| Project/Area Number |
06044219
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | KEK,National Laboratory for High Energy Physics |
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Principal Investigator |
NOGUCHI Shuichi KEK,National Laboratory for High Energy Physics Associate Professor, 加速器研究部, 助教授 (80156182)
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| Co-Investigator(Kenkyū-buntansha) |
MATHEISEN Axel DESY, 加速器研究部, 研究員
SEKUTOWICZ Jacek DESY, 加速器研究部, 研究員
GAMP Alexander DESY, 加速器研究部, 主任研究員
PROCH Dieter DESY,Deutsches Elektronen-Synchrotron, 加速器研究部, 主任研究員
TAJIMA Tsuyoshi KEK, 加速器研究部, 助手 (50179694)
KAKO Eiji KEK, 加速器研究部, 助手 (60204351)
SAITO Kenji KEK, 加速器研究部, 助手 (10178478)
FURUYA Takaaki KEK, 加速器研究部, 助教授 (70156975)
ONO Masaaki KEK, 加速器研究部, 助教授 (50160916)
ISAGAWA Shigeru KEK, 加速器研究部, 教授 (20100810)
KUROKAWA Shin-ichi KEK, 加速器研究部, 教授 (90044776)
SEKUTOWICZ J ドイツシンクロトロン研究所, 加速器, 研究員
MATHEISEH Ax ドイツシンクロトロン研究所, 加速器, 研究員
PROCH Dieter ドイツシンクロトロン研究所, 加速器, 主研究員
GUMP Alexade ドイツシンクロトロン研究所, 加速器, 主研究員
肥後 壽泰 高エネルギー物理学研究所, 加速器, 助手 (10156581)
松本 浩 高エネルギー物理学研究所, 加速器, 助手 (90132688)
吉岡 正和 高エネルギー物理学研究所, 加速器, 助教授 (50107463)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥8,000,000 (Direct Cost: ¥8,000,000)
Fiscal Year 1995: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1994: ¥3,600,000 (Direct Cost: ¥3,600,000)
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| Keywords | Superconducting Cavity / High Accelerating Gradient / Quench / Field Emission |
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| Research Abstract |
An excellent performance of the superconducting cavity was demonstrated by the first large scale applcation to TRISTAN in KEK,and then confirmed by succeeding applications to big accelerators such as HERA,LEP and CEBAF.However, the operating gradient in these accelerators is still low, around 5MV/m.Even in laboratory tests, the maximum accelerating gradients of niobium cavities are below 30 MV/m, whereas the material parameter predicts 50 MV/m.The accelerating gradient is limited by either thermal quench or electron field emission, and these are believed to be caused by all kinds of imperfections such as dust contamination, scratch and chemical residue produced during manufacture and surface preparation.
The purposes of this research program are to clear the nature of imperfections which limit the accelerating gradient, to improve preparation processes which make such imperfections and to achieve higher accelerating gradients.
Until now, ten single-cell 1.3 GHz niobium cavities have been made from three different materials and tested repeatedly with different preparation conditions.The results can be summarized as follows.
1.The accelerating gadient of 30 MV/m becomes routinely achievable with 35 MV/m as the maximum gradient.
2.For the thermal conductivity of niobium, 50 W/mK is enough to achieve 30MV/m.The higher thermal conductivity is not helpful, but the maximum gradient is 20MV/m for the cavities made from 20 W/mK material.
3.High pressure (85kg/cm^2) water rinsing after chemical surface treatment can improve the accelerating gradient above 30MV/m, whereas it is below 25MV/m if not applied.
4.The effectiveness of high temperature (1300-1400ﾟC) heat treatment, which is confirmed at three laboratories, is not seen in our tests.This discrepancy is probably due to the effect of high pressure water rinsing which is applied only in KEK.
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