Experimental Investigation of Radiation Shielding Competence of Bi2O3-CaO-K2O-Na2O-P2O5 Glass Systems

The gamma-ray shielding features of Bi₂O₃-CaO-K₂O-Na₂O-P₂O₅ glass systems were experimentally reported. The mass attenuation coefficient (MAC) for the fabricated glasses was experimentally measured at seven energy values (between 0.0595 and 1.33 MeV). The compatibility between the practical and theoretical results shows the accuracy of the results obtained in the laboratory for determining the MAC of the prepared samples. The mass and linear attenuation coefficients (MACs) increase with the addition of Bi₂O₃ and A4 glass possesses the highest MAC and LAC. A downward trend in the linear attenuation coefficient (LAC) with increasing the energy from 0.0595 to 1.33 MeV is found. The highest LAC is found at 1.33 MeV (in the range of 0.092–0.143 cm⁻¹). The effective atomic number (Z_eff) follows the order B1 > A1 > A2 > A3 > A4. This order emphasizes that increasing the content of Bi₂O₃ has a positive effect on the photon shielding proficiencies owing to the higher density of Bi₂O₃ compared with Na₂O. The half value layer (HVL) is also determined and the HVL for the tested glasses is computed between 0.106 and 0.958 cm at 0.0595 MeV. The glass with 10 mol% of Bi₂O₃ has lower HVL than the glasses with 0, 2.5, 5, and 7.5 mol% of Bi₂O₃. So, the A4 glass needs a smaller thickness than the other glasses to shield the same radiation. As a result of the reported shielding parameters, inserting B₂O₃ provides lower values of these three parameters, which in turn leads to the development of superior photons shields.     

Nonlinear Optical Limiting and Radiation Shielding Characteristics of Sm2O3 Doped Cadmium Sodium Lithium Borate Glasses

Strong nonlinear absorption (NLA), reduced optical limiting (OL) thresholds, and high radiation shielding parameters are required for the effective use of glasses in the laser radiation and nuclear radiation protecting materials. In view of this, the efficacy of Sm₂O₃ on the nonlinear optical (NLO) and OL properties were ascertained (at 532 nm) along with radiation shielding characteristics. The open and closed aperture Z-scan profiles revealed the presence of positive NLA and nonlinear refraction (NLR) phenomena respectively. OL measurements showed the existence of limiting behavior in the studied glasses. The NLA and NLR coefficients were improved while the OL thresholds were decreased as the doping of Sm₂O₃ elevated to a higher doping level. These improvements in NLA, NLR coefficients and OL efficiencies were attributed to the non-bridging oxygens and high polarizable Sm³⁺ ions. The NLA and OL results clearly suggest the high (5 mol %) Sm₂O₃ doped glass (Sm5CNLB) glass is beneficial to protect the delicate devices and human eye by suppressing the high energy laser light. The theoretical linear attenuation coefficients (LAC) values of the presented SmxCNLB glasses were obtained with the help of Phy-X software between 0.284 and 1.333 MeV. At 0.284 MeV, the maximum values occur and take values between 0.302 (for Sm0CNLB) and 0.409 cm⁻¹ (for Sm5CNLB). We found that the LAC for the presented SmxCNLB glasses is a function of Sm₂O₃ content, where the LAC tends to increase, corresponding to the high probabilities of interaction, as the content of Sm₂O₃ changes from 0 to 5 mol %. The effective atomic number (Z_eff) for the presented SmxCNLB glasses was examined between 0.284 and 1.333 MeV. As the amount of Sm₂O₃ is added, the Z_eff increases, and this was observed at any energy.     

Fabrication of Lead Free Borate Glasses Modified by Bismuth Oxide for Gamma Ray Protection Applications

