Novel Concepts for Optimization of the CERN Large Hadron Collider Injection Lines.

The Large Hadron Collider (LHC) is presently the particle accelerator with the highest center of mass energy in the world and is for that reason the most promising instrument for particle physics discoveries in the near future. The transfer lines TI2 and TI8 which transfer the beam from the last pre-accelerator, the Super Proton Synchrotron (SPS), to the LHC are with a total length of about 6 km the longest ones in the world, which makes it necessary to do optics matching with high precision. Tests between 2004 and 2008 revealed several, previousely unpredicted, effects in these lines: An assymetry in betatron phase between the two transverse planes, a dispersion mismatch at the injection point from the transfer lines to the LHC and unexpectedly strong transverse coupling at the same location. In this thesis, we introduce the methods and tools that we developed to investigate these discrepancies. We describe the analysis of the available data, measurements of the transfer line optics and the calculation of optics corrections. Further we show that the optics mismatch can be explained from a sextupolar field component in the injection main bends, which we deduced from beam measurements and later was confirmed by numerical magnet simulations. Finally, we describe the measures taken to improve the underlaying numerical models and demonstrate the very good measurement-model agreement for kick response measurements and dispersion up to second order, which guarantees an excellent beam quality in the LHC.