Alignment of the ZEUS micro-vertex detector using cosmic tracks

ZEUS Micro-Vertex Detector (MVD) was installed in ZEUS after the HERA upgrade in 2000. MVD is a precise position detector consisting of 712 single-sided silicon strip detectors. The alignment of the barrel MVD has been performed in units of ladders using cosmic tracks. The procedure used is an iterative χ2χ2 minimization, where χ2χ2 is defined locally for each ladder. The procedure is numerically stable since it only requires an inversion of 30 6×66×6 matrices and reasonably fast in spite of the iterative approach.