In the present work, bismuth borate glass samples with the composition of (99-x) B₂O₃ + 1Cr₂O₃ + (x) Bi₂O₃ (x = 0, 5, 10, 15, 20, and 25 wt %) were prepared using the melt quenching technique. The mass attenuation coefficient (MAC) of the prepared glass samples was measured through a narrow beam technique using a NaI(Tl) scintillation detector. Four point sources were used (²⁴¹Am, ¹³³Ba, ¹⁵²Eu, and ¹³⁷Cs) to measure the MAC for the prepared glasses. The experimental data were compared with the theoretical results obtained from the XCOM, and it was shown that for all samples at all tested energies, the relative deviation between the samples is less than 3%. This finding signifies that the experimental data can adequately be used to evaluate the shielding ability of the glasses. The MAC of the sample with x = 25 wt % was compared with different lead borate glasses and the results indicated that the present sample has high attenuation which is very close to commercial lead borate glasses. We determined the transmission factor (TF), and found that it is small at low energies and increases as the energy increases. The addition of Bi₂O₃ leads to reduction in the TF values, which improves the shielding performance of the glass system. The half value layer (HVL) of the BCrBi-10 sample was 0.400 cm at 0.595 MeV, 1.619 cm at 0.2447 MeV, and 4.946 cm at 1.4080 MeV. Meanwhile, the HVL of the BCrBi-20 sample is equal to 0.171 and 4.334 cm at 0.0595 and 1.4080 MeV, respectively. The HVL data emphasize that higher energy photons tend to penetrate through the glasses with greater ease than lower energy photons. Furthermore, the fast neutron removable cross section (FNRC) was determined for the present samples and compared with lead borate glass and concrete, and the results showed a remarkable superiority of the bismuth borate glass samples.     

The Vital Role of La2O3 on the La2O3-CaO-B2O3-SiO2 Glass System for Shielding Some Common Gamma Ray Radioactive Sources

The role La₂O₃ on the radiation shielding properties of La₂O₃-CaO-B₂O₃-SiO₂ glass systems was investigated. The energies were selected between 0.284 and 1.275 MeV and Phy-X software was used for the calculations. BLa10 glass had the least linear attenuation coefficient (LAC) at all the tested energies, while BLa30 had the greatest, which indicated that increasing the content of La₂O₃ in the BLa-X glasses enhances the shielding performance of these glasses. The mass attenuation coefficient (MAC) of BLa15 decreases from 0.150 cm²/g to 0.054 cm²/g at energies of 0.284 MeV and 1.275 MeV, respectively, while the MAC of BLa25 decreases from 0.164 cm²/g to 0.053 cm²/g for the same energies, respectively. At all energies, the effective atomic number (Z_eff) values follow the trend BLa10 < BLa15 < BLa20 < BLa25 < BLa30. The half value thickness (HVL) of the BLa-X glass shields were also investigated. The minimum HVL values are found at 0.284 MeV. The HVL results demonstrated that BLa30 is the most space-efficient shield. The tenth value layer (TVL) results demonstrated that the glasses are more effective attenuators at lower energies, while decreasing in ability at greater energies. These mean free path results proved that increasing the density of the glasses, by increasing the amount of La₂O₃ content, lowers MFP, and increases attenuation, which means that BLa30, the glass with the greatest density, absorbs the most amount of radiation.     

Detailed Inspection of γ-ray,Fast and Thermal Neutrons Shielding Competence of Calcium Oxide or Strontium Oxide Comprising Bismuth Borate Glasses

For both the B₂O₃-Bi₂O₃-CaO and B₂O₃-Bi₂O₃-SrO glass systems, γ-ray and neutron attenuation qualities were evaluated. Utilizing the Phy-X/PSD program, within the 0.015–15 MeV energy range, linear attenuation coefficients (µ) and mass attenuation coefficients (μ/ρ) were calculated, and the attained μ/ρ quantities match well with respective simulation results computed by MCNPX, Geant4, and Penelope codes. Instead of B₂O₃/CaO or B₂O₃/SrO, the Bi₂O₃ addition causes improved γ-ray shielding competence, i.e., rise in effective atomic number (Z_eff) and a fall in half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP). Exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) were derived using a geometric progression (G–P) fitting approach at 1–40 mfp penetration depths (PDs), within the 0.015–15 MeV range. Computed radiation protection efficiency (RPE) values confirm their excellent capacity for lower energy photons shielding. Comparably greater density (7.59 g/cm³), larger μ, μ/ρ, Z_eff, equivalent atomic number (Z_eq), and RPE, with the lowest HVL, TVL, MFP, EBFs, and EABFs derived for 30B₂O₃-60Bi₂O₃-10SrO (mol%) glass suggest it as an excellent γ-ray attenuator. Additionally, 30B₂O₃-60Bi₂O₃-10SrO (mol%) glass holds a commensurably bigger macroscopic removal cross-section for fast neutrons (Σ_R) (=0.1199 cm⁻¹), obtained by applying Phy-X/PSD for fast neutrons shielding, owing to the presence of larger wt% of ‘Bi’ (80.6813 wt%) and moderate ‘B’ (2.0869 wt%) elements in it. 70B₂O₃-5Bi₂O₃-25CaO (mol%) sample (B: 17.5887 wt%, Bi: 24.2855 wt%, Ca: 11.6436 wt%, and O: 46.4821 wt%) shows high potentiality for thermal or slow neutrons and intermediate energy neutrons capture or absorption due to comprised high wt% of ‘B’ element in it.     

