Identified Particle Spectra with the ALICE ITS in stand-alone mode

ALICE (A Large Ion Collider Experiment) is one of the experiments at the Large Hadron Collider (LHC) and it is dedicated to heavy-ion physics, with the aim of explorating matter in extreme condition of pressure and temperature. In this thesis work the transverse momentum spectra of pions, kaons and protons have been analyzed for collisions with a center of mass energy og 900 Gev, 2.76 TeV and 7 TeV through the informations provided by the Inner Tracking System, one of the ALICE subdetectors. In the first chapter there's a brief description of the physics of Quark Gluon Plasma. The second chapter is dedicated to the ALICE layout. In the third chapter the tracking algorithm, event selection and analysis method are presented. The fourth chapter show how it is possible to extract the spectra with an alternative procedure which makes use of the ROOT class TFractionFitter. The last chapter shows how to correct the spectra to get the final results, which are then compared to the ones coming from previous experiments.