ATLAS liquid argon barrel calorimeter performance in test-beams

During the combined test-beam in summer 2004 a slice of the ATLAS barrel detector-including all detector sub-systems from the inner tracker, the calorimetry to the muon system-was exposed to particle beams (electrons, pions, photons, muons) with different energies (1-350 GeV). The aim was to study the combined performance of the different detector sub-systems in ATLAS-like conditions. We will present studies with different amounts of material in front of the calorimeter, representing various regions in the ATLAS detector, performance results from the electromagnetic calorimetry, including energy reconstruction, uniformity, resolution and linearity. The performance in the combined ATLAS like set-up will be compared to the one obtained in stand-alone test-beams