Pulse shapes for signal reconstruction in the ATLAS Tile Calorimeter

摘要

The Tile Calorimeter for the ATLAS experimentat the CERN Large Hadron Collider (LHC) is ready for datataking with the proton-proton collisions. The Tile Calorimeteris a sampling calorimeter with iron absorber and scintillatorsas active medium. The scintillators are read out by wavelengthshifting fibers and photomultiplier tubes. The analogue signalsfrom the PMTs are digitized by sampling the PMT signals every25ns. For each interesting event selected by the ATLAS trigger,the Tile Calorimeter reads out seven consecutive samples, thuscovering a time window of 175ns. The seven consecutive samplesare combined by the electronics in a remote counting room, ata rate of up to 100kHz, to compute the pulse amplitudes andtheir position in time. These quantities are required for energyreconstruction. A solid understanding of the pulse shapes in thecalorimeter is required for an accurate energy reconstruction.Systematic studies of the pulse shapes in the ATLAS TileCalorimeter have been performed by exposing modules of thecalorimeter to single pions in test beam runs. These studiesare presented and the implications for energy reconstruction aregiven.