Status of the ATLAS Liquid Argon Calorimeter and Its Performance after One Year of LHC Operation

The ATLAS experiment is designed to study the proton-proton collisions produced at the LHC with a centre-of-mass energy of 14 TeV. Liquid Argon (LAr) sampling calorimeters are used in ATLAS for all electromagnetic calorimetry covering the pseudorapidity region |η| <3.2, as well as for hadronic calorimetry from η = 1.4 to η = 4.8. An overview of the system is shown as well as a discussion of its operation and performance at √s=900 GeV and 7 TeV since the start of LHC running. The latest status of the detector as well as problems and solutions addressed during the last years are also discussed.