High efficiency method of fast neutron detection by oxide scintillators for detection systems of fissionable radioactive substances

Comparative measurements and analysis of detection efficiency (DE) of fast neutrons from
²³⁹
Pu-Be source have been carried out in a broad energy range En ~ 0.1 ÷ 10 MeV using oxide scintillators BGO, GSO, CWO, ZnWO, ZnSe(Te, O), as well as LiI(Eu). DE of fast neutrons by heavy oxide scintillators was found to be very high (~ 40-50 %). The neutron inelastic scattering reaction (n, n'y) is considered as the most probable interaction mechanism of neutrons with nuclei of heavy oxide scintillators. It is concluded that heavy oxide scintillators, which are at the same time efficient gamma-detectors, allow creation of a highly efficient gamma-neutron detector ensuring high detection efficiency of fissionable radioactive substances.