Understanding the Effect of Introducing Micro- and Nanoparticle Bismuth Oxide (Bi2O3) on the Gamma Ray Shielding Performance of Novel Concrete

The aim of this study is to investigate the radiation shielding properties of novel concrete samples with bulk Bi₂O₃ and Bi₂O₃ nanoparticles (Bi₂O₃ NP) incorporated into its composition. The mass attenuation coefficient of the concrete samples without Bi₂O₃ and with 5 and 7 wt% bulk Bi₂O₃ were experimentally determined and were compared against values obtained using the XCOM and Geant4 simulations. Both methods greatly agree with the experimental values. The linear attenuation coefficients (LAC) of blank concrete (C-0), concrete with 5% bulk Bi₂O₃ (C-B5), and concrete with 5% nanoparticle Bi₂O₃ (C-N5) were determined and compared at a wide energy range. We found that the LAC follows the trend of C-0 < C-B5 < C-N5 at all the tested energies. Since both C-B5 and C-N5 have a greater LAC than C-0, these results indicate that the addition of Bi₂O₃ improves the shielding ability of the concretes. In addition, we investigated the influence of nanoparticle Bi₂O₃ on the LAC of the concretes. The half-value layer (HVL) for the concretes with bulk Bi₂O₃ and Bi₂O₃ nanoparticles is also investigated. At all energies, the C-0 has the greatest HVL, while C-N15 has the least. Thus, C-N15 concrete is the most space efficient, while C-0 is the least space efficient. The radiation protection efficiency (RPE) of the prepared concretes was found to decrease with increasing energy for all five samples. For C-0, the RPE decreased from 63.3% at 0.060 MeV to 13.48% at 1.408 MeV, while for C-N15, the RPE decreased from 87.9 to 15.09% for the same respective energies. Additionally, C-N5 had a greater RPE than C-B5, this result demonstrates that Bi₂O₃ NP are more efficient at shielding radiation than bulk Bi₂O₃.     

Investigation of the Gamma-ray Shielding Performance of CuO-CdO-Bi2O3 Bentonite Ceramics

The purpose of this research is to identify the radiation shielding capability of ceramics adding CuO, CdO, and Bi₂O₃ with diverse wt (%). The chemical compositions of the raw ceramics were documented through Energy Dispersive X-ray “EDX” techniques. For aesthetic appeal and solidification, CuO has been chosen to be added to ceramic. Moreover, in the interest of increasing the radiation shielding ability, the high atomic number and density of both CdO and Bi₂O₃ were suggested for the raw ceramics. To obtain the morphological features of the prepared ceramic samples, a Scanning Electron Microscope, or SEM, was utilized. To verify the experimental results, the MCA value obtained from the Phy-X software was compared to the experimental value collected from the HPGe detector. At energies 0.06 MeV, 0.662 MeV, 1.173 MeV, and 1.333 MeV the linear and mass attenuation coefficients of the prepared ceramics have been measured using a high purity germanium “HPGe” detector as well as three different point sources. Moreover, the relationship between ln(I) and the thickness of the ceramics has been presented here, and the comparison between the LAC of the prepared ceramics with other materials has also been displayed. Bentonite ceramic containing CuO (15 mol %)-CdO (15 mol %)-Bi₂O₃ (20 mol %) with density 3.6 showed the lowest HVL, MFP, and TVL at all studied energies, yet pure Bentonite ceramic containing only CuO (50 mol %), having density 3.4, presented the greatest values. Hence, it can be concluded that the addition of CdO and Bi₂O₃ enhances the radiation shielding ability.     

