Author: Tobiyama, M.
Paper Title Page
MOPP028 Longitudinal Bunch-by-Bunch Feedback Systems for SuperKEKB LER 158
 
  • M. Tobiyama, J.W. Flanagan, T. Kobayashi, S. Terui
    KEK, Ibaraki, Japan
  • J.D. Fox
    Stanford University, Stanford, California, USA
 
  Longitudinal bunch-by-bunch feedback systems to suppress coupled bunch instabilities with minimum bunch spacing of 2 ns have been constructed in SuperKEKB LER. Through the grow-damp and excite-damp experiments with several filling patterns and the transient-domain analysis of unstable modes, the behaviors of possible impedance sources have been evaluated. The measured performance of the system, together with the performance of the related systems such as slow phase feedback to the reference RF clock are reported.  
poster icon Poster MOPP028 [0.519 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP028  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPP018 Synchrotron Radiation Monitor for SuperKEKB Damping Ring in Phase-III Operation 331
 
  • H. Ikeda, J.W. Flanagan, H. Fukuma, H. Sugimoto, M. Tobiyama
    KEK, Ibaraki, Japan
 
  The SuperKEKB damping ring (DR) commissioned in March 2019, before main ring (MR) Phase-III operation. The design luminosity of SuperKEKB is 40 times that of KEKB with high current and low emittance. We constructed the DR in order to deliver a low-emittance positron beam. A synchrotron radiation monitor (SRM) was installed for beam diagnostics at the DR. Streak camera and gated camera were used for measurement of the damping time and the beam size. This paper shows the design of DR SRM and the result of the measurement.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP018  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPP030 Betatron Phase Advance Measurements Using the Gated Turn-by-turn Monitors at SuperKEKB 585
 
  • G. Mitsuka, K. Mori, M. Tobiyama
    KEK, Ibaraki, Japan
 
  In the SuperKEKB commissioning Phases 2 (Feb.-Jul., 2018) and 3 (from Mar. 2019), the betatron phase advances between adjacent beam position monitors have been measured using a total of 138 gated turn-by-turn monitors. A fast RF gating of the monitors enables turn-by-turn beam position detections by focusing only on an artificially-excited non-colliding bunch, while leaving colliding bunches unaffected. Betatron phase advances measured by the gated turn-by-turn monitors and accordingly obtained betatron functions were consistent with the closed orbit measurements. High signal-to-noise ratio were achieved by advanced signal extraction methods such as NAFF, SVD, and independent component analysis.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP030  
About • paper received ※ 03 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)