RESUMEN
In this study, a series of "Epoxy-Clay-PbO" nanocomposites under the name of ECPNCs were prepared by the molding method, and their physico-mechanical properties were investigated by different techniques. Focus of the work, was on the shielding ability of the ECPNCs for the gamma rays, emitted from Ir-192, Cs-137 and Co-60 with a wide range of energy. Scanning electron microscopy, and X-ray diffractometry demonstrated that clay platelets were fully exfoliated, and the PbO particles were homogenously distributed in the polymeric matrix. Thermo-gravimetric analysis and standard tensile tests revealed that PbO content has an "increasing/decreasing" effect on "thermal stability/mechanical strength" of the nanocomposites. Gamma shielding experiments showed that efficacy of ECPNCs containing 30â¯wt% PbO was 47% better than that of concrete. Experimental attenuation data were confirmed by theoretical calculations, so that the maximum difference between them was 14.1%. Furthermore, a correlation was developed between PbO content of the ECPNCs and their mass attenuation coefficient for all gamma sources.
RESUMEN
For designing an appropriate neutron beam, the determination of neutron flux at any irradiation facility is an important key factor. Due to the importance of determining the thermal and epithermal neutron fluxes in a typical thermal column of a reactor, a simple and accurate technique is introduced in this study. Absolute thermal and epithermal fluxes were measured experimentally at a certain point using the foil activation method by neutron bombardment of bare and cadmium covered Au foils. The relative neutron fluxes were also derived simply by means of Monte Carlo simulation by accurate modelling of the reactor components. Finally, by normalization of the relative distribution flux with regard to information about the absolute neutron flux, the accurate thermal and epithermal neutron distributions were derived, separately.