Measurement of fast neutron spectra from iron shielded americium-beryllium source

The measurements were carried out using the zero-crossing technique of pulse-shape discrimination system to distinguish neutron from gamma-ray pulses. The neutron spectra have been evaluated from measured pulse-height distribution using computer code based on an unfolding method. Results obtained in measurements are compared to the results of fast neutron shielding calculations estimated by PMK computer code. The subgroup approximation and Monte Carlo method were applied in calculations. A brief survey of results and a discussion are presented. 7 refs., 3 figs., 1 tab. (Author)