The ATLAS TileCal Read-Out Drivers Signal Reconstruction

TileCal is the hadronic calorimeter of the ATLAS experiment at the LHC collider at CERN. The Read-Out Drivers (ROD) are the core of the off-detector electronics. The main components of the RODs are the Digital Signal Processor (DSP) placed on the Processing Unit (PU) dautherboards. This paper describes the DSP code and its performance with calibration and real data. The code is divided into two different parts: the first part contains the core functionalities and the second one the reconstruction algorithms. The core acts as an operating system and it controls the configuration, the data reception, transmission, online monitoring and the synchronization between front-end data and the Trigger information. The reconstruction algorithms implemented on the DSP are the Optimal Filtering (OF), Muon Tagging (MTag) and Total Transverse Energy (ET) calculation. The OF algorithm reconstructs the deposited energy and the arrival time of the data on every calorimeter cell within a front-end module. This reconstructed energy is used by the MTag algorithm to tag low transverse momentum muons that may escape the ATLAS muon spectrometer Level 1 trigger whereas the ET algorithm computes the total transverse energy and the projection on X and Y for the entire module that will be used by the Level 2 trigger system. The DSP code performance is being validated with comparisons with offline reconstruction. The DSP performance is evaluated using cali bration data from Charge Injection System.