Impact of linear imperfections in the high luminosity LHC separation dipole magnets

Magnetic field measurements have been performed after fabrication of new separation dipoles for the low beta-star insertion regions of the High Luminosity LHC project*. In this paper, the effect of the linear imperfections of these magnets on coupling, beam size and beta-beating are evaluated using MAD-X simulations. The results indicate that the impact of normal-oriented quadrupole errors are small and easily correctable, while for skew-oriented quadrupole imperfections corrections require a significant fraction of the arc skew quadrupoles strength. Subsequent simulation studies were therefore performed to devise potential mitigation strategies, the results of which are also reported here.