Thermal-to-fast neutron cross section of concrete for radiation protection applications

Heavy concrete for radiation shielding is obtained by adding heavy natural aggregates such as barite or magnetite in the mixing process. While the addition of barite provides an increased capture cross section for fast neutrons, preliminary results showed that the effect for epithermal and thermal neutrons is to significantly decrease the total cross sections, as a consequence of the reduced amount of structural hydrogen. We propose a neutron transmission measurement on VESUVIO the range 1 meV to 1 MeV for a larger set of baritic concrete samples, combined with a SEM-EDS characterization under different vacuum conditions. The recent VESUVIO upgrade allows a broader range for the measurement of the neutron cross section, and this will help in the definition of the optimal amount of barite in concrete for radiological protection in hospitals and nuclear power plants.