Trivalent Ions and Their Impacts on Effective Conductivity at 300 K and Radio-Protective Behaviors of Bismo-Borate Glasses: A Comparative Investigation for Al,Y, Nd,Sm, Eu

We aimed to determine the contribution of various trivalent ions like Al and rare-earths (Y, Nd, Sm, Eu) on resistance behaviors of different types of bismo-borate glasses. Accordingly, eight different bismuth borate glasses from the system: 40Bi₂O₃–59B₂O₃–1Tv₂O₃ (where Tv = Al, Y, Nd, Sm, and Eu) and three glasses of (40Bi₂O₃–60B₂O₃; 37.5Bi₂O₃–62.5B₂O₃; and 38Bi₂O₃–60B₂O₃–2Al₂O₃) compositions were extensively investigated in terms of their nuclear attenuation shielding properties, along with effective conductivity and buildup factors. The Py-MLBUF online platform was also utilized for determination of some essential parameters. Next, attenuation coefficients, along with half and tenth value layers, have been determined in the 0.015 MeV–15 MeV photon energy range. Moreover, effective atomic numbers and effective atomic weight, along with exposure and energy absorption buildup factors, were determined in the same energy range. The result showed that the type of trivalent ion has a direct effect on behaviors of bismo-borate glasses against ionizing gamma-rays. As incident photon energy increases, the effective thermal conductivity decreases rapidly, especially in the low energy range, where photoelectric effects dominate the photon–matter interaction. Sample 8 had the minimum heat conductivity at low photon energies; our findings showed that Eu-reinforced bismo-borate glass composition, namely 40Bi₂O₃–59B₂O₃–1Eu₂O₃, with a glass density of 6.328 g/cm³ had superior gamma-ray attenuation properties. These outcomes would be useful for the scientific community to observe the most suitable additive rareearth type and related glass composition for providing the aforementioned shielding properties, in terms of needs and utilization requirements.     

Thermal Stability,Optical Properties,and Gamma Shielding Properties of Tellurite Glass Modified with Potassium Chloride

The synthesized glass system with a composition of (80-x) TeO₂-10P₂O₅-10Nb₂O₅-xKCl mol% (where x = 5, 10, 15, 20, and 25) was successfully fabricated. The density (ρ) and molar volume (V_m) have been calculated. The investigated glasses were characterized using different analysis methods (differential thermal analysis (DTA) and UV-VIS-NIR spectroscopy). The radiation shielding effectiveness of the synthesized glass system was evaluated using different shielding parameters, such as mass and linear attenuation coefficients (MAC, LAC), half-value layer (HVL), mean free path (MFP), effective atomic number (Z_eff), and effective electron number (N_eff). The results showed that with the increasing potassium chloride (KCl) concentration and decreasing tellurium oxide (TeO₂) concentration, the density, refractive index, Urbach energy (E_u), and glass transition temperature (T_g) decreased, while the optical energy gap (E_opt) and thermal stability increased. As the KCl concentration increases, the values of MAC, LAC, and Z_eff increase in the following order: TPNK5 % > TPNK10 % > TPNK15 % > TPNK20 % > TPNK25 %. Additionally, the shielding effectiveness of TPNK glass system showed good performance compared with some standard materials. The synthesized glass with a minimum KCl content has both good shielding effectiveness and good optical properties, in addition to reasonable thermal stability, which makes it suitable for shielding and optical applications.     

Evaluation of the Radiation Shielding Properties of a Tellurite Glass System Modified with Sodium Oxide

In this study, the X-ray and gamma attenuation characteristics and optical properties of a synthesized tellurite–phosphate–sodium oxide glass system with a composition of (85 − x)TeO₂–10P₂O₅–xNa₂O mol% (where x = 15, 20, and 25) were evaluated. The glass systems we re fabricated by our research group using quenching melt fabrication. The shielding parameters of as-synthesized systems, such as the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), effective atomic number (Z_eff), half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and effective electron density (N_eff) in a wide energy range between 15 keV and 15 MeV, were estimated using well-known PHY-X/PSD software and recently developed MIKE software. Herein, the optical parameters of prepared glasses, such as molar volume (V_M), oxygen molar volume (V_O), oxygen packing density (OPD), molar polarizability (αm), molar refractivity (R_m), reflection loss (R_L), and metallization (M), were estimated using MIKE software. Furthermore, the shielding performance of the prepared glasses was compared with that of commonly used standard glass shielding materials. The results show that the incorporation of sodium oxide into the matrix TeO₂/P₂O₅ with an optimum concentration can yield a glass system with good shielding performance as well as good optical and physical properties, especially at low photon energy.     

