Energy resolution calculation of the PWO calorimeter, comparison with the beam tests

The basic parameters of a PbWO4 crystal calorimeter are GEANT evaluated to optimize its energy resolution in the photon energy range from tens of MeV to hundreds of GeV. The energy resolution is well factorized in this region as a function of scintillation efficiency, thanks to a high transparency of the crystal. The calculated energy dependence of the resolution fits the results of the first beam measurements.