HI-LUMI LHC COLLIMATION STUDIES WITH MERLIN CODE

The collimationsystem is key to the successful operation of the LHC. Measurements and simulations of the previous run at 4 TeV have shown that the system is ready for the next step, running at 7 TeV, but at the same time some sensitive cleaning locations have been identified. In particular the dispersion suppressors downstream of the betatroncleaning region in IR7 are sensitive to single diffractive scattered protons from the collimatorjaws. These particles can lead to magnet quenching. The MERLINC++ library has been developed to exploit the functionality of an object oriented code, with improved collective effects and scattering routines. New single diffractive and elastic scattering routines, based on a fit of existing experimental data with the Regge theoryof soft interactions of high energy scattering, is implemented in MERLIN. In this paper we present the impact of the new single diffractive scattering physics on the cleaning inefficiency of the LHC collimationsystem for the Achromatic TelescopeSqueezing (ATS) PreSqueeze optics scheme, for the HL-LHC project. The results are compared with the same loss map calculated using a SixTrack+K2 like scattering routine.