  The reconstruction of non pointing photons is a key feature for studying
gauge mediated supersymmetry breaking (GMSB) models at the LHC. In this article
the angular resolution of the ATLAS electromagnetic calorimeter is
characterized from a detailed simulation of the detector. Resulting
performances are used to reconstruct GMSB events with a fast simulation
program, taking into account reconstruction effects. Finally, the sensitivity
to extract the sparticles masses and the lightest neutralino lifetime is
estimated.
