| Paper |
Title |
Page |
| MOPLS084 |
Experimental Comparison at KEK of High Gradient Performance of Different Single Cell Superconducting Cavity Designs
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750 |
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- F. Furuta, Y. Higashi, T. Higo, I.H. Inoue, S. Kazakov, Y. Kobayashi, H. Matsumoto, Y. Morozumi, R.S. Orr, T. Saeki, K. Saito, K. Ueno, H. Yamaoka
KEK, Ibaraki
- J.S. Sekutowicz
DESY, Hamburg
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We have performed a series of vertical tests of three different designs of single cell Niobium superconducting cavities at 2 degrees Kelvin. These tests aimed at establishing that an accelerating gradient of 45 MV/m could be reached in any of the designs, while using the standard KEK surface preparation. The designs tested were the Cornell re-entrant shape (RE), the DESY/KEK low loss shape (LL), and the KEK ICHIRO series. The cavities underwent surface preparation consisting of centrifugal barrel polishing, light chemical polishing, electropolishing, and finally a high pressure water rinse. All three kinds of cavities were used in a series of vertical tests to investigate details of the surface treatment. When using ultra-pure water for the high pressure rinse, the LL cavity reproducibly exceeded a gradient of 45 MV/m, the RE design reproducibly reached a gradient of between 50 MV/m and 52 MV/m, and three of the six ICHIRO cavities reached a gradient of between 45 MV/m and 49 MV/m.
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| THPCH176 |
Deposition of Lead Thin Films Used as Photo-cathodes by Means of Cathodic Arc under UHV Conditions
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3209 |
| |
- P. Strzyzewski, J. Langner, M. S. Sadowski, J. Witkowski
The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
- T. Rao, J. Smedley
BNL, Upton, Long Island, New York
- R. Russo, S. Tazzari
Università di Roma II Tor Vergata, Roma
- J.S. Sekutowicz
DESY, Hamburg
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The cathodic arc technology has been used for various technical purposes for many years. Recently, it has been demonstrated that the cathodic arc can be operated under ultra-high vacuum (UHV) conditions and it might solve the problem of the oxygen contamination coming from water remnants. It opens a new road to many applications where very pure metallic and/or superconducting films are needed. The paper reports on recent experimental studies aimed on the deposition of superconducting films of pure lead (Pb) by means of the UHV cathodic arc. Such layers can be used as photo-cathodes needed for modern accelerator injectors. The system configuration, used for thin film deposition inside the RF Gun designed at DESY, is also described and the main results and characteristics of thin superconducting Pb-films are presented.
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| THPLS092 |
Nb-Pb Superconducting RF-Gun
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3493 |
| |
- J.S. Sekutowicz, J.I. Iversen, D. Klinke, D. Kostin, W.-D. Möller
DESY, Hamburg
- I. Ben-Zvi, A. Burrill, T. Rao, J. Smedley
BNL, Upton, Long Island, New York
- M. Ferrario
INFN/LNF, Frascati (Roma)
- P. Kneisel
Jefferson Lab, Newport News, Virginia
- K. Ko, L. Xiao
SLAC, Menlo Park, California
- J. Langner, P. Strzyzewski
The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
- R.S. Lefferts, A.R. Lipski
SBUNSL, Stony Brook, New York
- J.B. Rosenzweig
UCLA, Los Angeles, California
- K. Szalowski
University of Lodz, Lodz
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We report on the status of an electron RF-gun made of two superconductors: niobium and lead. The presented design combines the advantages of the RF performance of bulk niobium superconducting cavities and the reasonably high quantum efficiency of lead, as compared to other superconducting metals. The concept, mentioned in a previous paper, follows the attractive approach of all niobium superconducting RF-gun as it has been proposed by the BNL group. Measured values of quantum efficiency for lead at various photon energies, analysis of recombination time of photon-broken Cooper pairs for lead and niobium, and preliminary cold test results are discussed in this paper.
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