Analysis of data obtained in combined tests of an electromagnetic liquid argon calorimeter with a hadronic scintillating tile calorimeter

The future ATLAS experiment at LHC-CERN will include in the central region a calorimeter system composed of two separate units, the Liquid Argon (LAr) electromagnetic calorimeter with hermetic accordion geometry and a scintillating tile hadronic calorimeter, using iron as absorber, in which the tile are placed perpendicular to the colliding beams. This system must be able to identify electrons, photons and jets and to reconstruct their energies and angles as well as to measure the missing transverse energy in the events. Three algorithm, employed to reconstruct the hadron energy, are described. A special interest was devoted to the study of energy deposition in various depth samples of the test calorimeter stack to obtain the longitudinal and transverse shower shapes. The longitudinal profiles in the electromagnetic and hadronic calorimeters for pions with different energies were compared with the Monte Carlo predictions. The GEANT simulations reproduces reasonably well the shape of the data in hadronic compartment, while a difference is observed in the electromagnetic part. We intend to study in more details the problems connected with the energy leakage which cause a degradation of the energy resolution as well as tails in the energy distributions