ATLAS DETECTOR OVERVIEW (OPERATION,EXPERIENCE, PERFORMANCE)

ATLAS is a general-purpose detector located at one of the 4 interaction points of the LHC at the CERN laboratory near Geneva, Switzerland. In 2010 and since March 2011 LHC is colliding proton beams at the unprecedented centre of mass energy of 7 TeV. The last month of 2010 operation was dedicated to Pb‐ion collisions at a centre of mass energy of 2.76 TeV per nucleon pair. A challenging task of the previous months was to cope with the increasing event rates due to the increasing luminosity delivered by the LHC collider. A survey of the main ATLAS sub-detector systems, their operating conditions and the performance with colliding beams will be presented in this talk. The operation and results obtained from the data collected so far demonstrate that the detector is robust and functioning very well.