Study on Radiation Shielding Properties of New Barium-Doped Zinc Tellurite Glass

This study aimed to investigate the effect of BaF₂ on the radiation-shielding ability of lead telluride glass. A physical radioactive source was used to estimate the mass attenuation coefficient (μ_m) of the 60TeO₂-20PbO-(20-x)ZnO-xBaF₂ glass system (where x = 1,2,3,5,6,7,9 mol%). We tested the μ_m values at seven energies (0.059, 0.081, 0.122, 0.356, 0.662, 1.173, 1.332 MeV). To determine the accuracy of the obtained results, we compared the experimental data with the data calculated using the XCOM software. The experimental values obtained for the selected lead telluride glasses at different concentrations of BaF₂ are in good agreement with the results of XCOM at all energies. The addition of BaF₂ increased the μ_m value of the sample. At the same time, the half-value layer (HVL), mean free path (MFP), effective atomic number (Z_eff), and fast neutron removal cross-section (RCS) of the glass were studied. With the increase in the BaF₂ content, the HVL value and MFP value of the glass decreased, and the Z_eff value and RCS increased, indicating that the addition of BaF₂ enhanced the radiation-shielding performance of the glass.     

The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte-Carlo Simulation and Theoretical Study

The radiation shielding competence was examined for a binary glass system xLa₂O₃ + (1 − x) TeO₂ where x = 5, 7, 10, 15, and 20 mol% using MCNP-5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Z_eq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters.     

Influence of ZnF2 and WO3 on Radiation Attenuation Features of Oxyfluoride Tellurite WO3-ZnF2-TeO2 Glasses Using Phy-X/PSD Software

The radiation shielding features of the ternary oxyfluoride tellurite glasses were studied by calculating different shielding factors. The effect of the TeO₂, WO_3, and ZnF₂ on the tested glass system’s attenuating performance was predicted from the examination. The mass attenuation coefficient (µ/ρ) values for the oxyfluoride tellurite glasses depend highly on the concentration of WO_3, as well as ZnF₂. All the present ZnFWTe1-ZnFWTe5 samples have higher µ/ρ values than that of the pure TeO₂ glass at all energies. For the samples with a fixed content of WO₃, the replacement of TeO₂ by ZnF₂ increases the µ/ρ, while for the glasses with a fixed content of TeO₂, the replacement of WO₃ by ZnF₂ results in a decline in the µ/ρ values. The results revealed that ZnFWTe4 has the lowest linear attenuation coefficient (µ) among the oxyfluoride tellurite glasses, whereby it has a slightly higher value than pure TeO₂ glass. The maximum effective atomic number (Z_eff) is found at 0.284 MeV and varied between 31.75 and 34.30 for the tested glasses; it equaled to 30.29 for the pure TeO₂ glass. The half-value layer (HVL) of the glasses showed a gradual decline with increasing density. The pure TeO₂ was revealed to have thicker HVL than the selected oxyfluoride tellurite glasses. A 1.901-cm thickness of the sample, ZnFWTe1, is required to decrease the intensity of a photon with an energy of 0.284 MeV to one-tenth of its original, whereas 1.936, 1.956, 2.212, and 2.079 cm are required for glasses ZnFWTe2, ZnFWTe3, ZnFWTe4, and ZnFWTe5, respectively.     

Structural,Thermal and Dielectric Properties of Low Dielectric Permittivity Cordierite-Mullite-Glass Substrates at Terahertz Frequencies

Glass–ceramic composites containing cordierite, mullite, SiO₂ glass and SiO₂-B₂O₃-Al₂O₃-BaO-ZrO₂ glass were fabricated in a process comprising solid state synthesis, milling, pressing and sintering. Thermal behavior, microstructure, composition and dielectric properties in the Hz-MHz, GHz and THz ranges were examined using a heating microscope, differential thermal analysis, thermogravimetry, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction analysis, impedance spectroscopy, transmission method and time domain spectroscopy (TDS). The obtained substrates exhibited a low dielectric permittivity of 4.0–4.8. Spontaneously formed closed porosity dependent on the sintering conditions was considered as a factor that decreased the effective dielectric permittivity.     

