI, Darmstadt, Germany
 
  A new 5-cell cavity has been developed for the upgrade of the J-PARC Main Ring. In the cavity, high impedance magnetic alloy - Finemet FT3L, cores are loaded. The cavity was installed and has been used for the 250 kW beam operation. The cavity is operated with the RF voltage of 70 kV which is two times higher voltage than the present cavities. Eight more cavities will be assembled and installed in the next two years to increase the repetition rate of the Main Ring. This paper describes status of cavity operation under the beam loading and status of the mass productions of the cavities.  
slides icon Slides MOAD1 [2.551 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOAD1  
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MOAD2 RF Breakdown of 805 MHz Cavities in Strong Magnetic Fields 53
 
  • D.L. Bowring, A.V. Kochemirovskiy, M.A. Leonova, A. Moretti, M.A. Palmer, D.W. Peterson, K. Yonehara
    Fermilab, Batavia, Illinois, USA
  • B.T. Freemire
    IIT, Chicago, Illinois, USA
  • A.A. Haase
    SLAC, Menlo Park, California, USA
  • P.G. Lane, Y. Torun
    Illinois Institute of Technology, Chicago, Illinois, USA
  • D. Stratakis
    BNL, Upton, Long Island, New York, USA
 
  Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures in the presence of strong magnetic fields. We have measured the breakdown rate in several RF cavities operating at several frequencies. Cavities operating within solenoidal magnetic fields B > 0.25 T show an increased RF breakdown rate at lower gradients compared with similar operation when B = 0 T. Ultimately, this breakdown behavior limits the maximum safe operating gradient of the cavity. Beyond ionization cooling, this issue affects the design of photoinjectors and klystrons, among other applications. We have built an 805 MHz pillbox-type RF cavity to serve as an experimental testbed for this phenomenon. This cavity is designed to study the problem of RF breakdown in strong magnetic fields using various cavity materials and surface treatments, and with precise control over sources of systematic error. We present results from tests in which the cavity was run with all copper surfaces in a variety of magnetic fields.  
slides icon Slides MOAD2 [10.792 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOAD2  
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MOAD3 Relative Alignment Within the MAX IV 3 GeV Storage Ring Magnet Blocks 57
 
  • J.H. Björklund Svensson, M.A.G. Johansson
    MAX-lab, Lund, Sweden
 
  Unlike the discrete magnet scheme of previous 3rd generation light sources, the magnet elements of the MAX IV storage rings are integrated in precision-machined magnet blocks. By analyzing the rotating coil measurements made by the magnet suppliers, we determined the relative alignment between consecutive magnet elements, which was found to be <10 microns RMS for all magnet block types in both horizontal and vertical direction. This article presents our analysis and results for the full magnet production series.  
slides icon Slides MOAD3 [1.825 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOAD3  
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