Author: Zhou, D.
Paper Title Page
TUOAB04 Optics Corrections including IP Local Coupling at SuperKEKB 63
 
  • A. Morita, H. Koiso, K. Ohmi, Y. Ohnishi, H. Sugimoto, D. Zhou
    KEK, Ibaraki, Japan
 
  The phase-2 commissioning of the SuperKEKB accelerator with the interaction point(IP) has been performed from March 19 to July 17. In the collision operation during this commissioning, the vertical beta function at the IP was squeezed down to 3mm. In order to achieve such low beta collision operation, many optics corrections were performed. We present the result of those optics measurement and correction.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-eeFACT2018-TUOAB04  
About • paper received ※ 12 October 2018       paper accepted ※ 19 February 2019       issue date ※ 21 April 2019  
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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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