Paper |
Title |
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WEPRI053 |
Phase Method of Measuring Cavity Quality Factor |
2604 |
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- O.S. Melnychuk, R.V. Pilipenko, Y.M. Pischalnikov, W. Schappert, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
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Novel method for measuring intrinsic quality factor of superconducting RF (SRF) cavities using both amplitude and phase information of forward, reflected, and transmitted cavity signal is discussed. Advantages of the method in comparison with traditional types of cavity quality factor measurements are highlighted. Computer simulations and evaluation of uncertainties for the measurements are described. Analysis of data collected at vertical test facility for SRF cavities at Fermilab is presented.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI053
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WEPRI062 |
The Joint High Q0 R&D Program for LCLS-II |
2627 |
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- M. Liepe, R.G. Eichhorn, F. Furuta, G.M. Ge, D. Gonnella, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
- A.C. Crawford, A. Grassellino, A. Hocker, O.S. Melnychuk, A. Romanenko, A.M. Rowe, D.A. Sergatskov
Fermilab, Batavia, Illinois, USA
- R.L. Geng, A.D. Palczewski, C.E. Reece
JLab, Newport News, Virginia, USA
- M.C. Ross
SLAC, Menlo Park, California, USA
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The superconducting RF linac for LCLS-II calls for 1.3 GHz 9-cell cavities with an average intrinsic quality factor Q0 of 2.7·1010 at 2K and 16 MV/m accelerating gradient. A collaborative effort between Cornell University, FNAL, and JLab has been set up with the goal of developing and demonstrating a cavity treatment protocol for the LCLS-II cavities meeting these specifications. The high Q0 treatment protocol is based on nitrogen doping of the RF surface layer during a high temperature heat treatment. This novel SRF cavity preparation was recently developed at FNAL and shown to result in SRF cavities of very high Q0 at 2K with an increase in Q0 from low to medium fields. N-doped single cell cavities at Cornell, FNAL, and JLab routinely exceed LCLS-II specification. 9-cell N-doped cavities at FNAL achieve an average Q0(T=2K, 16 MV/m) of ≈ 3.4·1010 with an average quench field of ≈ 19 MV/m, meeting therefore overall with good margin the LCLS-II specification.
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DOI • |
reference for this paper
※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI062
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Export • |
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※ LaTeX,
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