Momentum Cleaning in the CERN LHC

This paper describes the optimization of the optics and the collimator geometry for the momentum cleaning insertion of the LHC. To collimate the off-momentum secondary halo without disturbing the circ ulating beam, the normalized dispersion in IR3 is made as large as in the arcs. The jaw locations and orientations are numerically optimized to reduce the momentum-dependent halo amplitude. The second ary halo is kept within the available aperture for momentum deviations up to 0.44%, where the horizontal aperture is 4$\sigma\, compared to 12$\sigma\ on-momentum.