The FEDRA—Framework for emulsion data reconstruction and analysis in the OPERA experiment

OPERA is a massive lead/emulsion target for a long-baseline neutrino oscillation search. More than 90% of the useful experimental data in OPERA will be produced by the scanning of emulsion plates with the automatic microscopes. The main goal of the data processing in OPERA will be the search, analysis and identification of primary and secondary vertices produced by neutrino in lead-emulsion target. lume of middle- and high-level data to be analysed and stored is expected to be of the order of several Gb per event. The storage, calibration, reconstruction, analysis and visualization of this data is the task of FEDRA system written in C ++ and based on ROOT framework. The system is now actively used for processing of test beams and simulation data. Several interesting algorithmic solutions permits us to make effective code for fast pattern recognition in heavy signal/noise conditions. The system consists of the storage part, intercalibration and segments linking part, track finding and fitting, vertex finding and fitting and kinematical analysis parts. Kalman Filtering technique is used for tracks & vertex fitting. ROOT-based event display is used for interactive analysis of the special events.