Energy measurement of ²⁴¹Am-⁹Be neutrons by tagged neutron time-of-flight

Neutron energy spectrum of a ²⁴¹Am-⁹Be source was measured in the energy range of 0.3 to ∼ 6.5 MeV using γ-ray tagged neutron time-of-flight method. BC501A type organic liquid scintillator detector was used at a flight path of 175 cm to detect neutrons with good energy resolution. The de-excitation γ-ray emitted in coincidence with neutrons was detected using a fast BaF₂ detector. The measured data has been compared with the ISO 8529-2 standard neutron reference spectrum and found good agreement in the overlapping energy region. Present measurement applied efficiency correction to the data and extended up to 0.3 MeV in the lower energy region compared to earlier reported measurement using similar technique.