Photon reconstruction and identification at sqrt(s) = 7 TeV

We describe the commissioning of photon reconstruction and identification in the CMS experiment using 74 nb$^{-1}$ of integrated luminosity collected at the LHC at $\sqrt{s}$ = 7 TeV. The most important observables for photon reconstruction, identification, and isolation have been measured and compared with the Monte Carlo simulation. Results are first shown for a loosely selected, background-dominated sample. A robust photon selection to be used for commissioning and early analysis is then described. Results for a signal-enriched sample using this selection are then presented. The commissioning of new observables designed for the identification of the conversion of isolated photons is then discussed. Finally, the contamination of the sample from beam halo bremsstrahlung is investigated, and an upper limit on such contamination for the current sample is established.