Author: Funakoshi, Y.
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TUOBB01 Optics Aberration at IP and Beam-beam Effects 66
 
  • K. Ohmi, Y. Funakoshi, H. Koiso, A. Morita, Y. Ohnishi, D. Zhou
    KEK, Ibaraki, Japan
  • K. Hirosawa
    Sokendai, Ibaraki, Japan
  
  Collision in SuperKEKB phase II commissioning has started in April 2018. Luminosity was lower than the geomterical value even in very low bunch current. Linear x-y coupling at IP caused by skew of QCS was conjectured as error source. x-y coupling correction using skew corrector of QCS resulted in luminosity recover of 2 times. After the QCS skew correction, luminosity is still limited at relatively low bunch current. Nonlinear x-y coupling at IP is conjectured as a source of the luminosity limitation. We discuss effects of linear and nonlinear x-y coupling at IP on the beam-beam performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOBB01  
About • paper received ※ 25 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPAB07 Commissioning of Positron Damping Ring and the Beam Transport for SuperKEKB 152
 
  • N. Iida, Y. Funakoshi, H. Ikeda, T. Ishibashi, H. Kaji, T. Kamitani, M. Kikuchi, T. Kobayashi, H. Koiso, F. Miyahara, T. Mori, Y. Ohnishi, Y. Seimiya, H. Sugimoto, H. Sugimura, R. Ueki, Y. Yano, D. Zhou
    KEK, Ibaraki, Japan
  
  The Positron Damping Ring (DR) for SuperKEKB successfully started its operation in February 2018, and the commissioning was continued until the end of SuperKEKB Phase 2 in July without serious troubles. This paper describes achievements of the beam commissioning of injection and extraction lines (LTR and RTL) between the LINAC and DR. In the LTR commissioning, the positron beam with high emittance, wide energy spread, and high charge were transported and injected into the DR. In the RTL commissioning, special cares were necessary to preserve the low emittance. The observed emittance growth in the RTL was not a problem for Phase 2, but it should be resolved in the coming Phase 3. In this paper, brief results of the commissioning of the DR is also reported.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPAB07  
About • paper received ※ 20 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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TUPBB06 Fast Luminosity Monitoring for the SuperKEKB Collider (LumiBelle2 Project) 173
 
  • P. Bambade, S. Di Carlo, D. Jehanno, V. Kubytskyi, C.G. Pang, Y. Peinaud
    LAL, Orsay, France
  • Y. Funakoshi, S. Uehara
    KEK, Ibaraki, Japan
  
  Funding: - MSCA RISE E-JADE project, funded by European Commission grant number 645479 - Toshiko Yuasa France-Japan Particle Physics Laboratory (project A-RD-08)
LumiBelle2 is a fast luminosity monitoring system prepared for SuperKEKB*. It uses sCVD diamond detectors placed in both the electron and positron rings to measure the Bhabha scattering process at vanishing scattering angle. Two types of online luminosity signals are provided, a Train-Integrated-Luminosity at 1 kHz as input to the dithering feedback system used to maintain optimum overlap between the colliding beams in horizontal plane, and Bunch-Integrated-Luminosities at about 1 Hz to check for variations along the bunch trains. Individual beam sizes and offsets can also be determined from collision scanning. The design of LumiBelle2 will be described and its performance during the Phase-2 commissioning of SuperKEKB will be reported.
*First Tests of SuperKEKB Fast Luminosity Monitors During 2018 Phase-2 Commissioning" (WEPAL038) and "Early Phase 2 Results of LumiBelle2 for the SuperKEKB Electron Ring"(THYGBE4) presented at IPAC18 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUPBB06  
About • paper received ※ 24 September 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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WEXBA04 Early Commissioning of the Luminosity Dither System for SuperKEKB 212
 
  • Y. Funakoshi, T. Kawamoto, M. Masuzawa, S. Nakamura, T. Oki, M. Tobiyama, S. Uehara, R. Ueki
    KEK, Ibaraki, Japan
  • P. Bambade, S. Di Carlo, D. Jehanno, C.G. Pang
    LAL, Orsay, France
  • D.G. Brown, A.S. Fisher, M.K. Sullivan
    SLAC, Menlo Park, California, USA
  • D. El Khechen
    CERN, Geneva, Switzerland
  • U. Wienands
    ANL, Argonne, Illinois, USA
  
  SuperKEKB is an electron-positron double ring collider at KEK which aims at a peak luminosity of 8 x 1035 cm-2s-1 by using what is known as the ’nano-beam’ scheme. A luminosity dither system is employed for collision orbit feedback in the horizontal plane. This paper reports a system layout of the dither system and algorithm tests during the SuperKEKB Phase 2 commissioning.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEXBA04  
About • paper received ※ 15 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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WEPAB03 FCC-ee Operation Model, Availability & Performance 269
 
  • F. Zimmermann, A. Apollonio, M. Benedikt, O. Brunner, S. Myers, J. Wenninger
    CERN, Geneva, Switzerland
  • Y. Funakoshi, K. Oide
    KEK, Ibaraki, Japan
  • C. Milardi
    INFN/LNF, Frascati, Italy
  • A. Niemi
    Tampere University of Technology, Tampere, Finland
  • Q. Qin
    IHEP, Beijing, People’s Republic of China
  • J.T. Seeman
    SLAC, Menlo Park, California, USA
  
  Funding: This work was supported by the European Commission under the HORIZON 2020 project ARIES no.~730871.
This document discusses the machine parameters and expected luminosity performance for the proposed future circular lepton collider FCC-ee. Particular emphasis is put on availability, physics run time, and efficiency. Key performance assumptions are compared with the operational experience of several past and present colliders including their injectors - LHC, LEP/LEP-2, PEP-II, KEKB, BEPCII, DAΦNE, SLC and the SPS complex. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEPAB03  
About • paper received ※ 13 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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WEPBB01 Operation of SuperKEKB in Phase 2 286
 
  • Y. Funakoshi, Y. Arimoto, H. Ikeda, T. Ishibashi, N. Ohuchi, S. Terui, X. Wang
    KEK, Ibaraki, Japan
  
  The Phase 2 commissioning of SuperKEKB was performed from March to July 2018. In this report, the operation statistics and the QCS quench issue which we encountered during Phase 2 are described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-WEPBB01  
About • paper received ※ 20 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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THXBA01 Summary on Accelerator Infrastructures and Commissioning 290
 
  • Y. Funakoshi
    KEK, Ibaraki, Japan
  
  In this paper, summary of the woking group on "Accelerator Infrastructures and Commissioning and Operation" is described.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-THXBA01  
About • paper received ※ 29 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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