Fast Neutron Attenuation Research Articles

Evaluation of radiation shielding effectiveness of some metallic alloys used in the nuclear facilities

Abstract Several nuclear shielding parameters were evaluated for stainless steel grades 304, 304 L, 316, and 316 L. The effective atomic number Zeff, mean free path (MFP), effective electron density Neff, half-value layer (HVL), and effective conductivity (Ceff) of the investigated alloys were evaluated via the mass attenuation coefficient (µ/ρ). The mass attenuation (µ/ρ) coefficients were computed for gamma-ray photons in the energy range 15 keV to 15 MeV using Phy-X/PSD program. Fast neutron attenuation was analyzed by computing the removal cross-sections (SR) using partial density method. The obtained results by Phy-X/PSD program were validated using Monte Carlo (MCNP4C) code. The stopping power of these alloys against e-1/H1/He+2 ions was evaluated using the ESTAR and SRIM Monte Carlo code, considering total stopping power (TSP) and projected range (PR). Furthermore, the transmitted neutron fraction at different neutron energies were calculated using Neutron Calculatro-V2 code for thermal neutrons (of energy 25.4 eV) and fast neutrons (with energies of 4 and 4.5 MeV). The obtained results showed that 316L alloy possesses good protection performance against gamma photons, charged particles, fast and thermal neutrons compared with other investigated alloys. Comparison of the calculated values revealed good agreement between Phy-X/PSD and MCNP4b. This work should be informative for the potential uses of these materials in the nuclear industry to build effective radiation shielding.

Tailoring the FTIR, magnetic properties and neutron attenuation capacity of borosilicate glass: Role of Co3O4

For Co3O4-reinforced borosilicate glasses, the effects of Co3O4 on the physical, FTIR, magnetic, γ-ray accumulation factors, and fast neutron attenuation capability were assessed. The nominal composition created using the traditional melt quench process was 15SiO2–20BaF2–20Na2O-(45-X)B2O3-XCo3O4, where X = 0.0 (Co-0.0) – 2.0 (Co-2.0) mol%. The Co-X samples amorphous condition as determined by XRD measurements. Specimen's density increased to 2.90 g/cm3 from 2.81 g/cm3. FTIR measurements verified that there was a conversion of [BO3] to [BO4] groups in the glass networks. As the Co3O4 concentration increased in the glass networks, the saturation magnetization decreased, while the coercivity increased. As photon energy rose, exposure and energy absorption accumulation factors got better. The glass sample designated as Co-2.0 demonstrated the lowest values of both relaxation length (λFNRCS) and half value layer (HVLFNRCS). The sample with code Co-2.0 has the best defense against radiation from γ-ray/fast neutrons. The findings verify that the Co-X glasses under investigation are suitable materials for applications involving magnetic and γ-ray/neutron shielding.

Tailoring optimal KERMA, projected range, and mass stopping power, and gamma-ray shielding capabilities through BaO/ZnO/CdO/SrO incorporation into Na2O–SiO2 glasses

This study explores the radiation shielding potential of Na2O–SiO2 glass matrices doped with BaO, ZnO, CdO, and SrO, analysed across a broad energy spectrum. The research employed various computational tools such as Phy-X/PSD and PAGEX codes to calculate various shielding parameters, including Kinetic Energy Released in Material (KERMA), mass stopping power, fast neutron, and gamma-ray attenuation properties. Among the glass samples, S3, with its BaO content, exhibited the most advantageous properties in terms of radiation attenuation. The results showed that S3 has the lowest Half Value Layer (HVL) of 0.032 cm at 0.015 MeV and the highest KERMA value, peaking at 0.3 MeV with 0.18 MeV/g. The mass stopping power values for alpha particles in the S3 sample showed a pronounced peak at 0.7 MeV, reaching 150 MeV cm2/g, indicating superior energy absorption. The S3 sample, composed of 20% Na2O, 20% BaO, and 60% SiO2, demonstrated the highest density (i.e., 3.225 g/cm³) and effective atomic number (i.e., 17.5), which contributed to its superior shielding performance. The study's findings show that the careful manipulation of glass composition, particularly through the incorporation of high-atomic-number oxides, can significantly enhance shielding effectiveness. It can be concluded that the S3 glass sample would be an optimal configuration for practical applications in radiation protection, where the Na2O–SiO2 glass matrices doped with BaO in terms of optimal material properties.

Enhancing the radiation shielding performance of polyepoxide composites based on cement bypass dust

In this study, radiation shielding composite materials were created by combining epoxy with cement bypass dust (CBPD) at different weight percentages (0%, 10%, 20%, and 30%). The solution casting technique was employed to construct these materials. The FTIR spectra confirmed the formation of the composites and the production of complexes. The morphology and elemental content of the produced composite samples were illustrated using SEM pictures and EDX spectra. In addition, the research findings demonstrated that the composites exhibited improved resistance to changes in temperature as the loading of CBPD increased. The gamma-ray attenuation coefficients of composites consisting of Epoxy + x% CBPD exhibited an increase, along with an increase in the neutron removal cross-section. However, there was a gradual increase in both the mean free path (MFP) as well as the half value layer (HVL) with increasing energy. Additionally, the experimental and theoretical data for attenuation parameters were compared using the Phy-X/PSD software. The relationship between the effective atomic and electron numbers of the Epoxy + x% CBPD composites has been studied. The values of fast and thermal neutron attenuation were analyzed using the NGCal software. In general, these composites are appropriate for use in radiation shielding applications.

