RESPONSE TO ELECTRONS AND PIONS OF THE CALORIMETER FOR THE CHORUS EXPERIMENT

We built and tested on charged particle beams the high energy-resoluti on calorimeter for the CHORUS experiment, which searches for nu(mu)-nu (tau) oscillations in the CERN Wide Band Neutrino Beam. This calorimet er is longitudinally divided into three sectors: one electromagnetic a nd two hadronic. The first two upstream sectors are made of lead and p lastic scintillating fibers in the volume ratio of 4/1, and they repre sent the first large scale application of this technique for combined electromagnetic and hadronic calorimetry. The third sector is made of a sandwich of lead plates and scintillator strips and complements the measurement of the hadronic energy flow. In this paper, we briefly des cribe the calorimeter design and we show results on its response to el ectrons and pions, obtained from tests performed at the CERN SPS and P S. An energy resolution of sigma(E)/E=(32.3+/-2.4)%/root E(GeV)+(1.4+/ -0.7)% was achieved for pions, and sigma(E)/E=(13.8+/-0.9)%/root V(GeV )+(-0.2+/-0.4)% for electrons.