Longitudinal Beam Loss Distribution along the LHC Ring

For the design and calibration of the LHC beam loss monitoring (BLM) system it is essential to have good predictions of the expected longitudinal loss distributions. For this purpose, a complete and detailed aperture model of the LHC arc and dispersion suppressor (DS) was compiled and applied to the tracking of halo particles originating from the betatron cleaning insertion for proton and ion beams. The positions of all beam pipe bellows are included in the model as well. Therefore, it is possible to investigate the loss pattern due to misalignment effects, in addition to steady beam losses (beam halo, beam-beam and beam-rest gas interactions) and orbit errors. For proton beams the model was applied within the tracking code MAD-X [1]. Resulting loss maps are presented in this paper. The simulation for the ion beam halo is presented in [8]. The model served to identify critical loss positions. The implication of both simulations for the BLM design are discussed.