Structural properties of Bi2O3–B2O3–SiO2–Na2O glasses for gamma ray shielding applications

Impact of bismuth oxide on structural, optical and gamma-ray shielding properties of calcium-sodium-borate glasses

In the present study, we have prepared six glass samples of bismuth borate using the melt-quenching method with the composition (70-x)B2O3-10CaO-20Na2O-xBi2O3; x = 0, 3, 6, 9, 12 and 15 mol%. The density of the prepared glasses was determined using Archimedes principle. The X-ray diffraction patterns provide confirmation of the amorphous nature of the prepared samples, whereas the Fourier transform infrared measurements pointed to the existence of structural units like BO3, BO4, BiO3 and BiO6 within the glass network. An assessment of the optical absorption spectra unveiled that with the increase in the bismuth oxide content, there was a decrease observed in both the direct and indirect band gap energies. Specifically, they decreased from 3.40 to 2.79 eV and from 3.10 to 2.46 eV, respectively. The properties related to gamma ray attenuation, including the mass attenuation coefficient (μm), effective atomic number (Zeff), half-value layer (HVL) and mean free path (MFP), were examined for all the glass samples. This investigation was carried out using the Phy-X/PSD software, covering the energy range from 0.511 to 1.332 MeV. Out of all the samples, Bi-15, featuring the highest Bi2O3 content, demonstrated the highest μm, Zeff, the smallest HVL and MFP. These results suggest that the glass with 15 mol% of Bi2O3 offers the most effective gamma radiation shielding performance. Moreover, the glasses examined in this study exhibit superior radiation shielding characteristics compared with specific concrete types, namely, ordinary concrete, Hematite serpentine concrete and barite concrete, as well as commercial glasses such as RS-360 and RS-253.

An Alternative Radiation Shielding Material Based on Barium-Sulphate (BaSO4)-Modified Fly Ash Geopolymers

Geopolymers are a new environmentally friendly cementitious material, and the application of geopolymers can reduce the carbon dioxide emissions caused by the development of the cement industry. Purpose: This study investigates the radiation shielding capacity of fly ash geopolymers (FAGP) as a viable alternative to conventionally used ordinary Portland cement (OPC) due to the high demand for an environmentally friendly, cost-effective and non-toxic shield material. Methods: The FAGP material was fabricated and combined with Barium sulphate (BaSO₄) at different ratios (0, 5, 10 and 15%). Different thicknesses (3, 6 and 9 cm) of the samples were also prepared. An energy-dispersive X-ray (EDX) was used to determine the elemental percentages of the materials, which were then used to calculate their effective atomic number (Z_eff). An ion chamber was used to detect the dose of radiation transmitted through the samples. Results: The lowest radiation dosage (34.68 µGy) and highest Z_eff were achieved with FAGP combined with 15% BaSO₄ at 9 cm thickness. The decrease in radiation dosage can be attributed to the increase in Z_eff with the addition of BaSO₄ to FAGP, which in turn increases the density of FAGP. Conclusions: Thus, the radiation dose can be significantly reduced with a higher ratio of BaSO₄ to FAGP. This study shows that FAGP combined with BaSO₄ is a promising radiation shielding material, as well as a viable alternative to OPC.

Lead-free transparent shields for diagnostic X-rays: Monte Carlo simulation and measurements

In recent years, the preference for using lead-free radiation protection shields has increased because of concerns regarding lead poisoning and leakage. In medical and research laboratories, glass shields are preferred because of their transparency. In this study, various glass shields were examined and compared based on the international standards. One commercially available lead-based shield, four recently studied shields, and three new lead-free shields were considered, and their shielding factors were calculated. We presented three glasses based on borate, phosphate, and silicate compounds, which were named Ir₁, Ir₂, and Ir₃, respectively. Based on the International Electrotechnical Commission standard (IEC 61331), the air-kerma ratios (attenuation ratios) and lead equivalent values were derived using Monte Carlo N-Particle eXtended (MCNPX) calculations, and mass attenuation coefficients and effective atomic numbers (Z_eff) of all the shields were obtained from XCOM database, in the diagnostic X-ray energy range of 40-120 keV. In addition, some measurements were performed for the reference (lead-based) glass to validate the simulations. The above-mentioned factors for silicate-bismuth-based (Ir₃) and borosilicate-barium-based (Tu) glasses were found to be higher than the others and comparable to those of commercially available lead-based glass. In conclusion, Ir₃ and Tu glasses were found to be the preferred lead-free transparent shields in the diagnostic X-ray energy range.

Investigation of bismuth borate glass system modified with barium for structural and gamma-ray shielding properties

In the present paper, transparent and non-toxic Bi₂O₃-B₂O₃ glasses doped with BaO have been prepared by the authors which may replace the standard radiation shielding concretes and lead based commercial glasses for gamma ray shielding applications. The effects of BaO on the structural and optical properties of the prepared glass system have been investigated by Raman, FTIR and UV-Visible techniques. It has been observed that barium plays the role of a modifier and it is responsible for conversion of triangular [BO₃] units to tetrahedral [BO₄] units along with formation of non-bridging oxygen and increase in ionic character. It also improves the radiation shielding abilities of the glass system. The mass attenuation coefficients for gamma-ray photons at 662 keV energy by using ¹³⁷Cs radioactive source have been measured by employing narrow beam transmission geometry. This was accompanied by theoretical computation of mass attenuation coefficients in the wide photon energy range varying from 1 keV to 100 GeV. It has been found that values of mean free path and tenth value layer decrease whereas, density and effective atomic number increase with the increase of barium oxide content. As compared with barite concrete and commercial shielding glass RS-360, our prepared Bi₂O₃ - BaO - B₂O₃ glasses have shown better gamma ray shielding properties. This implies that the prepared glass system is a better gamma ray absorber and it has the potential for use in gamma-ray shielding applications.

A novel method of utilization of hot dip galvanizing slag using the heat waste from itself for protection from radiation

A novel, unconventional, low cost, eco-friendly and effective shielding materials have been made utilizing the hot dip galvanizing slag using the heat waste from itself, thereby saving the natural resources and preventing the environmental pollution. SEM-EDS of shielding materials indicates that the other elements are distributed in Zn element. The mass attenuation properties of shielding materials were measured using a narrow beam geometrical setup at 0.662MeV, 1.17MeV and 1.33MeV. The half value thickness layer, effective atomic number, and electron density were used to analyze the shielding performance of the materials. The EBFs and EABFs for the prepared shielding materials were also studied with incident photon energy for penetration depths upto 40mfp. The shielding effectiveness has been compared with lead, iron, zinc, some standard shielding concretes, different glasses and some alloys. The shielding effectiveness of the prepared samples is almost found comparable to iron, zinc, selected alloys and glasses while better than some standard shielding concretes. In addition, it is also found that the bending strength of all shielding materials is more than 110MPa.

Toward a Slow-Release Borate Inhibitor To Control Mild Steel Corrosion in Simulated Recirculating Water

On the basis of their potential passivating characteristics, in this study, borates have been used to synthesize a novel slow-release inhibitor to suppress long-term mild steel corrosion in simulated recirculating water. The passivating performance was characterized by various electrochemical measurements and the passivating mechanism was interpreted by the point defect model. The experimental results indicated that the slow-release inhibitor exhibited a passivating efficiency of over 98% after 30 days of immersion, due to the formation of a passive film that was predominant by a Fe-O-B structure on the mild steel surface. This study provides a novel controlled-release concept and a slow-release borate inhibitor to control long-term corrosion.