Author: Michizono, S.
Paper Title Page
MOPCAV004 Mechanical Properties of Directly Sliced Medium Grain Niobium for 1.3 GHz SRF Cavity 259
 
  • A. Kumar, K. Abe, T. Dohmae, S. Michizono, T. Saeki, Y. Watanabe, A. Yamamoto, M. Yamanaka
    KEK, Ibaraki, Japan
  • A. Fajardo, N. Lannoy
    ATI, Albany, Oregon, USA
  • G.R. Myneni
    JLab, Newport News, Virginia, USA
  • G.R. Myneni
    BSCE, Yorktown, Virginia, USA
 
  At KEK, research is being conducted to manufacture cost-effective 1.3 GHz superconducting radio frequency cavities based on the fine grain (FG) and large grain (LG) Niobium (Nb) materials. Medium grain (MG) Nb has been proposed and developed as an alternative to the FG and LG Nb, being expected to have better mechanical stability with a cost-effective and clean manufacturing approach. MG Nb has an average grain size of 200 - 300 µm, which is approximately 100 times smaller than the LG Nb, however, there are occasional grains as large as 1-2 mm. As such, it is expected to have isotropic properties rather than the anisotropic properties of LG Nb. In this paper, we will outline the mechanical properties of the directly sliced high RRR MG Nb material (manufactured by ATI), and a comparative study will be presented with respect to FG and LG Nb. Moreover, the viability of MG Nb for the global high-pressure regulation for 1.3 GHz SRF cavity will be presented.  
poster icon Poster MOPCAV004 [1.791 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPCAV004  
About • Received ※ 21 June 2021 — Revised ※ 11 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 25 March 2022
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MOPCAV006 High-Q/High-G R&D at KEK Using 9-Cell TESLA-Shaped Niobium Cavities 268
 
  • R. Katayama, A. Araki, H. Ito, E. Kako, T. Konomi, S. Michizono, M. Omet, K. Umemori
    KEK, Ibaraki, Japan
 
  We will report on the current progress of High-Q/High-G R&D using three 1.3 GHz 9-cell TESLA shape niobium superconducting cavities at the High Energy Accelerator Research Organization (KEK). These cavities are made of bulk niobium of fine grain material with RRR >300 and have been annealed at 900 degrees for 3 hours. The cavity performances were evaluated at the Superconducting RF Test Facility at KEK (KEK-STF) after 2-step bake (70-75°C 4 h + 120°C 48 h), electropolishing at low temperature, and fast cooling procedure were applied to these cavities. In this study, obtained results will be compared with the baseline measurement for the standard recipe at KEK.  
poster icon Poster MOPCAV006 [1.876 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPCAV006  
About • Received ※ 22 June 2021 — Revised ※ 14 January 2022 — Accepted ※ 22 February 2022 — Issue date ※ 28 February 2022
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MOPCAV012 Fabrication of 1.3 GHz SRF Cavities Using Medium Grain Niobium Discs Directly Sliced from Forged Ingot 287
 
  • T. Dohmae, K. Abe, H. Inoue, A. Kumar, S. Michizono, T. Saeki, K. Umemori, Y. Watanabe, A. Yamamoto, M. Yamanaka, K. Yoshida
    KEK, Ibaraki, Japan
  • A. Fajardo, N. Lannoy
    ATI, Albany, Oregon, USA
  • G.R. Myneni
    JLab, Newport News, USA
 
  Medium grain (MG) niobium disc which is directly sliced from forged ingot is newly investigated for the cavity material. An effective cost reduction can be achieved using MG niobium since rolling process which is necessary for typical niobium sheet can be skipped during MG niobium production. Grain size of MD niobium is 200-300 um which is much smaller than large grain (LG) niobium directly sliced from melted niobium ingot. Hence, the formability of MG niobium is expected to be much better than LG niobium. KEK has started fabrication of cavity using MG niobium. In this talk, characteristic of MG niobium during fabrication will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPCAV012  
About • Received ※ 20 June 2021 — Revised ※ 12 July 2021 — Accepted ※ 21 August 2021 — Issue date ※ 17 September 2021
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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 [3.015 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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THOTEV02 Stable Beam Operation in cERL for Medical and Industrial Application at KEK 714
 
  • H. Sakai, M. Adachi, D.A. Arakawa, S. Eguchi, M.K. Fukuda, K. Haga, M. Hagiwara, K. Hara, K. Harada, N. Higashi, T. Honda, Y. Honda, T. Honma, M. Hosumi, E. Kako, Y. Kamiya, R. Kato, H. Kawata, Y. Kobayashi, Y. Kojima, T. Konomi, H. Matsumura, S. Michizono, C. Mitsuda, T. Miura, T. Miura, T. Miyajima, Y. Morikawa, S. Nagahashi, H. Nakai, N. Nakamura, K. Nakanishi, K.N. Nigorikawa, T. Nogami, T. Obina, F. Qiu, H. Sagehashi, M. Shimada, H. Shimizu, T. Shioya, M. Tadano, T. Takahashi, R. Takai, H. Takaki, O.A. Tanaka, Y. Tanimoto, A. Toyoda, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, M. Yamamoto
    KEK, Ibaraki, Japan
  • R. Hajima, K. Kawase
    QST, Tokai, Japan
  • N.P. Norvell
    SLAC, Menlo Park, California, USA
  • F. Sakamoto
    Akita National College of Technology, Akita, Japan
  • M. Shimada
    HSRC, Higashi-Hiroshima, Japan
 
  Funding: Supported by Accelerator Inc. and a New Energy and Industrial Technology Development Organization (NEDO) project and JSPS Grant-in-Aid for Scientific Research (KAKENHI) Grant Number JP18H03473.
A superconducting Compact Energy Recovery Linac (cERL) for electrons was constructed in 2013 at KEK to demonstrate energy recovery concept with low emittance, high-current CW beams of more than 10 mA for future multi-GeV ERL. Recently this cERL was operated not only to demonstrate energy recovery linac high current beam operation but also to promote and conduct a variety of industrial applications such as FEL, THz operation and Rare Isotope Production and irradiation for some materials. In this talk, I will present the status of the studies to realize the stable high-current low emittance CW beam and some applications with this beam.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THOTEV02  
About • Received ※ 19 June 2021 — Revised ※ 13 March 2022 — Accepted ※ 13 May 2022 — Issue date ※ 15 May 2022
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THPFDV008 Research on Ceramic for RF Window 771
 
  • Y. Yamamoto, K. Nakamura, H. Yoshizumi
    Kyocera Corporation, Corporate Fine Ceramics Group, Kyoto, Japan
  • S. Michizono, Y. Yamamoto
    KEK, Ibaraki, Japan
 
  Kyocera and KEK had started joint research on developing materials that satisfy the required characteristics as RF window materials. In previous studies, AO479B was developed, and it has been applied to some products. However, AO479B has size limitation in applying to products. Recently, large RF windows is demanded. Therefore, we have developed a new material AO479U which is designed to be applied to products regardless of the product size. In this report, the characteristics of AO479U was evaluated by comparing it with other materials, including the presence or absence of TiN coating. In order to clarify how the differences of materials or manufacturing processes contributes to heat generation and multipactor discharge occurring in RF windows, we measured important characteristics as RF window materials (relative permittivity, dielectric loss tangent, surface resistance, volume resistivity, secondary electron emission coefficient, and TiN thickness), and investigated the relationships of them and materials or manufacturing processes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-THPFDV008  
About • Received ※ 18 June 2021 — Revised ※ 06 December 2021 — Accepted ※ 28 February 2022 — Issue date ※ 01 May 2022
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