Decision-Taking Procedure for Explosives Detection by Nuclear Technique

Abstract

One of the most promising techniques of explosives detection is based on detection of secondary γ-rays that are induced in the inspected object or area by a flux of neutrons (the so-called “neutron-in gamma-out” method). Fast neutrons undergo mostly inelastic scattering (n,n’γ) while thermal neutrons undergo mostly radiation capture (n,γ) reactions on nuclei inside the object. Spectra of secondary γ-rays contain information about the isotopic composition of the object. By using narrow (few nanoseconds) time gates one can determine the time of arrival of the given γ-quantum with respect to a particle which accompanies neutron emission from the neutron source, and thus split the total γ-spectrum into fast (inelastic scattering) and slow (radiation capture) components.