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FCC-ee top-up injection

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FCC-ee top-up injection
Zoom Meeting ID
66156014911
Host
Yann Dutheil
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participants : H. Bartosik, C. Carli, Y. Dutheil, G. Nigrelli, T. Mori, P.Raimondi, K. Skoufaris, S. Yue

 

  • BSC and impact on the bump amplitude for conventional injection
    • Stay-clear definition is linear sum of beta and disp primary cut, may become larger with errors
    • Need to add the distance in stay clear- distance
    • Question of the local bump during injection at the collimator,
      • could we instead place such collimator closer to the septum
      • There will anyway be an absorber there and can be adjustable
      • Important to estimate the number of particle that would hit this collimator
    • An increase to the bump amplitude should be established to account for margin, which should be coming from collimation
      • Also errors should be considered as it may diverge considerably
      • Non linearities for instance through non-linear dispersion can be obtained with twiss
    • Ttbar mode
      • Using a guess on the momentum cut, final numbers need collimation input
      • Question of keeping bump height constant for every mode, take the max
      • Or keep a lower bump at Z-mode and use the 4 dipoles used for dispersion to adjust the closed orbit. And we don't need to use movable septum
    • Should be considering pi bump and minimize the bump amplitude
      • Pi bump has optics constraints, and other concerns
      • Other concerns about non closure are in vertical due to tilt or optics. Compensated with skew quads in the bump at ESRF
      • Still need to see the implication of 2 Vs 4 kickers
      • Pi bump also causes non-closed dispersion bump, which is significant at ESRF and would need to be considered carefully
      • The consideration on the bump amplitude shouldn't only be about local closure but also back-propagate from the IP
    • Make an updated sketch about bump height and share this with the working group for discussion
    • Important to establish a TODO list, or priority list
    • Question of the failure cases
  • What number to share, and highlight the physics that is included
    • From Giulia With bare lattice it is 100%, with BB 90% and with collimation reach 87%
    • With errors and beam-beam, efficiencies are somewhat lowers but this is a work in progress
    • Kyriacos is also working on some aspects which should be discussed
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