Author: Ohnishi, Y.
Paper Title Page
MOXAT0103 SuperKEKB Luminosity Quest 1
 
  • Y. Ohnishi
    KEK, Ibaraki, Japan
 
  The SuperKEKB accelerator is a positron-electron collider with a nano-beam scheme and continues to achieve the world’s highest luminosity for the production of B meson pairs. The luminosity performance has been improved by the full-scale adoption of the crab-waist scheme. The nano-beam scheme allows the vertical beta function at the interaction point to be much smaller than the bunch length. The vertical beta function and the beam size at the collision point are the smallest in the world among colliders. As the result, the peak luminosity of 4.65 x 1034 cm-2 s-1 has been achieved with the Belle II detector in 2022. Recent progress will be presented, and then the problems and issues to be overcome from the beam physics point of view will be discussed for further improvement of luminosity performance in the future.  
slides icon Slides MOXAT0103 [27.057 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-eeFACT2022-MOXAT0103  
About • Received ※ 25 October 2022 — Revised ※ 02 February 2023 — Accepted ※ 07 February 2023 — Issue date ※ 10 February 2023
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TUXAT0103 SuperKEKB Optics Tuning and Issues 35
 
  • H. Sugimoto, H. Koiso, A. Morita, Y. Ohnishi
    KEK, Ibaraki, Japan
 
  SuperKEKB is an electron-positron double-ring asymmetric-energy collider at the High Energy Accelerator Research Organization (KEK) in Japan. It adopts a novel collision method named nano-beam scheme to avoid the so-called hourglass effect. In the nano-beam scheme, two beams are squeezed to extremely small sizes at the interaction point and are collided with a large crossing angle between them. Since staring the collision operation in April 2018, numerous machine tunings and beam studies have been performed to improve the machine performance. The highest peak luminosity so far is 4.65 x 1034 cm-2 s-1 reached in June 8th, 2022. This record is the world’s highest instantaneous luminosity and is more than 2 times higher than that of the previous KEKB collider. This talk starts with a brief introduction to SuperKEKB ring lattice design. The talk then presents some important topics related to beam optics tuning in the actual machine operation. Major issues to be resolved to boost the machine performance further are also addressed.  
slides icon Slides TUXAT0103 [23.011 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-eeFACT2022-TUXAT0103  
About • Received ※ 02 November 2022 — Revised ※ 07 February 2023 — Accepted ※ 08 February 2023 — Issue date ※ 09 February 2023
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WEXAT0101 Beam-beam Interaction in SuperKEKB: Simulations and Experimental Results 114
 
  • D. Zhou, Y. Funakoshi, K. Ohmi, Y. Ohnishi
    KEK, Ibaraki, Japan
  • Y. Zhang
    IHEP, Beijing, People’s Republic of China
 
  The beam-beam interaction is one of the most critical factors determining the luminosity performance of SuperKEKB. Simulations and experimental results from SuperKEKB have shown that a complete understanding of the beam-beam effects demands reliable models of 1) the nonlinear beam-beam interaction at the interaction point, 2) the one-turn lattice transfer map with machine imperfections, and 3) other intensity-dependent collective effects. The interplay of these factors makes it difficult to predict the luminosity performance of SuperKEKB via simulations. This paper continues the authors’ previous work* to discuss the beam-beam effects on luminosity in SuperKEKB.
* D. Zhou, Y. Funakoshi, K. Ohmi, Y. Ohnishi, and Y. Zhang, Simulations and Measurements of Luminosity at SuperKEKB, in Proc. IPAC’22, Bangkok, Thailand, Jun. 2022, pp. 2011-2014.
 
slides icon Slides WEXAT0101 [8.284 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-eeFACT2022-WEXAT0101  
About • Received ※ 26 November 2022 — Revised ※ 06 February 2023 — Accepted ※ 08 February 2023 — Issue date ※ 11 February 2023
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