Determination of neutron cross sections of iron and water between 0.3 and 11 MeV

Total neutron cross-sections of iron and water have been determined experimentally using a continuous neutron spectrum emitted from one of the horizontal channels of the ET-RR-1 reactor. Measurements have been carried out using neutron spectrometer with single stilbene scintillator. The gamma background was rejected from the measured pulses by a compensation method based on the differences in the shape of neutrons and gamma pulses. The measured pulse amplitude distributions were transformed to neutron energy distributions by means of a differential method. The measured fast neutron spectrum leaking directly from the reactor core and that transmitted through iron and water barriers were used to evaluate the total cross-sections for neutrons of energies between 0.3 and 11 MeV for these materials. Comparison between the values of obtained cross-sections and that given by others shows that a reasonable agreement could be observed between the two for neutrons of energies >1.5 MeV. However, for neutrons of energies <1.5 MeV a large discrepancy was observed. This could be attributed to the failure of the discriminating technique used in these measurements to separate between neutron and gamma pulses. (author)