Author: Shimada, T.
Paper Title Page
TUPOTK052 Influence of a Positive Grid Biasing on RF System in J-PARC RCS 1336
 
  • M. Yamamoto, M. Nomura, H. Okita, T. Shimada, F. Tamura
    JAEA/J-PARC, Tokai-mura, Japan
  • K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
    KEK, Tokai, Ibaraki, Japan
 
  In order to accelerate a high intensity beam in the RCS, a large amplitude of the anode current is provided by a tube amplifier to compensate a heavy beam loading. Tetrode vacuum tubes are used in the RCS, and the control grid voltage enters into a positive region to feed such a large current. The positive grid biasing affects the waveform of the control grid voltage; it is deformed due to the induced control grid current under the condition of the multi-harmonic rf driving. Furthermore, the DC bias voltage drop on the control grid is observed because of the exceeding the ability for the control grid power supply. We describe the influence of the positive grid biasing in the RCS.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK052  
About • Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 24 June 2022
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WEPOTK004 Status and Upgrade Plan of the MR Ring RF Systems in J-PARC 2031
 
  • K. Hasegawa, K. Hara, C. Ohmori, Y. Sugiyama, M. Yoshii
    KEK, Tokai, Ibaraki, Japan
  • M. Nomura, H. Okita, T. Shimada, F. Tamura, M. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
 
  The J-PARC Main Ring (MR) is a high intensity proton accelerator and delivers 30 GeV proton beams for the long-base line neutrino experiment and the hadron experiments. At present, the beam intensity supplied to the neutrino experiment reached 520 kW with a cycle time of 2.48 s. Toward the design beam power of 750 kW and future goal of 1.3 MW, we chose shortening the MR operation cycle. Accelerating time is shortened in order to shorten the cycle, so a high accelerating voltage is required. Therefore, it is necessary to upgrade the RF systems. This RF upgrade expands the current nine RF systems to a total of thirteen. We are planning to fabricate four RF power sources and add four additional cavities that are recombined with existing cavities. The present status and upgrade plan of the MR RF systems are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK004  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 07 July 2022
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TUPOTK051 Design Studies on a High-Power Wide-Band RF Combiner for Consolidation of the Driver Amplifier of the J-PARC RCS 1333
 
  • H. Okita, K. Hara, K. Hasegawa, M. Nomura, T. Shimada, F. Tamura, M. Yamamoto
    KEK/JAEA, Ibaraki-Ken, Japan
  • C. Ohmori, Y. Sugiyama, M. Yoshii
    KEK, Ibaraki, Japan
  • M.M. Paoluzzi
    CERN, Meyrin, Switzerland
 
  A power upgrade of the existing 8 kW solid-state driver amplifier is required for the acceleration of high intensity proton beams in the J-PARC 3 GeV rapid cycling synchrotron (RCS). The development of a 25 kW amplifier with gallium nitride (GaN) HEMTs and based on 6.4 kW modules is ongoing. The combiner is a key component to achieve such a high output power over the wide bandwidth required for multi-harmonic rf operation. This paper presents a preliminary design of the combiner. The circuit simulation setup and results, including the realistic magnetic core characteristics and frequency response of the cables are reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK051  
About • Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022
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