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[en] The method applied represents poisoning with ''non-reciprocal v absorbers'' and is to define the thermalizing parameter M₂ of neutrons in a water lattice with hollow channels, 2 cm stepped and a porosity of 0,2442. The pulse experiments were carried out on a IRT - 2000 reactor in Sofia with the help of a very fast mechanical selector. The M₂ values recieved for water (5,097 cm^-1) were compared to the theoretical values, calculated by Honeck. The value for M₂, registered for the examined lattice (2,92 cm^-1), confirming to a rule, is lower than the experimental value for water, which is in connection with the relative reduction in the concentration of the dispersive water nucleuses and also, quite probably, with the changes in the neutron spectrum, caused by the diffusion cooling in the lattice

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[en] The dependence of the neutron pulse attenuation constant on the concentration of hydrogen nuclei was investigated for two-zone homogeneous hydrogen-containing materials: plexiglas, water, hexane and benzene. The sensitivity of the neutron pulse method was determined by varying the hydrogen content in the studied medium with reference to a standard one. The results showed that, in order to achieve a satisfactory accuracy, the variations in relative hydrogen content should be not less than 15%. Therefore, the method is suitable only for rough estimation of the hydrogen content in two-zone systems

No abstract available