The shower shape of n, n^-, p, p^-, K^＋, π^＋ and photons, generated by JPCIAE code for 5.5 TeV/A ^208pb＋^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%.
本工作用JPCIAE事件产生器模拟5.5 TeV/A 208Pb+208Pb对撞产生的7种粒子n、n-、p、p-、K+、π+和光子入射的环境下,对ALICE(A Large Ion Collider Experiment)光子谱仪(PHOS)的光子判别的效率和纯度进行了模拟研究。在簇射形状分析中,采用主成分分析方法将7 参数分析问题约简为2 参数,给出不同能区中的光子判别效率与纯度的关系。
