Study on Clay Bentonite and Kaoline as Shielding Material

Lead (Pb) is a main shielding material for gamma radiation. Lead has a high number of atoms and density. However, lead is toxic, very heavy and has low neutron absorption capacity. Therefore, a shielding material with ideal characteristics such as lightweight and high radiation attenuation are actively being explored. Among the shielding material that currently being studied are those made of clay. Clay has high melting point, thermochemical stability and high mechanical strength. These features make the clay potentially be used as a shielding material. Therefore, this study was carried out to determine the element presence in the clay, the attenuation coefficient and the comparison of lead-equivalent thickness values for clay (i.e. bentonite and kaoline). The details of the clay elements were determined by using X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM). Clay combustion tests were conducted at similar to 1000 degrees C in order to see any changes in the physical and chemical properties. Meanwhile, the test for the determination of the attenuation coefficient was performed using a source of gamma and X-ray. The results showed that no significant changes in the chemical and physical properties of the clay after the combustion test. Based on the attenuation coefficient, bentonite has a higher attenuation coefficient compared to kaoline with almost 90% of dose reduction achieved. Finally, lead equilibrium thickness analysis showed that bentonite equilibrium value was higher than kaoline. In conclusion, bentonite shows high reduction of dose capability to be used as a radiation shielding.