Measurements of Backscattered Neutrons and Secondary Gamma-Rays from Stainless Steel and Limestone Concrete for 14-MeV Source Neutrons

Abstract

Simultaneous measurements of fast neutron and prompt r-ray albedos were performed by nominal 14-MeV neutrons for the type 304 SS and the limestone concrete. Both neutrons and r-rays were detected by an NE-213 scintillator with the aid of the n-r discrimination circuit.The time-of-flight method was used to obtain neutron spectra, whereas the unfolding method was applied to analyze r-ray pulse-height data of the scintillator. The measured data were compared with those calculated by the MCNP code with the ENDF/8-IV data.The calculation reproduced the measured secondary r-ray differential albedo data well for both materials. For neutrons, apparent disagreement was seen in the albedo data of the 304 SS between the calculation and the experiment. This was due to some inaccuracies in the chromium cross sections in the ENDF /8-IV. The agreement of the neutron data was better for the limestone concrete than for the 304 SS.