Physical Review Special Topics. Accelerators and Beams (Jul 2004)

Synchrobetatron stop bands due to a single crab cavity

  • Georg H. Hoffstaetter,
  • Alexander W. Chao

DOI
https://doi.org/10.1103/PhysRevSTAB.7.071002
Journal volume & issue
Vol. 7, no. 7
p. 071002

Abstract

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We analyze the stop band due to crab cavities for horizontal tunes that are either close to integers or close to half integers. The latter case is relevant for today’s electron/positron colliders. We compare this stop band to that created by dispersion in an accelerating cavity and show that a single typical crab cavity creates larger stop bands than a typical dispersion at an accelerating cavity. We furthermore analyze whether it is beneficial to place the crab cavity at a position where the dispersion and its slope vanish. We find that this choice is worth while if the horizontal tune is close to a half integer, but not if it is close to an integer. Furthermore we find that stop bands can be avoided when the horizontal tune is located at a favorable side of the integer or the half integer. While we are here concerned with the installation of a single crab cavity in a storage ring, we show that the stop bands can be weakened, although not eliminated, significantly when two crab cavities per ring are chosen suitably.