Photon discrimination simulation with the PCA method

The shower shape of n,(n),p,(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%.