Author: Ego, H.
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MOPOST017 Design and Beam Dynamics Study of Disk-Loaded Structure for Muon Linac 94
 
  • K. Sumi, T. Iijima, K. Inami, Y. Sue, M. Yotsuzuka
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • H. Ego, T. Mibe, N. Saito, M. Yoshida
    KEK, Ibaraki, Japan
  • T. Iijima
    KMI, Nagoya, AIchi Prefecture, Japan
  • Y. Kondo, K. Moriya
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • Y. Nakazawa
    Ibaraki University, Hitachi, Ibaraki, Japan
  • M. Otani
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  • Y. Takeuchi
    Kyushu University, Fukuoka, Japan
  • H.Y. Yasuda
    University of Tokyo, Tokyo, Japan
 
  The disk-loaded structures (DLS) in the muon LINAC are under development for the J-PARC muon g-2/EDM experiment. Four DLSs with an accelerating gradient of 20 MV/m take charge of muon acceleration from 40 MeV to 212 MeV, which corresponds to 70% to 94% of the speed of light. The quasi-constant gradient type TM01-2pi/3 mode DLSs with gradually varying disk spacing was designed and confirmed that the cumulative phase slip due to the mismatch between muon and phase velocity can be suppressed to less than 2 degrees at the frequency of 2592 MHz. In addition, the optimum synchronous phase and the lattice were investigated to satisfy the requirements of the total emittance less than 1.5 pi mm mrad and the momentum spread less than 0.1% in RMS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST017  
About • Received ※ 19 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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TUPOMS046 Fabrication and Low-Power Test of Disk-and-Washer Cavity for Muon Acceleration 1534
 
  • Y. Takeuchi, J. Tojo
    Kyushu University, Fukuoka, Japan
  • E. Cicek, H. Ego, K. Futatsukawa, N. Kawamura, T. Mibe, M. Otani, N. Saito, T. Yamazaki, M. Yoshida
    KEK, Ibaraki, Japan
  • Y. Iwashita
    Kyoto University, Research Reactor Institute, Osaka, Japan
  • R. Kitamura, T. Morishita
    JAEA/J-PARC, Tokai-mura, Japan
  • Y. Kondo
    JAEA, Ibaraki-ken, Japan
  • Y. Nakazawa
    Ibaraki University, Hitachi, Ibaraki, Japan
  • Y. Sue, K. Sumi, M. Yotsuzuka
    Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
  • H.Y. Yasuda
    University of Tokyo, Tokyo, Japan
 
  The muon g-2/EDM experiment is under preparation at Japan Proton Accelerator Research Complex (J-PARC), and the muon linear accelerator for the experiment is being developed. A Disk-and-Washer (DAW) cavity will be used for the medium-velocity part of the accelerator, and muons will be accelerated from v/c=ß=0.3 to 0.7 with the operating frequency of 1.296 GHz. Machining, brazing, and low-power measurements of a prototype cell reflecting the design of the first tank of DAW were performed to identify fabrication problems. Several problems were identified, such as displacement of washers during brazing, and some measures will be taken in the actual tank fabrication. In this paper, the results of the prototype cell fabrication will be reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS046  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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THPOST011 SuperKEKB Electron Positron Injector Linac Upgrade for Higher Charge and Lower Emittance 2461
 
  • K. Furukawa, H. Ego, Y. Enomoto, N. Iida, T. Kamitani, M. Kawamura, S. Matsumoto, T. Matsumoto, T. Miura, M. Satoh, A. Shirakawa, T. Suwada, M. Yoshida
    KEK, Ibaraki, Japan
 
  KEK electron positron injector linac has established simultaneous top-up injections in 2019 for 5 rings of SuperKEKB DR, LER, HER, PF ring and PF-AR as a base of the both elementary particle physics and photon science experiments even under a quite short beam lifetime. It improved the injection stabilities while the SuperKEKB broke the world record of the collision luminosity of the previous project KEKB. As the collision performance improves, the beam-beam effect makes the dynamic aperture shrink, and the beam lifetime reduces further. Thus, it became inevitable for the injector to be upgraded in order to resolve the contradictory improvements of higher charge and lower emittance of injection beams regarding beam wakefield till 2025. The upgrade plan is described including pulsed magnets, an energy compression system, accelerating structures, girders, positron generator and so on.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST011  
About • Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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THPOST012 Achievement of 200, 000 Hours of Operation at KEK 7-GeV Electron 4-GeV Positron Injector Linac 2465
 
  • K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, H. Ego, Y. Enomoto, T. Higo, H. Honma, N. Iida, K. Kakihara, T. Kamitani, H. Katagiri, M. Kawamura, S. Matsumoto, T. Matsumoto, H. Matsushita, K. Mikawa, T. Miura, F. Miyahara, H. Nakajima, T. Natsui, Y. Ogawa, S. Ohsawa, Y. Okayasu, T. Oogoe, M.A. Rehman, I. Satake, M. Satoh, Y. Seimiya, T. Shidara, A. Shirakawa, H. Someya, T. Suwada, M. Tanaka, D. Wang, Y. Yano, K. Yokoyama, M. Yoshida, T. Yoshimoto, R. Zhang, X. Zhou
    KEK, Ibaraki, Japan
  • Y. Bando
    Sokendai, Ibaraki, Japan
 
  KEK electron positron injector linac initiated the injection operation into Photon Factory (PF) light source in 1982. Since then for 39 years, it has served for multiple projects, namely, TRISTAN, PF-AR, KEKB, and SuperKEKB. Its total operation time has accumulated 200 thousand hours on May 7, 2020. We are extremely proud of the achievement following continuous efforts by our seniors. The construction of the injector linac started in 1978, and it was commissioned for PF with 2.5 GeV electron in 1982. In parallel, the positron generator linac was constructed for the TRISTAN collider project. The slow positron facility was also commissioned in 1992. After the KEKB asymmetric-energy collider project was commissioned in 1998 with direct energy injections, the techniques such as two-bunch acceleration and simultaneous injection were developed. As the soft structure design of the linac was too weak against the great east Japan earthquake, it took three years to recover. Then the construction and commissioning for the SuperKEKB project went on, and the simultaneous top-up injection into four storage rings contributes to the both elementary particle physics and photon science.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST012  
About • Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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