The TileCal energy reconstruction for collision data using the matched filter

The Tile Barrel Calorimeter (TileCal) is the central section of the hadronic calorimeter of ATLAS at LHC. It comprises more than 10,000 readout channels. The energy deposited in each channel is read out and the analog pulse is conditioned by a shaper circuit. The signal energy is estimated by reconstructing the amplitude of the digitized pulse sampled every 25 ns. This work presents the performance of an alternative algorithm for TileCal energy reconstruction, namely the TileCal Matched Filter (MF). The performance of the MF method is compared to the currently implemented algorithm (OF2) using collision data acquired in 2010 during LHC operation period. The results showed that the MF presents smaller error estimation (variance) than the OF2 method. In addition to that, the methods showed to be highly correlated with each other for high SNR signals. Preliminary results using special ATLAS collision data taken later in 2012, for which LHC operated at 25 ns bunch spacing and ATLAS observed an increase of the pile-up effect, are also provided.