A comparison of methods for determining neutron detector efficiencies at medium energies

We compare the 'Lithium Activation' (LiA) method and the 'Isospin Clebsch-Gordan Ratio' (ICGR) method for determining detection efficiencies of neutrons between 100 and 160 MeV. Each method was used to determine the efficiency by relating a measured neutron yield to a cross section measured in another way: γ-ray activation cross sections for LiA; (p, p') cross sections from experiments at the Indiana University Cyclotron Facility for ICGR. Efficiencies determined by the two methods disagree substantially. Efficiencies calculated with the Monte Carlo code of Cecil et al. agree with the ICGR results. We conclude that the Lithium Activation method is inconsistent at these energies. (orig.)