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Higashi, N.

Paper Title Page
MOPEB033 Operation of Superconducting Combined Function Magnet System for J-PARC Neutrino Beam Line 343
 
  • T. Ogitsu, Y. Ajima, O. Araoka, Y. Fujii, N. Hastings, N. Higashi, M. IIda, N. Kimura, T. Kobayashi, Y. Makida, T. Nakadaira, T. Nakamoto, H. Ohhata, T. Okamura, K. Sakashita, K. Sasaki, M. Shibata, S. Suzuki, K. Tanaka, A. Terashima, T. Tomaru, A. Yamamoto
    KEK, Ibaraki
  • A. Ichikawa
    Kyoto University, Kyoto
  • H. Kakuno
    University of Tokyo, Tokyo
 
 

A superconducting magnet system for the J-PARC neutrino beam line was completed at the end of 2008. The system consists of 14 doublet cryostats; each contains 2 combined function magnets (SCFM). The SCFM uses two single layer left/right asymmetric coils that produce a dipole field of 2.6 T and quadrupole of 19 T/m. By 2008, the world first SCFM had been developed and tested successfully at KEK. The mass-production was started in 2005, and completed by summer 2008. The system installation and commissioning took place from Feb. 2008 to Mar. 2009. The beam operation was started in April 2009 and the first neutrino beam was generated on April 23rd. Since then beam operation and commissioning to increase beam intensity has been performed to achieve the near term milestone of 100 kW beam operation. The paper briefly summarizes the history of SCFM development and the system construction as an introduction to a discussion on beam operation experience of the SCFM system.

 
MOPEB037 Development of Current Leads for the Superconducting Correctors in the SuperKEKB-IR 355
 
  • Z.G. Zong, N. Higashi, N. Ohuchi, M. Tawada, K. Tsuchiya
    KEK, Ibaraki
 
 

To supply the electrical power for the superconducting correctors in the interaction region of the proposed SuperKEKB, a kind of vapor cooled current leads is designed, which consists of 8 brass leads and can transport currents to 4 correctors simultaneously. The design current of the leads is about 50 A. The thermal and electrical behaviors have studied by the finite elements method and the cryogenic experiment is also planed to validate the performance. In this paper the design will be presented and the finite element model will be compared with the experimental data.

 
WEPE008 Construction of the S1-Global Cryomodules for ILC 3356
 
  • N. Ohuchi, H. Hayano, N. Higashi, E. Kako, Y. Kondou, H. Nakai, S. Noguchi, T. Saeki, M. Satoh, M. Sawabe, T. Shidara, T. Shishido, A. Terashima, K. Tsuchiya, K. Watanabe, A. Yamamoto, Y. Yamamoto, K. Yokoya
    KEK, Ibaraki
  • T.T. Arkan, S. Barbanotti, H. Carter, M.S. Champion, R.D. Kephart, J.S. Kerby, D.V. Mitchell, Y. Orlov, T.J. Peterson, M.C. Ross
    Fermilab, Batavia
  • A. Bosotti, C. Pagani, R. Paparella, P. Pierini
    INFN/LASA, Segrate (MI)
  • D. Kostin, L. Lilje, A. Matheisen, W.-D. Möller, H. Weise
    DESY, Hamburg
 
 

In an attempt at demonstrating an average field gradient of 31.5 MV/m as per the design accelerating gradient for ILC, a program called S1-Global is in progress as an international research collaboration among KEK, INFN, FNAL, DESY and SLAC. The S1-Global cryomodule will contain eight superconducting cavities from FNAL, DESY and KEK. The cryomodule will be constructed by joining two half-size cryomodules, each 6 m in length. The module containing four cavities from FNAL and DESY has been constructed by INFN. The module for four KEK cavities is being modified at present. The assembly of the cryomodules is scheduled from January 2010, and the operation of the system is scheduled from June 2010 at the KEK-STF. In this paper, the construction of the S1-Global cryomodule will be presented.

 
THPEA012 Various Observables of TW Accelerator Structures Operating 100MV/m or Higher at X-band Facility, Nextef of KEK 3699
 
  • T. Higo, T. Abe, M. Akemoto, S. Fukuda, N. Higashi, Y. Higashi, N.K. Kudo, S. Matsumoto, T. Shidara, T. Takatomi, K. Ueno, Y. Watanabe, K. Yokoyama, M. Yoshida
    KEK, Ibaraki
 
 

Under the CERN-SLAC-KEK collaboration, we have been developing the high gradient TW accelerator structures. One of the main focuses is the feasibility study of CLIC accelerator structure at X-band. A high power facility, Nextef*, was established at KEK in 2007. A few structures have been tested, including an un-damped disk-loaded structure successfully tested beyond 100 MV/m, a heavily damped structure to be tested from late 2009 and a structure made in a quadrant configuration. These structures follow the same accelerating-mode RF parameter profile, called CLIC-C**, but show different features at high gradient operation. Various observables, such as dark current, vacuum activities, light emission, breakdown rate, and so on, are measured. We discuss the high gradient phenomena related to these observables and the possible improvement for stable operation at a higher gradient.


* T. Higo et al., THP038, LINAC06,2006.
**A. Grudiev, http://indico.cern.ch/conferenceDisplay.py?confId=30911