Emittance Preservation at the LHC

The Large Hadron Collider (LHC) at CERN is a high energy storage ring that provides proton and heavy ion collisions to study fundamental particle processes. The luminosity production is tightly linked to emittance preservation in the accelerator. During the 2012 LHC proton run about 30 % of the potential luminosity performance was lost through the different phases of the LHC cycle, mainly due to blow-up of the transverse emittance. At the LHC design stage the total allowed emittance increase through the cycle was set to 7 %. A breakdown of the growth through the various phases in the LHC cycle is given, as well as a comparison with the data from the LHC experiments for the transverse beam size. In 2012 a number of possible causes and solutions of emittance blow-up in the LHC have been studied. Among the sources are intra-beam scattering and 50 Hz noise. A possible remedy for some of the growth is higher transverse damper gain. The results of the investigations are summarized in this thesis. Measuring the emittance growth is a difficult task with high intensity beams and changing energies. Accuracy and limitations of the LHC transverse profile monitors will be discussed. An outlook for future LHC upgrade scenarios with low emittance beams will be given.