THORIUM AND URANIUM CONTENT DETERMINATION USING DOUBLE GAMMA-IRRADIATION

A new technique for the determination of Th and U content in solids wa s proposed. The ratio of U and Th fission reaction yields for ''infini te thick'' metall layers was measured in the gamma-ray energy range fr om 7 MeV to 23.5 MeV. For this purpose metallic sheets of U and Th pla ced next to polyethyleneterephtalate track detectors were irradiated a t the Microtron MT-25. The method is based on the fact that the ratio N-U/INTh differs sufficiently from 1.7 to 3.3 depending on the gamma-r ay energy. Irradiating an Uranium ethalon and samples with gamma-rays of (20-23) MeV (N-U/N-Th = 2.2) and (15-17) MeV (N-U/N-Th = 3.3) one c an determine simultaneously both U and Th content in samples. The comp arison of the results of measuring of U and Th content in different sa mples obtained by the proposed and the known methods is presented.