Author: Piminov, P.A.
Paper Title Page
WEPEA049 Analysis of the Non-linear Fringe Effects of Large Aperture Triplets for the HL LHC Project 2615
  • A.V. Bogomyagkov, E.B. Levichev, P.A. Piminov
    BINP SB RAS, Novosibirsk, Russia
  • A. Chancé, B. Dalena, J. Payet
    CEA/IRFU, Gif-sur-Yvette, France
  • R. De Maria, S.D. Fartoukh, M. Giovannozzi
    CERN, Geneva, Switzerland
  Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
The HL-LHC project relies on large aperture quadrupoles which are compatible with the very large beam sizes in the inner triplets resulting from the strong reduction of β*. As a result the beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. The spatial extension of these fringe fields increases as well more or less linearly with the coil aperture, which is an additional motivation to analyse this aspect in detail in the framework of the High Luminosity LHC design study. This paper will quantify this effect both by direct analytical estimates using first order Hamiltonian perturbation theory, and via numerical studies thanks to the dedicated implementation of a fringe field symplectic integrator in SixTrack.