The lead-glass electromagnetic calorimeter for the SELEX experiment

A large-acceptance, highly segmented electromagnetic lead-glass calorimeter for Experiment E781 (SELEX) at Fermi National Acceleration Laboratory was designed and built. This detector has been used to reconstruct photons and electrons with energies ranging from a few GeV up to 500 GeV in the collisions of the 600 GeV Σ- hyperons, π mesons and protons with the target nucleons. The design, calibration and performance of the calorimeter are described. Energy resolution and position resolution are assessed using both calibration electron beams and π0 mesons reconstructed in 600 GeV hadron-hadron interactions. The performance of the calorimeter in selecting resonant states that involve photons is demonstrated.