The ATLAS Tile Calorimeter performance at LHC in pp collisions at 7 TeV

The Tile Calorimeter (TileCal), the central section of the % hadronic calorimeter of the ATLAS % experiment, is a key detector component % to detect hadrons, jets and taus and to % measure the missing transverse energy. % Due to the very good muon signal to noise % ratio it assists the muon % spectrometer in the identification and reconstruction % of muons. ewline %%%% TileCal is built of steel and % scintillating tiles coupled to optical fibers % and read out by photomultipliers. The calorimeter % is equipped with systems that allow to % monitor and to calibrate each stage of the % read-out system exploiting different signal % sources: laser light, charge injection and a radioactive % source. It also uses the Minimum Bias % current integrated over thousands % of LHC collisions to monitor the response % stability and the LHC luminosity.\ %%%%% The performance of the calorimeter has % been measured and monitored using % calibration data, random triggered data, cosmic % muons, splash events and more importantly % LHC collision events. The results presented % assess the absolute energy scale calibration % precision, the energy and timing uniformity and % the synchronization precision. The results % demonstrate a very good understanding of the % performance of the Tile Calorimeter that is well % within the design expectations. %