Impact of ZnO Modifier Concentration on TeO2 Glass Matrix for Optical and Gamma-Ray Shielding Capabilities

This study carried out a comparison of the optical and gamma ray shielding features of TeO₂ with and without ZnO modifier concentration. Incorporating ZnO into the TeO₂ network reduces the indirect band gap from 3.515–3.481 eV. When ZnO is added, refractive indices, dielectric constants, and optical dielectric constants rise from 2.271–2.278, 5.156–5.191, and 4.156–4.191 accordingly. The transmission coefficient and reflection loss are in direct opposition to each other. With increasing ZnO concentration in the selected glasses, the values of molar refractivity and molar polarizability decrease from 18.767–15.018 cm³/mol and from 7.444 × 10⁻²⁴–5.957 × 10⁻²⁴ cm³, respectively, while the electronic polarizability rises from 8.244 × 10²⁴–8.273 × 10²⁴, correspondingly. As expected by the metallization values, the glass systems are non-metallic. The linear attenuation coefficients (LAC) of the studied glass samples ensue through enhancing the photon energy range 0.0395–0.3443 MeV. There is a very slow decrease in the LAC from an energy of 0.1218–0.3443 MeV, yet there is a sharp decrease from an energy of 0.0401–0.0459 MeV. According to the obtained values of numerous shielding parameters such as LAC, MAC, HVL, MFP, and Z_eff sample, Zn30 has shown the best radiation shielding ability comprising other studied samples.     

Experimental and Theoretical Study of Radiation Shielding Features of CaO-K2O-Na2O-P2O5 Glass Systems

The gamma radiation shielding ability for CaO-K₂O-Na₂O-P₂O₅ glasses were experimentally determined between 0.0595 and 1.41 MeV. The experimental MAC results were compared with theoretical results obtained from the XCOM software to test the accuracy of the experimental values. Additionally, the effect of increasing the P₂O₅ in the glass composition, or reducing the Na₂O content, was evaluated at varying energies. For the fabricated glasses, the experimental data strongly agreed with the XCOM results. The effective atomic number (Z_eff) of the fabricated glasses was also determined. The Z_eff values start out at their maximum (12.41–12.55) at the lowest tested energy, 0.0595 MeV, and decrease to 10.69–10.80 at 0.245 MeV. As energy further increases, the Z_eff values remain almost constant between 0.344 and 1.41 MeV. The mean free path (MFP) of the fabricated glasses is investigated and we found that the lowest MFP value occurs at the lowest tested energy, 0.0595 MeV, and lies within the range of 1.382–1.486 cm, while the greatest MFP can be found at the highest tested energy, 1.41 MeV, within the range of 8.121–8.656 cm. At all energies, the KCNP40 sample has the lowest MFP, while the KCNP60 sample has the greatest. The half value layer (HVL) for the KCNP-X glasses is determined. For all the selected energies, the HVL values follow the order of KCNP40 < KCNP45 < KCNP50 < KCNP55 < KCNP60. The HVL of the KCNP50 sample increased from 0.996 to 2.663, 3.392, 4.351, and 5.169 cm for energies of 0.0595, 0.245, 0.444, 0.779, and 1.11 MeV, respectively. The radiation protection efficiency (RPE) results reveal that decreasing the P₂O₅ content in the glasses improves the radiation shielding ability of the samples. Thus, the KCNP40 sample has the best potential for photon attenuation applications.     

Structure and Dielectric Behavior of Yb2O3-MgO Co-Doped 0.92BaTiO3-0.08(Na0.5Bi0.5)TiO3 Ferroelectric Relaxor

