Software alignment of the LHCb outer tracker chambers [Elektronische Ressource] / presented by Marc Deissenroth

DISSERTATIONsubmitted to theCombined Faculties for the Natural Sciences and Mathematicsof the Ruperto-Carola University of Heidelberg, Germanyfor the degree ofdoctor rerum naturaliumpresented byDipl.-Phys. Marc Deissenrothborn in Salzkotten, GermanystOral examination: April 21 , 2010Software Alignment ofthe LHCb Outer Tracker ChambersReferees: Prof. Dr. Ulrich UwerProf. Dr. Hans-Christian Schultz-CoulonAbstractThis work presents an alignment algorithm that was developed to precisely deter-mine the positions of the LHCb Outer Tracker detector elements. The algorithmis based on the reconstruction of tracks and exploits that misalignments of thedetector change the residual between a measured hit and the reconstructed track.It considers di erent levels of granularities of the Outer Tracker geometry and fullyaccounts for correlations of all elements which are imposed by particle trajectories.In extensive tests, simulated shifts and rotations for di erent levels of the detectorgranularity have been used as input to the track reconstruction and alignmentprocedure. With about 260 000 tracks the misalignments are recovered with astatistical precision ofO(10 100m) for the translational degrees of freedom and2 1ofO(10 10 mrad) for rotations. A study has been performed to determinethe impact of Outer Tracker misalignments on the performance of the track re-construction algorithms.