Performance studies of lead/scintillating-fibre calorimeters in the 1 to 10 GeV range

Three calorimeter modules made of scintillating fibres embedded in a lead matrix were tested at the CERN Proton Synchrotron. The linearity of the energy response to electron-induced showers, measured in a module having a lead-to-fibre volume ratio of 1.8, is verified within 2.5% whilst the energy resolution is found to be 9.6% E + 1% at 6° and 4° impact angles in the horizontal and vertical planes. An impact position resolution of 1.51 mm E + 1.45 mm is achieved. The e/π^± separation based on the longitudinal and transverse shower size is discussed for various calorimeter configurations. Requiring an energy above a threshold of 3 GeV leads to a π^± rejection factor of 12 to 36 with longitudinal criterium, and a π^± rejection factor of 43 to 100 with a transverse cut in a π^± energy range of 3 to 7 GeV. A combination of both criteria leads to a rejection factor between 116 and 303 in the same energy range. The study of the time shape of the signals shows a very small intrinsic jitter of 0.4 ns on the calorimeter signals. It does not show any evidence of a detectable neutronic tail in π^± signals.