The ATLAS Liquid Argon Calorimeter: Overview and Performance

The LHC is delivering collision data since Nov. of 2009 and create the new world center of mass energy record of 7 TeV. ATLAS experiment at LHC has been collected more than 1 nb-1 collision data till the end of April 2010. The ATLAS Liquid Argon (LAr) Calorimeter, which is operational since August 2006, has been carefully commissioned and checked using these collision data, beam data and previous taken cosimics data. This paper will give an overview of the ATLAS LAr calorimeter hardware status and performance up to the latest 7 TeV collision data. Results on the LAr calorimeters high voltage, LAr temperature, purity, electronics stability, timing alignments, and early collision performance results are shown here, indicate that ATLAS LAr calorimeters are well commissioned and show good performance for the physics at LHC era, at least for the first data stage.