Off-momentum collimation and cleaning in the energy ramp in the LHC

This Master thesis work has been carried out at CERN in the framework of the LHC (Large Hadron Collider) Collimation project. The LHC is a two-beam proton collider, built to handle a stored energy of 360MJ for each beam. Since the energy deposition from particle losses could quench the superconducting magnets, a system of collimators has been installed in two cleaning insertions in the ring and in the experimental areas. The achievable LHC beam intensity is directly coupled to the beam loss rate and, consequently, to the cleaning efficiency of the collimation system. This study analyses the collimation cleaning performance in different scenarios inside the accelerator. First, simulations are performed of the transverse losses in the LHC collimation system during the acceleration process. The results are compared with data taken during a dedicated session at the LHC machine. Simulations are also performed to predict the collimation efficiency during future operation at higher energy. Furthermore, an investigation of the effect of losses of protons, that have slowly lost energy through synchrotron radiation, is carried out. These protons eventually hit the momentum collimators, where the impact coordinates can be used as a starting point for future studies of radiation damage to nearby warm magnets.