Spectroscopic and thermal analysis of lead-free multipurpose radiation shielding glasses

Abstract

The genetic algorithm was used to identify glasses, of the composition 50Bi2O3-(50-x) B2O3-xBaO with 25≥x≥5 wt%, that have a similar half-value layer (HVL) and neutron removal cross-section. The structure of these glasses was further explored using a combination of spectroscopic and thermal analysis in order to ascertain whether they possess advantageous physical properties comparable to traditional materials used in nuclear reactor design. Differential scanning calorimetry (DSC) analysis was used to examine the thermal profile of the glass system and to identify glass transition temperature Tg and softening temperature Ts. Glass of the composition 50Bi2O3–30B2O3–20BaO had exhibited the highest thermal stability. Analysis of the Raman spectra of the samples confirmed the presence of BiO6 octahedrons and B-O-B bonds in poly borate chains. A deconvolution of the IR spectra was carried out to determine the relative proportions of BO3 triangles to BO4 tetrahedral units in the glass network that would affect the density and bulk modulus. Optical absorption spectrum of the samples exhibited absorption peaks in the blue region along with a broad band of absorption at longer red wavelengths associated with excitation of bismuth ions. When compared to traditional heavy concretes used in radiation shielding, the bismuth-barium borate glasses exhibited superior performance over conventional barite concrete as a gamma-radiation shield and was comparable to limonite concrete as a neutron radiation shield. The bulk modulus of the glass series was also found to be comparable to that of regular concrete at approximately to 30 GPa.