Some Applications of the Gold Activation by Environmental Neutrons

The activation of gold by environmental neutrons was used to study the effect of concrete buildings at our laboratory (LLRL) on the neutron flux, and to estimate the thermal neutron flux in and around the building of Kinki University Training Reactor (UTR-Kinki). The results showed that three ceilings of thickness (34 g/cm2 each) decrease the fast neutrons to 26 %. However, the same reinforced concrete decreases the slow flux to only 62 %. On the other hand, the thermal neutron flux at 283m from the reactor center was two times higher than the environmental background. These results can give attention to the effect of concrete walls as a shielding around the reactors, especially those that have been hold near to the living environments.