Measuring the shielding properties of concrete samples

The shielding properties of various concrete mixtures against gamma fields and thermal neutron fields were measured by using the attenuation of the neutron flux after passage through concrete blocks. The characteristic parameters included linear coefficients of attenuation of gamma radiation (for the gamma energy of 661 keV and for the group of energies of 661, 1173 and 1332 keV) and, for the measurements with thermal neutrons, half-thickness of the concrete material. The Fe and Ba contents affected most the shielding properties against gamma rays, whereas the B, Be and Li, and also K, were most relevant against thermal neutrons. (P.A.)