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Nagaoka, R.

Paper Title Page
WEPB05 Streak Camera Measurements of the SOLEIL Bunch Length 241
 
  • M. Labat, L. Cassinari, M.-E. Couprie, R. Nagaoka, D. Pédeau
    SOLEIL, Gif-sur-Yvette
 
  A double sweep streak camera (C5680, Hamamatsu) has been installed on the French third generation light source SOLEIL. The visible radiation of the diagnostics beam-line is used to study the longitudinal profile of the stored electron bunches. We report on the commissioning of the streak camera, as well as on its first uses. Measurements of single-bunch length as a function of various machine parameters such as RF cavity voltage and frequency, and beam current with a few picoseconds resolution are reported, and interpreted in terms of vacuum chamber impedance and beam stability.  
WEPC04 Transverse Feedback Development at SOLEIL 316
 
  • R. Nagaoka, L. Cassinari, J.-C. Denard, J.-M. Filhol, N. Hubert, M.-P. Level, P. Marchand, C. Mariette, F. Ribeiro, R. Sreedharan
    SOLEIL, Gif-sur-Yvette
  • K. Kobayashi, T. Nakamura
    JASRI/SPring-8, Hyogo-ken
 
  The SOLEIL ring is planned to operate in both multibunch and high current per bunch modes. However, the small vertical chamber aperture around the SOLEIL ring enhances the transverse impedance both in its resistive-wall and broadband content, resulting in instabilities that appear at relatively low current compared to the desired values. A decision was therefore taken to install a digital bunch-by-bunch feedback system, with an aim to make it operational from the beginning of the user operation. The system implemented comprises components developed elsewhere, particularly the FPGA processor of Spring-8, chosen among different possible solutions. Using a BPM and a stripline in the diagonal mode, a single unit of the FPGA processor board has shown to successfully suppress resistive-wall and ion induced instabilities in either one or both transverse planes up to 300 mA. The paper discusses the system characteristics including striplines whose shunt impedance was maximised by keeping the coupling impedance small*, the obtained performance as well as future extensions to overcome the encountered limitations.

* C. Mariette ID1209

 
WEPC16 Excitation Striplines for SOLEIL Fast Transverse Feedback 343
 
  • C. Mariette, J.-C. Denard, R. Nagaoka
    SOLEIL, Gif-sur-Yvette
 
  SOLEIL, the French third generation light source, is equipped with excitation striplines for a tune monitor and for the (bunch-by-bunch) Fast Transverse Feedback* that has been recently implemented. A careful design of the striplines and their vacuum feedthroughs was aimed at maximizing the effectiveness of the excitation power via high shunt impedances, and minimizing the power taken from the beam via low parasitic mode losses. Three stripline kickers have been developed for these applications. We report on their design using RADIA and GdfidL simulation codes, on the fabrication of the striplines, and on the experimental results with beam.

* R. Nagaoka: Transverse Feedback Development at SOLEIL. ID 1257