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| THOAKI01 |
Advances in Large Grain/Single Crystal SC Resonators at DESY
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2569 |
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- W. Singer
- A. Brinkmann, A. Ermakov, J. Iversen, G. Kreps, A. Matheisen, D. Proch, D. Reschke, X. Singer, M. Spiwek, H. Wen
DESY, Hamburg
- P. Kneisel
Jefferson Lab, Newport News, Virginia
- M. Pekeler
ACCEL, Bergisch Gladbach
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The main aim of the DESY large grain R&D program is to check whether this option is reasonable to apply for fabrication of ca. 1'000 XFEL cavities. Two aspects are being pursued. On one hand the basic material investigation, on the other hand the material availability, fabrication and preparation procedure. Several single cell large grain cavities of TESLA shape have been fabricated and tested. The best accelerating gradients of 41 MV/m was measured on electropolished cavity. First large grain nine-cell cavities worldwide have been produced under contract of DESY with ACCEL Instruments Co. All three cavities fulfil the XFEL specification already in first RF test after only BCP (Buffered Chemical Polishing) treatment and 800 degrees C annealing. Accelerating gradient of 27 - 29 MV/m was reached. A fabrication method of single crystal cavity of ILC like shape was proposed. A single cell single crystal cavity was build at the company ACCEL. Accelerating gradient of 37.5 MV/m reached after only 112 microns BCP and in situ baking 120 degrees C for 6 hrs with the quality factor higher as 2x1010. The developed method can be extended on fabrication of multi cell single crystal cavities.
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Slides
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| THOAKI02 |
The Cornell ERL Superconducting 2-Cell Injector Cavity String and Test Cryomodule
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2572 |
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- M. Liepe
- S. A. Belomestnykh, E. P. Chojnacki, V. Medjidzade, H. Padamsee, P. Quigley, J. Sears, V. D. Shemelin, V. Veshcherevich
CLASSE, Ithaca
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Funding: Work supported by NSF.
Cornell University is developing and fabricating a SRF injector cryomodule for the acceleration of the high current (100 mA) beam in the Cornell ERL prototype and ERL light source. Major challenges include emittance preservation of the low energy, ultra low emittance beam, cw cavity operation, and strong HOM damping with efficient HOM power extraction. Prototypes have been completed for the 2-cell niobium cavity with helium vessel, coaxial blade tuner with piezo fine tuners, twin high power input couplers, and beam line HOM absorbers loaded with ferrites and ceramics. Axial symmetry of HOM absorbers, together with two symmetrically placed input couplers per cavity, avoids transverse on-axis fields, which would cause emittance growth. A one-cavity cryostat has been designed following concepts of the TTF cryostat, and is presently under fabrication and assembly. The cryostat design has been optimized for precise cavity alignment, good magnetic shielding, and high dynamic cryogenic loads from the RF cavities, input couplers, and HOM loads. In this paper we report on the status of the assembly and first test of the one-cavity test cryostat.
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Slides
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| THOAKI03 |
Revision of Accelerating and Damping Structures for KEK STF 45 MV/m Accelerator Modules
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2575 |
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- Y. Morozumi
- F. Furuta, T. Higo, T. Saeki, K. Saito
KEK, Ibaraki
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KEK is constructing its superconducting RF test facility and installing 1.3 GHz superconducting accelerator structures. Learning from experience with our first 45MV/m 9-cell structures, we have revised accelerating structures as well as higher order mode dampers for improved performance. Problems found in the earlier structures are discussed and solutions are presented. New experimental results will be also reported.
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Slides
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| THOAKI04 |
Status of the Cryomodules for the SPIRAL 2 Superconducting LINAC
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2578 |
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- P. Bosland
- P.-E. Bernaudin, G. Devanz, A. Perolat, C. G. Thomas-Madec
CEA, Gif-sur-Yvette
- S. Blivet, T. Junquera, D. Longuevergne, F. Lutton, G. Martinet, G. Olry, H. Saugnac
IPN, Orsay
- R. Ferdinand
GANIL, Caen
- M. Fruneau, Y. Gomez-Martinez, F. Vezzu
LPSC, Grenoble
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The SPIRAL 2 superconducting linac is composed of 2 cryomodule families. The first family in the low energy section, called cryomodules A, is composed of 12 cryomodules housing a single cavity at β=0.07. The second family in the high energy section, called cryomodules B, is composed of 7 cryomodules housing 2 cavities at β=0.12. The frequency of these QWR resonators is 88.050 MHz, and the design goal for the accelerating field Eacc is 6.5 MV/m. This paper describes the present status of the cryomodules development.
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