Comparison of Electromagnetic Shower Profile in 1996 Test Beam and GEANT Simulation

The lateral dimensions of the electromagnetic shower in the lead tunsgtate ( PbWO4) crystals have been studied in 1996 test beam data and the results compared to the GEANT simulation. A set of events scanning across the crystal has been chosen and the shower containment in the central crystal has been studied as a function of the impact point on the crystal. It is shown that the simulation and the data agree fairly well, but the GEANT simulation has a tendency to overestimate he shower dimensions. A very good agreement is obtained if the lateral width of the GEANT shower is reduced by 6%.