CHARACTERISTICS AND PERFORMANCE OF AN ELECTROMAGNETIC SHOWER SAMPLINGCALORIMETER WITH WAVELENGTH SHIFTING FIBER READOUT

We have studied the properties of electromagnetic shower counters made of scintillator and lead tiles of different thickness. Light collecti on is achieved by wavelength shifting fibres sparse in the body of the calorimeter. The counters were tested in a beam of electrons, pions a nd muons with energies between 2 and 8 GeV. We report here the final r esults of the test. The energy resolution is in good agreement with wh at is expected from the sampling fraction, i.e. sigma/E = 0.07/root E, the non uniformity of the response is less than 1% at the centre of a counter and 7 in the boundaries between modules, and the pi/e contami nation is at the level of a few 10(-3). Performance of the calorimeter with readout systems able to operate in magnetic field is also report ed.