Commissioning of the ATLAS Tile Calorimeter with Cosmic Ray and Single Beam Data

The commissioning of the ATLAS detector at the LHC has been the focus of an extensive program over several years, in preparation for the first LHC beams in 2008. We present a summary of cosmic ray and single beam commissioning results with the ATLAS hadronic Tile Calorimeter (TileCal). The emphasis will be on understanding the reconstruction of calorimeter data at each stage, from raw ADC counts, cell energy and timing, and high-level physics objects like clusters. Calibration of energy and timing is validated with cosmic and single beam data. Electronic noise at the cell level is studied, and the performance of calorimeter clustering is investigated. We discuss in detail the "Topological Clustering" technique which is one of the standard clustering algorithms in ATLAS.