METHOD FOR THE DETECTION AND NON-DESTRUCTIVE ASSAY OF SUBSTANCES CONTAINING NUCLEI OF LIGHT ELEMENTS

摘要

The present invention relates to a method for the detection and non-destructive assay of substances containing nuclei of light elements with an atomic mass not exceeding 30, including organic substances. This method may be used to avoid any accidental or intentional screening or covering of the substance studied in the object undergoing analysis, whether it be due to the baggage or to other objects that prevent the integrity of substances from being penetrated or broken for studying their content. The object to be analysed is irradiated using a flow of rapid mono-energetic neutrons generated by the reaction in the target material. The elementary composition and the three-dimensional distribution of the substances in the object to be analysed are estimated from the mass values of the nucleus of elements penetrating therein. These masses are in turn determined according to the energy and dispersion angle values of the neutrons and using the known moments of dispersion as well as the energy value and the initial movement vectors, said neutrons being submitted to a single elastic dispersion in the substances of the object analysed. The method also uses from the co-ordinates of the points where such dispersion occurs.