SPECTRAL DISTRIBUTION OF SECONDARY GAMMA-RAYS IN FIBER CONCRETE SHIELDS

When concrete is used for neutron and gamma shielding, its shielding e ffectiveness for gamma radiation can be improved by addition of iron. However, secondary gamma radiation will be produced as a result of ine lastic scattering of fast neutrons and capture of thermal neutrons by iron nuclei. The spectral distribution of the secondary gamma radiatio n in ilmenite-limonite concrete with addition of steel fibres was inve stigated. It is shown that the linear attenuation coefficient for seco ndary gamma radiation has its maximum at a steel fibre concentration o f 2 per cent.