Simulating the LHC collimation system with the accelerator physics library MERLIN, and loss map results

We present large scale simulations of the LHC collimation system using the MERLIN code for calculations of loss maps, currently using up to 1:5 10 9 halo particles. In the dispersion suppressors following the collimation regions, protons that have undergone diffractive interactions can be lost into the cold magnets. This causes radiation damage and could possibly cause a magnet quench in the future with higher stored beam energies. In order to correctly simulate the loss rates in these regions, a high statistics physics simulation must be created that includes both accurate beam physics, and an accurate description of the scattering of a 7 TeV proton in bulk materials. The current version includes the ability to simulate new possible materials for upgraded collimators, and advances to beam-collimator interactions, including proton-nucleus interactions using the Donnachie-Landshoff Regge-Pomeron scattering model. Magnet alignment and field errors are included, in addition to collimator jaw alignment errors, and their effects on the beam losses are systematically estimated. Collimator wakefield simulations are now fully parallel via MPI, and many other speed enhancements have been made.