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Farvacque, L.

Paper Title Page
MPPP021 Evolution of the Machine Impedance following the ESRF Upgrade to Low-Gap NEG Coated Aluminium Chambers 1712
 
  • T.F. Günzel, L. Farvacque, T. Perron, J.-L. Revol
    ESRF, Grenoble
 
  The installation of 5 meter-long, 8 mm vertical aperture insertion device (ID) aluminum chambers coated in house with non evaporable getter material is progressing at a rate of one chamber per shutdown. The evolution of the impedance with associated consequences on instability thresholds, following the installation of a number of low aperture insertion device chambers will be reported. In particular the impedance measurement using the local bump method allowed the identification and the replacement of the chambers of highest impedance. Correlation with the evolution of the single bunch instability thresholds and the theoretical prediction will be discussed. It could be observed that change in vertical aperture has a sensible effect on the single bunch horizontal threshold.  
WOAC010 Measurement of Linear Lattice Functions in the ESRF Storage Ring Using Turn-by-Turn Data 698
 
  • Y. Papaphilippou, L. Farvacque, J.-L. Revol, V. Serriere
    ESRF, Grenoble
  • S.-L. Bailey
    The College of William and Mary, Williamsburg
 
  A model-independent method to measure linear optics functions has been tested in turn-by-turn data from the ESRF storage ring. This method does not necessitate neither the knowledge of the model nor magnetic element manipulation. It uses only the positions measured in consecutive BPMs of betatron oscillations issued by small transverse kicks. The phase advances and tunes necessary to construct the transfer matrices are issued by refined Fourier analysis. The method's precision is compared with classical methods such as response matrix analysis and beam matrix construction.  
RPAE027 Linear Optics Measurements in the ESRF Booster 1973
 
  • Y. Papaphilippou, L. Farvacque, E. Plouviez
    ESRF, Grenoble
  • A. Mostacci, A. Patriarca
    Rome University La Sapienza, Roma
 
  A series of experiments has been conducted in the ESRF booster in order to measure its linear optics. A steerer response matrix was developed and used to optimise the orbit correction at injection by developing a refined model. This matrix was also used to measure the beta functions along the accelerating cycle and the steerer calibration. Dispersion was also measured with classical RF scans and compared to theory. Finally, chromaticity measurements were performed for different sextupole settings enabling their calibration and optimisation.  
RPAE028 Lattice Upgrade Options for the ESRF Storage Ring 2047
 
  • Y. Papaphilippou, P. Elleaume, L. Farvacque, A. Ropert
    ESRF, Grenoble
 
  Several scenarios of lattice upgrade for the ESRF storage ring are under study. In order to minimise the cost, their design is based on the length constraints of the existing tunnel with the ID beamlines kept in place. The goal is to shrink the emittance in order to increase the undulator brilliance. The two main options are a double bend achromat structure with non-uniform field dipoles and a triple bend achromat lattice. The two scenarios are detailed and compared with respect to their linear optics solutions, correction of chromatic effects and non-linear dynamics. An attempt to reveal the horizontal effective emittance dependence on important design parameters, such as optics functions maxima, chromaticity and dynamic aperture, is also undertaken. Technological challenges concerning magnet design with small physical aperture in a reduced space are also addressed.