| 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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| MOPLS087 |
Series Test of High-gradient Single-cell Superconducting Cavity for the Establishment of KEK Recipe
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756 |
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- T. Saeki, F. Furuta, Y. Higashi, T. Higo, S. Kazakov, H. Matsumoto, Y. Morozumi, K. Saito, N. Toge, K. Ueno, H. Yamaoka
KEK, Ibaraki
- M.Q. Ge
IHEP Beijing, Beijing
- K. Kim
Kyungpook National University, Daegu
- R.S. Orr
University of Toronto, Toronto, Ontario
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We have performed a series of vertical tests of single cell Niobium superconducting cavities at 2 degrees Kelvin. These tests aimed at establishing the feasibility of reaching an accelerating gradient of 45 MV/m on a routine basis. The cavity profiles were all of the KEK low loss design and were fabricated from deep drawn Niobium half shells using electron beam welding. The cavity surface preparation followed an established KEK procedure of centrifugal barrel polishing, light chemical polishing, high temperature annealing, electropolishing, and finally a high pressure water rinse. Of the six cavities tested, three exceeded 45 MV/m on the first test. This clearly establishes the feasibility of this gradient. In this paper we describe these tests and our future program for optimising the surface preparation.
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| WEPCH166 |
Beam Test of Thermionic Cathode X-band RF-gun and Linac for Monochromatic Hard X-ray Source
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2319 |
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- K. Dobashi, A. Fukasawa, M. D. Meng, T. Natsui, F. Sakamoto, M. Uesaka, T. Yamamoto
UTNL, Ibaraki
- M. Akemoto, H. Hayano, T. Higo, J. Urakawa
KEK, Ibaraki
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A compact hard X-ray source based on laser-electron collision is proposed. The X-band linac is introduced to realize a very compact system. 2MeV electron beam with average current 2μampere at 10 pps, 200 ns of RF pulse is generated by a thermionic cathode X-band RF-gun. Beam acceleration and X-ray generation experiment by the X-band beam line are under way.
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| WEPCH182 |
Design of 9.4 GHz 950 keV X-band Linac for Nondestructive Testing
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2358 |
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- T. Yamamoto, T. Natsui, M. Uesaka
UTNL, Ibaraki
- M. Akemoto, S. Fukuda, T. Higo, M. Yoshida
KEK, Ibaraki
- K. Dobashi
The University of Tokyo, Nuclear Professional School, Ibaraki-ken
- E. Tanabe
AET Japan, Inc., Kawasaki-City
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Mobile "suit-case-sized" x-band (9.4GHz) 950 keV linac is designed for applications of nondestructive testing (NDT). Conventional device for the purpose is the S-band linac, but its drawback is a rather large device-size, large electron beam spot size of about 3 mm and lack of spatial resolution. We aim to realize the smaller spot size about 500 micro-m by a low emittance beam. The proposed system consists of the 9.4 GHz magnetron, modulator, thermionic RF electron gun and 9.4 GHz x-band linac and metal target for x-ray generation. The energy at the gun is 20 keV, and the final energy becomes 950 keV. Now, we are designing the linac structure of the pai/2 mode and analyzing the electromagnetic field (EMF) by SUPERFISH. At this time, we finish analyzing EMF of regular cavity cells and we are analyzing EMF of total accelerating tube. We have finished the detailed RF design. Further, we are also performing the design of the pai mode and going to discuss the advantages and drawbacks between them. Construction of the RF supplying system is underway. The detailed design parameters and updated status of the construction are presented at the spot.
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