The lead-glass electromagnetic calorimeter for the SELEX experiment

Abstract 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 π 0 mesons reconstructed in 600 GeV hadron–hadron interactions. The performance of the calorimeter in selecting resonant states that involve photons is demonstrated.