Performance of the CHORUS lead-scintillating fiber calorimeter

We report on the design and performance of the lead-scintillating fiber calorimeter of the CHORUS experiment, which searches for νμ-ντ oscillations in the CERN Wide Band Neutrino beam. Two of the three sectors in which the calorimeter is divided are made of lead and plastic scintillating fibers, and they represent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is built using the sandwich technique with lead plates and scintillator strips and acts as a tail catcher for the hadronic energy flow. From tests performed at the CERN SPS and PS an energy resolution of σ ( E ) / E = ( 32.3 ± 2.4 ) % / E ( GeV ) + ( 1.4 ± 0.7 ) % was measured for pions, and σ ( E ) / E = ( 13.8 ± 0.9 ) % / E ( GeV ) + ( − 0.2 ± 0.4 ) % for electrons.