Performance of the ATLAS Calorimeters using Cosmic Muons

The ATLAS calorimeter provides precision measurements of electrons, photons, jets and missing transverse energy produced in the LHC proton-proton collisions. High granularity liquid-argon electromagnetic and hadronic sampling calorimeters are used. An iron-scintillator hadronic calorimeter surrounds the liquid-argon detectors. Results assessing the calorimeter performance obtained using cosmic ray muons are presented. The non-uniformity of the barrel electromagnetic calorimeter response is consistent at the percent level with the simulated response. The response uniformity of the hadronic calorimeter compartments is at the level of 4%. The determination of the global energy scale was performed in the hadronic calorimeter with an uncertainty of ±4%.