Determination of intrinsic fluctuations and energy response of Si/Fe and Si/Fe + Pb calorimeters up to 70 GeV of incoming hadron energy

Fluctuations due to binding energy losses were determined experimentally for sampling hadron calorimeters with layers of silicon mosaics as active medium and with either Fe layers (Si/Fe) or combinations of Pb and Fe layers (Si/Fe + Pb) as absorbers. The calorimeters were exposed to hadrons (π) at incoming energies of 10, 15, 20, 30, 40, 50 and 70 GeV at the CERN-SPS. The contributions (σbind) of the binding energy losses fluctuations to the energy resolution of these hadron calorimeters were found to be σbind = (19.8±2.4)% and (49.9±14.1)% for Fe and Pb, respectively. σbind = (25.9±2.1)% has been found for a compensating Si/Fe + Pb calorimeter. These results are found in good agreement with previous measurements made at lower energies. As expected, an overall nonlinearity of about 3.5%, in the 10–70 GeV energy range, has been observed in the Si/Fe noncompensating (e/π∼ 1.11 at 10 GeV) calorimeter energy response.