Optics solutions in IR8 for Ring-1 and Ring-2 of the LHC Version 6.0

In version 6 of the LHC lattice the pairs of standard arc and additional trim quadrupoles in the dispersion suppressor (DS) are replaced by individual units. The individual powering of these units provides additional flexibility in the DS. As a result of this modification the quadrupole positions and maximum strength changed, requiring an update of the optics in the insertions. We took advantage of this redesign and incorporated new requirements on the injection optics leading to different phase advances over the IR as compared to version 5 of the LHC lattice. The optics is calculated for both rings and its flexibility investigated. The presented solutions are antisymmetric with respect to the IP (alpha* = 0.0), obey the injection constraints (90 degree vertical phase between injection kicker and absorber), avoid too low gradients at injection energy (450GeV), minimise the beam size during injection and lead to a smooth change of the quadrupole gradients during the transition from injection to collision optics.