Abstract
The shower shape of n, 
, p, 
, K+, π+ and photons, generated by JPCIAE code for 5.5 TeV/A208Pb+208Pb collisions, incident on the ALICE photon spectrometer (PHOS), is analyzed with the principal component analysis (PCA) method. The efficiency dependence of purity for the photon discrimination is simulated for the deposited energy ranges 0.5–2 GeV, 2–10 GeV, 10–50 GeV and 50–100 GeV. The result shows that in the energy range of 0.5 to 100 GeV, the efficiency of the photon identification can reach 90% with purity of 90%.