Abstract:
The present study emphasizes to analyze the ionizing radiation shielding effectivenessof mono-energetic photon of X-rays (65 keV to164 keV) and relatively high energy ɣ-rays (137Cs; 661.5 keV to60Co; 1250 keV) for the determination of shielding design of radiation facilities. Composites were fabricated by indigenous low-cost materials such as raw beach sand (RBS) of Cox’s Bazar, Magnetite-Ilmenite (MI), Inland Sand (IS), Dyeing Sludge (DS) as filler and Madupur clay as binder and base matrix. The X-ray and γ-ray attenuation efficacies of the prepared composites and ordinary concrete (OC) were characterized and assessed using broad beam transmission geometry, GM detector, and stated in terms of linear attenuation coefficients (LAC), mass attenuation coefficients (MAC), Half Value Layers (HVL) and Effective Dose Rates (EDR). The key elements of these prospective samples were measured to analyze the presence of heavy elementsby Neutron Activation Analysis (NAA) method using the TRIGA Mark-II Research Reactor.The attenuation efficiencies were also explained with the help of the entire internal structural morphology of the composites by thermal neutron radiography technique. The LAC values of MI composite and RBS composite decrease from 1.6443cm-1 to 0.1459cm-1 and 1.4026cm-1 to 0.1377cm-1for 65 keV to 1250 keV respectively, which reveals the higher level of attenuation among the studied composites. The LAC data of ordinary concrete has exhibited a moderate level of attenuation (0.7189 cm-1to 0.1314 cm-1 for 65 keV to 1250 keV). The ISand DS composite showed the poor attenuation capacity, the LAC falls down from 0.5150 cm-1 to 0.0974 cm-1and 0.5133 cm-10.0949 cm-1for 65 keV to 1250 keV, respectively. The MAC & EDR data with the increasing photon energy follows a similar pattern as LAC data.The sequences of HVL of the composites are MI<RBS<OC<IS. The morphology study reveals that the finely structured clay-based MI and RBS composites have lower gray values at various pixel points. The current experimental observations would be useful for designing potential radiation shielding materials atradiation facilities based on the indigenous cost-effective raw materials.
Key-words: Linear attenuation coefficient (LAC), mass attenuation coefficient (MAC), half value layer (HVL), photon energy, raw beach sand, minerals, Madhupur clay etc.
