Efficiency and spatial resolution measurements of a modular neutron detector in the kinetic energy range 15–120 MeV

Abstract The detection efficiency of a 3 × 3 matrix of NE 110 scintillator blocks, 153 × 153 × 270 mm long, has been measured in the neutron kinetic energy range 15–120 MeV for several thresholds, ranging from 2.80 to 15.75 MeV equivalent electron energy, and for various thicknesses of lead shielding in front of the counter. The probabilities of detecting a neutron in a block different from the one struck by the beam (‘mixing’) and in more than one block (‘multifiring’) have also been measured as a function of threshold and shielding. Comparisons have been made with a Monte Carlo program which accounts for the modular structure of the counter. The efficiency and the spatial resolution of a very large matrix have been obtained, using both experimental and Monte Carlo results.