The L3 Bgo Electromagnetic Calorimeter

The L3 detector at LEP will contain a unique electromagnetic calorimeter, consisting of 11488 scintillating bismuth germanate crystals, with silicon photodiode readout. The expected resolution is less than 1% for energies from 5 GeV to 50 GeV, rising to 5% at 100 MeV. The first part of the final detector (3840 crystals) is being assembled at CERN, and is to be calibrated in a test beam in the summer of 1987. The design of the calorimeter and its large dynamic range electronics are discussed.