EUROTeV-Report-2008-017 SIMULATION STUDIES OF CORRELATED MISALIGNMENTS IN THE ILC MAIN LINAC AND THE INFLUENCE OF GROUND MOTION

Component misalignments are an important source of emittance dilution in the main linac of the International Linear Collider (ILC). The impact of static uncorrelated alignment errors has been widely studied with various simulation codes and several beam based alignment algorithms. For a realistic scenario one has to take into account that the survey and alignment process will introduce correlations between the component errors. In the present paper we study the performance of the Dispersion Matched Steering (DMS) technique for the case of such correlated misalignments. Different models for the correlations are investigated including a model characteristic of the alignment and survey technique envisaged for the ILC [1] which has been implemented into the Merlin C++ library [2] based package ILCDFS [3]. In addition to the initial static errors, dynamic errors due to ground motion will produce an emittance growth with time. For this case we have also investigated the stability of DMS tuning over time