Characterization and Radiation Shielding Properties of Philippine Natural Bentonite and Zeolite

Abstract

In this paper, the investigation of the structural and radiation shielding characteristics of natural bentonite and zeolite was presented. XRD (X-ray diffraction) and SEM (scanning electron microscopy) were used to examine the structural properties and morphologies of the minerals. The Electron-Photon Interaction Cross Sections 2017 (EPICS2017) library through EpiXS software was used to obtain the photon shielding properties – including mass attenuation coefficients, mean free paths, half-value and tenth-value layers, effective atomic numbers, and buildup factors for energy absorption and exposure. The ESTAR web program and SRIM code were used to obtain electron and ion stopping powers and ranges. The neutron removal cross-sections and the fast and thermal attenuation factors were obtained using the Phy-X/PSD, MRCsC, and NGCal software. The results showed that the zeolite grain sizes were typically smaller than 50 µm, while the bentonite grain sizes were larger reaching 100 µm. It was found that both materials were significantly composed of mordenite and montmorillonite. The photon shielding quantities for both materials showed similar MFP, HVL, and TVL values with different buildup factor values at large penetration depths. The high-energy charged particle range within both materials described similar trends and values. The range of alpha particles was significantly smaller than the average grain sizes for both materials. The fast neutron removal cross-sections of zeolite and bentonite were significantly higher than for typical soil values. Both natural materials may be suitable candidate ingredients for radiation shielding composites, especially due to their natural abundance and unique properties.