The aim of the thesis is the study of the electromagnetic showers and neutral mesons in the ICARUS T600 Liquid Argon Time Projection Chamber. To accurately reconstruct energy of electromagnetic showers, different corrections to the collected charge are needed. In this thesis the author calibrated the energy reconstruction with a set of corrections, most of which are not present in the official ICARUS reconstruction software. For this goal, the simulation package FLUKA was extensively used in order to study the ionization quenching and
the shower containment in the detector. As a result the reconstructed invariant ⇡0 masses are distributed compactly (" = 12 MeV/c2) with
a best value equal to 134.5 ± 1.5 ± 4.2 MeV/c2. Moreover, other results on low energy electromagnetic showers in Liquid Argon were found which include the longitudinal profile parametrization, the conversion
distance measurement and the ionization losses for 1 and 2 m.i.p. particles. This latest point is interesting for the e CC events selection from ⌫μ NC background.