Signal reconstruction in a high rate environment for scintillator calorimeters

We present an algorithm to reconstruct online the energy in the TiCal detector of ATLAS. The algorithm consists in weighted sums of the digital samples of the photomultiplier signal. The weights are calculated to reconstruct the desired parameters of the signal while minimizing the noise impact on the resolution. The algorithm has been satisfactorily tested in two types of data, data obtained with a charge injection calibration system and real physics data. The results are promising given significant improvements specially when the signal to noise ratio is small as it has been designed for