The PHOS (PHOton Spectrometer), is a high resolution electromagnetic calorimeter consisting of 17920 detection channels based on lead-tungstate crystals, PbWO4 (or PWO). It is positioned on the bottom of ALICE set-up at a distance 460 cm from the interaction point. The PHOS will cover the pseudorapidity range –0.12 < eta < 0.12 and 100^o in azimuthal angle. The PHOS is mainly dedicated to the search for electromagnetic signals from the QGP in nucleus-nucleus interactions at high energies.