The ATLAS liquid argon calorimeter : test beam, installation and commissioning

The ATLAS liquid argon (LAr) calorimeter system consists of an electromagnetic barrel calorimeter and two endcaps with electromagnetic, hadronic and forward calorimeters. The construction of the full calorimeter system is completed since mid-2004. Since then, the calorimeters have been installed in the ATLAS cavern. The electronics read-out system is being installed and tested for both the barrel and endcaps. Since 2006, cosmic muon data involving a progressively larger fraction of the detector has been collected, allowing to test the electronic readout system, and check calorimeter response across the calorimeter. Previous test-beam studies and large scale simulation are also key ingredients to prepare for collider data taking in 2008.