Signal Reconstruction of the Atlas Hadronic Tile Calorimeter: Implementation and Validation

TileCal, the central hadronic section of the ATLAS Calorimeter, is a sampling calorimeter consisting of steel and scitntillating tiles. The TileCal front-end electronics allows to measures the signals produced by about 10000 photo-multipliers measuring energies ranging from about 30 MeV to about 2TeV . The read-out system is responsible to reconstruct the data in real-time fulfilling the tight time constraint imposed by the ATLAS first level trigger rate (100 KHz). The main component of the read-out system is the Digital Signal Processor (DSP) which, using the Optimal Filtering technique, allows to compute for each channel the signal amplitude, time and quality factor at the required high rate. After a short overview of the TileCal system we will discuss the implementation of Optimal Filtering signal reconstruction highlighting the constraints imposed by the use of the DSP. We will than report results on the validation of the implementation of the DSP signal reconstruction and the overall signal reconstruction performances measured both in calibration, single beam and collision events will be presented.