Author: Ueki, R.
Paper Title Page
TUOFDV02
 Observation of Precise Distribution of Trapped Magnetic Flux Due to Quench by M&T Mapping System  
 
  • T. Okada
    Sokendai, Ibaraki, Japan
  • E. Kako, M. Masuzawa, H. Sakai, R. Ueki, K. Umemori
    KEK, Ibaraki, Japan
  • P. Pizzol, A. Poudel, T. Tajima
    LANL, Los Alamos, New Mexico, USA
  
  This study focused on the flux trapping of the superconducting cavity by measuring changes in the spatial magnetic field distribution for the Nb single-cell cavity using the magnetic field and temperature mapping system. The different external magnetic fields were applied when the cavity was vertically tested. The differences of magnetic field distribution were compared before and after flux trapping caused by quenches. The magnetic field mapping measured the magnetic field, including 3 axial directions, outside the equator of the cavity. Moreover, the local heating generated by the magnetic flux trapping was observed locally using temperature mapping. The result shows that the changes in the magnetic field distribution have the magnetic field components towards the quench location. In this presentation, the detail of experiments and results of the change of the magnetic field distribution and the local heating will be presented.  
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TUPFAV003 Stable Beam Operation at 33 MV/m in STF-2 Cryomodules at KEK 382
 
  • Y. Yamamoto, M. Akemoto, D.A. Arakawa, A. Araki, S. Araki, A. Aryshev, T. Dohmae, M. Egi, M.K. Fukuda, K. Hara, H. Hayano, Y. Honda, T. Honma, H. Ito, E. Kako, H. Katagiri, R. Katayama, M. Kawamura, N. Kimura, Y. Kojima, Y. Kondou, T. Konomi, M. Masuzawa, T. Matsumoto, S. Michizono, Y. Morikawa, H. Nakai, H. Nakajima, K. Nakanishi, M. Omet, T. Oyama, T. Saeki, H. Sakai, H. Shimizu, S.I. Takahara, R. Ueki, K. Umemori, A. Yamamoto
    KEK, Ibaraki, Japan
  • S. Aramoto
    Hiroshima University, Higashi-Hiroshima, Japan
  • M. Kuriki
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
  • Z.J. Liptak
    HU/AdSM, Higashi-Hiroshima, Japan
  • K. Sakaue
    The University of Tokyo, The School of Engineering, Tokyo, Japan
  • A. Yamamoto
    CERN, Meyrin, Switzerland
  
  In STF at KEK, as the operational demonstration of the SRF accelerator for ILC, the STF-2 cryomodules (CM1+CM2a: one and half size CM with 12 cavities) have achieved 33 MV/m as average accelerating gradient with 7 cavities in Mar/2019. After that, one cavity with the lowest performance installed in CM2a was replaced with one N-infused cavity developed for High-Q/High-G R&D between Japan and US. From this April, the beam operation started again and those CMs achieved 33 MV/m as average accelerating gradient with 9 cavities including one N-infused cavity again. This is the very important milestone for ILC. In this report, the detailed results will be presented.  
poster icon Poster TUPFAV003 [3.020 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-SRF2021-TUPFAV003  
About • Received ※ 21 June 2021 — Revised ※ 11 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 01 November 2021
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