Iterative local Chi2 alignment algorithm for the ATLAS Pixel detector

The existing local chi2 alignment approach for the ATLAS SCT detector was extended to the alignment of the ATLAS Pixel detector. This approach is linear, aligns modules separately, and uses distance of closest approach residuals and iterations. The derivation and underlying concepts of the approach are presented. To show the feasibility of the approach for Pixel modules, a simplified, stand-alone track simulation, together with the alignment algorithm, was developed with the ROOT analysis software package. The Pixel alignment software was integrated into Athena, the ATLAS software framework. First results and the achievable accuracy for this approach with a simulated dataset are presented.