Author: Nakamura, S.
Paper Title Page
MOPLXGD1 The SuperKEKB Has Broken the World Record of the Luminosity 1
 
  • Y. Funakoshi, T. Abe, K. Akai, Y. Arimoto, K. Egawa, S. Enomoto, H. Fukuma, K. Furukawa, N. Iida, H. Ikeda, T. Ishibashi, S.H. Iwabuchi, H. Kaji, T. Kamitani, T. Kawamoto, M. Kikuchi, T. Kobayashi, K. Kodama, H. Koiso, M. Masuzawa, K. Matsuoka, T. Mimashi, G. Mitsuka, F. Miyahara, T. Miyajima, T. Mori, A. Morita, S. Nakamura, T.T. Nakamura, K. Nakanishi, H.N. Nakayama, M. Nishiwaki, S. Ogasawara, K. Ohmi, Y. Ohnishi, N. Ohuchi, T. Okada, T. Oki, M.A. Rehman, Y. Seimiya, K. Shibata, Y. Suetsugu, H. Sugimoto, H. Sugimura, M. Tawada, S. Terui, M. Tobiyama, R. Ueki, X. Wang, K. Watanabe, S.I. Yoshimoto, T. Yoshimoto, D. Zhou, X. Zhou, Z.G. Zong
    KEK, Ibaraki, Japan
  • A. Natochii
    University of Hawaii, Honolulu,, USA
  • K. Oide
    CERN, Meyrin, Switzerland
  • R.J. Yang
    CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
  • K. Yoshihara
    Nagoya University, Nagoya, Aichi, Japan
 
  The SuperKEKB broke the world record of the luminosity in June 2020 in the Phase 3 operation. The luminosity has been increasing since then and the present highest luminosity is 4.65 x 1034 cm-2s-1 with βy* of 1 mm. The increase of the luminosity was brought with an application of crab waist, by increasing beam currents and by other improvements in the specific luminosity. In this paper, we describe what we have achieved and what we are struggling with. Finally, we mention a future plan briefly.  
slides icon Slides MOPLXGD1 [6.235 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPLXGD1  
About • Received ※ 10 June 2022 — Accepted ※ 08 July 2022 — Issue date ※ 10 July 2022  
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MOPOMS048 Fast Trigger System for Beam Abort System in SuperKEKB 754
 
  • H. Ikeda, T. Mimashi, S. Nakamura, T. Oki, S. Sasaki
    KEK, Ibaraki, Japan
 
  In order to protect the hardware components of the de-tector and accelerator from sudden beam loss of high beam currents, the fast beam abort system is developed in the SuperKEKB. The previous abort system was not fast enough for sudden beam loss that caused QCS quench, and it gave a damage to the collimator and the Belle-II detector. A fast abort system is required to pre-venting such damage. The abort system consists of sev-eral sensors that generate interlock signal (the loss moni-tor, dose in the Bell-II detector, and the magnet failure etc.), optical cable system to transfer the interlock signal to central control room (CCR), the abort trigger signal generation system and the abort kicker. To reduce total time, we reduce transmission time from local control room to CCR by changing signal cable route. Since the interlock signal produced by magnet power supply was slow, we modified the magnet power supply. For more quick generation of abort trigger signal, we increased number of the abort gap. By these improvements, an average abort time is reduced from 31µsec to 25µsec. This improvement looks small, but it brought preventing the serious radiation damage to many hardware compo-nents. Detail of the system and result is presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS048  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
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TUOZSP2
Chromatic X-Y Coupling Correction by Tilting Sextupole Magnets in the SuperKEKB Positron Ring  
 
  • M. Masuzawa, K. Egawa, Y. Funakoshi, T. Kawamoto, H. Koiso, A. Morita, S. Nakamura, K. Ohmi, Y. Ohnishi, R. Sugahara, H. Sugimoto, R. Ueki, D. Zhou
    KEK, Ibaraki, Japan
  • K. Oide
    CERN, Meyrin, Switzerland
 
  Chromatic x-y coupling correction at the interaction point was carried out using skew sextupole field created by tilting the sextupole magnets in the SuperKEKB positron ring. Twenty four sextupole magnets are mounted on a tilting table and their tilt angles can be varied form - 30 degree to + 30 degree remotely to control the ratio of the skew to normal sextupole magnetic field components. In the 2021c run, one of the chromatic coupling parameters was varied using different setups of the tilting angles of the 24 sextupole magnets for the first time in a collider. It was found that the emittance growth at the primary (nux-nuy-nus=n) and secondary (nux-nuy-2nus=n) synchro-beta resonance lines can be controlled by tilting the sextupole magnets. Luminosity increase followed after optimizing the chromatic coupling parameters and finding a better tune working point. The study results are summarized in the paper.  
slides icon Slides TUOZSP2 [19.499 MB]  
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