Dielectric properties and structure of 0.015Yb₂O₃-xMgO doped 0.92BaTiO₃-0.08(Na_0.5Bi_0.5)TiO₃ ceramics with x = 0.0–0.025 have been investigated. As Yb₂O₃-MgO was added into the BT-NBT, the phase changes from tetragonal to pseudo-cubic, with the tetragonality c/a decreases from 1.011 to 1.008 and XRD peaks broadened. The combined study of XRD and TEM image revealed a formation of core–shell structure in grains with core of 400–600 nm and the shell of a thickness 60–200 nm. There is a slowly phase transition against temperature from the variable temperature Raman analysis. The ferroelectric relaxor peak of BT-NBT decreases from ~4000 to ~2000 and a new broad dielectric peak with an equivalent maximum (ε_r′~2300) appears in the temperature dependent dielectric constant curve (ε_r′-T), which produces a flat ε_r′-T curve. Sample 0.92BaTiO₃-0.08(Na_0.5Bi_0.5)TiO₃-0.015Yb₂O₃-0.005 MgO and 0.92BaTiO₃-0.08(Na_0.5Bi_0.5)TiO₃-0.015Yb₂O₃-0.01MgO give a ε_r′ variation within ±14% and ±10% in 20–165 °C. The core–shell microstructure should take account for the flattened ε_r′–T behavior of these samples.     

The Effect of ZnO,MgO, TiO2, and Na2O Modifiers on the Physical,Optical, and Radiation Shielding Properties of a TeTaNb Glass System

Novel glass samples with the composition 75TeO₂–5Ta₂O₅–15Nb₂O₅–5x (where x = ZnO, MgO, TiO₂, or Na₂O) in mole percent were prepared. The physical, optical, and gamma radiation shielding properties of the glass samples were studied over a wide energy spectrum ranging between 0.015 and 20 MeV. The glasses’ UV–vis spectra were utilized to evaluate the optical energy gap and refractive index. Glass samples had a refractive index ranging from 2.2005 to 2.0967. The results showed that the sample doped with zinc oxide (ZnO) recorded the highest density (ρ_glass), molar polarizability (α_m), molar refraction (Rm), refractive index (n), and third-order nonlinear optical susceptibility (χ³) and the lowest optical energy gap (E_opt) among the samples under investigation. When comparing the current glass system with various standard glass shielding materials, the prepared glass system showed superior shielding performance at energies ranging between 40 and 85 keV. These findings indicate that the prepared glass systems can be used in diagnostic X-rays, especially in dental applications.     

Influence of N2 Partial Pressure on Structure and Mechanical Properties of TiAlN/Al2O3 Multilayers

TiAlN/Al₂O₃ multilayers with different Ar/N₂ ratios were deposited on Sisubstrates in different N₂ partial pressure by magnetron sputtering. The crystalline and multilayer structures of the multilayers were determined by a glancing angle X-ray diffractometer (XRD). A nanoindenter was used to evaluate the hardness, the elastic modulus and scratch scan of the multilayers. The chemical bonding was investigated by a X-ray Photoelectron Spectroscopy (XPS). The maximum hardness (36.3 GPa) and elastic modulus (466 GPa) of the multilayers was obtained when Ar/N₂ ratio was 18:1. The TiAlN/Al₂O₃ multilayers were crystallized with orientation in the (111) and (311) crystallographic planes. The multilayers displayed stably plastic recovery in different Ar/N₂ ratios. The scratch scan and post scan surface profiles of TiAlN/Al₂O₃ multilayers showed the highest critical fracture load (L_c) of 53 mN for the multilayer of Ar/N₂ = 18:1. It indicated that the multilayer had better practical adhesion strength and fracture resistance.     

Postperovskite phase equilibria in the MgSiO3–Al2O3 system

We investigate high-P,T phase equilibria of the MgSiO₃–Al₂O₃ system by means of the density functional ab initio computation methods with multiconfiguration sampling. Being different from earlier studies based on the static substitution properties with no consideration of Rh₂O₃(II) phase, present calculations demonstrate that (i) dissolving Al₂O₃ tends to decrease the postperovskite transition pressure of MgSiO₃ but the effect is not significant (≈-0.2 GPa/mol% Al₂O₃); (ii) Al₂O₃ produces the narrow perovskite+postperovskite coexisting P,T area (≈1 GPa) for the pyrolitic concentration (x_Al2O3 ≈6 mol%), which is sufficiently responsible to the deep-mantle D″ seismic discontinuity; (iii) the transition would be smeared (≈4 GPa) for the basaltic Al-rich composition (x_Al2O3 ≈20 mol%), which is still seismically visible unless iron has significant effects; and last (iv) the perovskite structure spontaneously changes to the Rh₂O₃(II) with increasing the Al concentration involving small displacements of the Mg-site cations.