Author: Shobuda, Y.
Paper Title Page
TUA4I2 1-MW Beam Operation at J-PARC RCS with Minimum Beam Loss 147
 
  • P.K. Saha, H. Harada, H. Hotchi, K. Okabe, H. Okita, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yoshimoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
 
  The 3-GeV RCS of J-PARC now operates at high-intensity to nearly the designed 1 MW beam. The beam loss and the corresponding residual radiation is one of the key limitations against beam intensity ramp up. Recently, by a series of beam studies and feedback from numerical simulations, we have well mitigated the beam loss to a minimum level and also reduced the beam emittances for beam operation to the spallation neutron source as well as to the main ring. The residual beam loss at the designed 1 MW beam power occurs mostly due to the unavoidable foil scattering beam loss during multi-turn injection, while other beam loss sources have been well mitigated to realize a stable and higher availability beam operation at a nearly 1 MW beam power.  
slides icon Slides TUA4I2 [2.303 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4I2  
About • Received ※ 02 October 2023 — Revised ※ 07 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 21 October 2023
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TUC4I1 A Kicker Impedance Reduction Scheme with Diode Stack and Resistor at the RCS in J-PARC 162
 
  • Y. Shobuda, H. Harada, P.K. Saha, T. Takayanagi, F. Tamura, T. Togashi, Y. Watanabe, K. Yamamoto, M. Yamamoto
    JAEA/J-PARC, Tokai-mura, Japan
 
  At the 3-GeV Rapid Cycling Synchrotron (RCS) within the Japan Proton Accelerator Research Complex (J-PARC), kicker impedance causes beam instability. A 1-MW beam with a large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) by suppressing beam instabilities without the need for a transverse feedback system¿simply by turning off the sextuple magnets. However, we require other high-intensity and high-quality beams with smaller emittances for the Main Ring (MR). To address this, we proposed a scheme for suppressing the kicker impedance using a diode stack and resistors, which effectively reduces beam instability. Importantly, these devices have a negligible effect on the extracted beam from the RCS.  
slides icon Slides TUC4I1 [2.713 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-TUC4I1  
About • Received ※ 26 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 10 October 2023
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WEC3C1 Beyond 1-MW Scenario in J-Parc Rapid-Cycling Synchrotron 270
 
  • K. Yamamoto, T. Morishita, K. Moriya, H. Okita, P.K. Saha, Y. Shobuda, F. Tamura, I. Yamada, M. Yamamoto
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
 
  The 3-GeV rapid cycling synchrotron at the Ja-pan Pro-ton Accelerator Research Complex was designed to provid 1-MW proton beams to the Material and Life Sci-ence Experimental Facility and Main Ring. Thanks to the improvement works of the accelerator system, we success-fully accelerate 1-MW beam with quite small beam loss. Currently, the beam power of RCS is limited by the lack of anode current in the RF cavity system rather than the beam loss. Recently we developed a new acceleration cavity that can accelerate a beam with less anode current. This new cavity enables us not only to reduce require-ment of the anode power supply but also to accelerate more than 1-MW beam. We have started to consider the way to achieve beyond 1-MW beam acceleration. So far, it is expected that up to 1.5-MW beam can be accelerated after replacement of the RF cavity. We have also contin-ued study to achieve more than 2 MW beam in J-PARC RCS.  
slides icon Slides WEC3C1 [2.787 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-HB2023-WEC3C1  
About • Received ※ 25 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 26 October 2023
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