Author: Hayano, H.
Paper Title Page
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 [3.015 MB]  
DOI • reference for this paper ※ https://doi.org/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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TUPFDV008 Instrumentation R&D for the Studies of SRF Thin-Film Structures at KEK and Kyoto University 421
 
  • Y. Fuwa
    JAEA/J-PARC, Tokai-mura, Japan
  • H. Hayano, H. Ito, R. Katayama, T. Kubo, T. Saeki
    KEK, Ibaraki, Japan
  • Y. Iwashita, Y. Kuriyama
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • H. Tongu
    Kyoto ICR, Uji, Kyoto, Japan
 
  We have been developing SRF instrumentations by which the effective lower critical magnetic field Hc1,eff of superconducting-material sample is evaluated through the method of the third-order harmonic voltage measurement mainly for the studies of new SRF thin-film structures. Recently, the quad coil system, which enables us to measure four samples simultaneously in a single batch of an experiment, has been developed. In order to study the creation of thin-film structures inside the SRF cavity, we developed 3-GHz-shaped coupon cavities and an XT-map system for the performance tests of 3 GHz cavities. This article reports the details of these works.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPFDV008  
About • Received ※ 01 July 2021 — Revised ※ 19 December 2021 — Accepted ※ 02 April 2022 — Issue date ※ 02 May 2022
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TUPCAV001 Vertical Electro-Polishing of 704 MHz Resonators Using Ninja Cathode: First Results 431
 
  • F. Éozénou, M. Baudrier, E. Cenni, E. Fayette, L. Maurice, C. Servouin
    CEA-DRF-IRFU, France
  • V. Chouhan, Y.I. Ida, K.N. Nii, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, H. Ito, S. Kato, T. Kubo, H. Monjushiro, T. Saeki
    KEK, Ibaraki, Japan
  • G. Jullien
    CEA-IRFU, Gif-sur-Yvette, France
 
  Vertical Electro-Polishing (VEP) of elliptical cavities using rotating Ninja cathodes (Marui Company patented technology) has continually been improved since 2012 and successfully applied for 1300MHz multicell ILC-type resonators. The goal of the presented study is to apply this technology to 704 MHz ESS-type resonators with both better Q0 and accelerating gradients in mind. We intend to demonstrate the superiority of VEP compared to standard Buffer Chemical Polishing (BCP), for possible applications such as MYRRHA accelerator. We describe here the promising results achieved on β=0.86 single-cell cavity after 200 µm uniform removal. The cavity quenched at 27 MV/m without any heat treatment. The surface resistance achieved was less than 5nΩ at 1.8K. Substantial performance improvement is expected after heat treatment of the cavity and additional 20 µm VEP sequence. A cathode for 5-Cell ESS cavity is concomitantly under design stage.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV001  
About • Received ※ 21 June 2021 — Revised ※ 16 August 2021 — Accepted ※ 23 August 2021 — Issue date ※ 17 March 2022
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THPCAV003 Impact of Vertical Electropolishing with Flipping System on Removal Uniformity and Surface State: Study with 9-Cell Niobium Coupon Cavity 783
 
  • K.N. Nii, V. Chouhan, Y.I. Ida, T.Y. Yamaguchi
    MGH, Hyogo-ken, Japan
  • H. Hayano, S. Kato, H. Monjushiro, T. Saeki
    KEK, Ibaraki, Japan
 
  We have been developing a vertical electropolishing (VEP) method for niobium superconducting RF cavities using a novel setup that allows periodic flipping of the cavity to put it upside down in the VEP process. The purpose of using the novel setup named as flipping system is to achieve uniform removal and smooth surface of the cavity. Previously, we have already introduced the VEP system and showed the preliminary results of VEP performed with the flipping system. In this article, we report VEP results obtained with a nine-cell coupon cavity. The results include detail on coupon currents with I-V curves for coupons, and impact of the cavity flipping on removal uniformity and surface morphology of the cavity.  
poster icon Poster THPCAV003 [1.261 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPCAV003  
About • Received ※ 19 June 2021 — Revised ※ 10 August 2021 — Accepted ※ 22 October 2021 — Issue date ※ 23 November 2021
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