Effect of ZrO2 on physical and radiation shielding properties of tellurium −lead- calcium −borate (TPCB)glass system

This research investigates the impact of adding Zirconia (ZrO2) to tellurium-lead-borate glasses, focusing on how it affects their physical, optical, and radiation shielding properties, particularly against gamma-rays and neutrons. Key parameters for gamma-ray shielding (mass attenuation coefficient (µm), effective atomic numbers (Zeff), and effective electron densities (Neff)) were measured across an energy range of 0.080 to 2.614 MeV. Notably, excellent agreement (within 0.5 %) was observed between the measured and calculated µm values. For slow neutron attenuation measurements, we employed a 241Am-Be neutron source in conjunction with a BF3 detector. Fast neutron attenuation was assessed using the NXCOM software to determine the effective macroscopic removal cross-section (ΣR). The addition of Zirconia notably enhanced the glass density (∼6.8 %) and its ability to shield against gamma-rays (∼10 %) and slow neutrons (∼71 %). However, this improvement comes with a slight trade-off: a decrease of approximately 1.5 % in fast neutron attenuation was observed. This trade-off between shielding effectiveness for different radiation types warrants further investigation to optimize glass compositions, considering the desired balance between shielding performance across various radiation spectrums.

Novel 3D-Printed lead-free radiation protection apron in the medical X-ray and thermal neutron energy range

In this study, we employed 3D printing technology to fabricate poly lactic acid (PLA) polymer samples infused with gadolinium oxide nanoparticles at additive rates of 10% and 20%. The objective was to explore their potential as radiation shielding aprons within the medical X-ray and thermal neutron energy spectrum. To facilitate comparisons, a PLA polymer sample with no additive was also produced. The homogeneity and well-defined structures of the PLA samples were observed using SEM and EDS analyses. Additionally, the excellent thermal stability of the proposed test samples was reported. In terms of gamma-ray shielding, there is a remarkable consistency between experiment, theory and simulation outcomes with a maximum discrepancy of approximately 5%. P-PLA-Gd20 sample exhibits attenuation capabilities against X-rays to a level that could serve as an alternative to lead. Additionally, the thermal and fast neutron attenuation effectiveness of the prepared samples were determined. A shielding effectiveness of 100% against thermal neutrons was achieved using a 10 mm sample thickness and the P-PLA-Gd20 sample. The findings consistently highlight the efficacy of the proposed polymer sample with a 20% gadolinium oxide nanoparticle additive, positioning it as a viable and promising alternative to traditional lead aprons.

Physical, structural and nuclear radiation shielding behavior of Ni–Cu–Zn Fe2O4 ferrite nanoparticles

In this study, Ni–Cu–Zn Fe2O4 ferrite nanoparticles have successfully been synthesized utilizing the Co-precipitation technique. The primary objectives encompassed elucidating phase purity, discerning functional groups, scrutinizing surface morphology, and conducting structural analyses. To accomplish these objectives, a battery of advanced characterization techniques was employed, including power X-ray diffraction, Transmission infrared spectroscopy, UV–Visible spectrophotometer, and Scanning electron microscopy. Furthermore, the investigation was extended to the assessment of the gamma ray shielding properties exhibited by the synthesized Ni–Cu–Zn Fe2O4 nanoparticles, spanning an energy range from 122 keV to 1330 keV. This evaluation was carried out through the utilization of a NaI(Tl) detector coupled with a PC-based multichannel analyzer. The acquired data were meticulously compared with established theoretical value. The results of this study point to a viable route for using this simple, cost-effective, and low-temperature synthesis approach to create nanomaterials suited for gamma ray shielding applications, as well as broader radiation protection. This novel technique has the potential to significantly improve radiation shielding technology. Along with this fast neutron attenuation capability of this prepared ferrite samples have been studied in terms of fast neutron removal cross section.

Radiation shielding effectiveness, structural, and mechanical properties of HDPE/B4C composites reinforced with Fe2O3-Al2O3-Al-Fe fillers

The fast neutron and gamma-ray attenuation properties of pure high-density polyethylene and its composites were investigated, including 90 HDPE/10 B4C (wt%) and 60 HDPE/10 B4C/30X (wt%) (Where X represents iron oxide, aluminum oxide, iron, and aluminum). The examined samples were analyzed using a scanning electron microscope, and their mechanical properties were assessed. The composite of 60 HDPE/10 B4C/30 α-Fe2O3 (wt%) shows better mechanical properties than those of other composites under investigation. 239Pu–Be was used as a source of fast neutrons with a neutron yield of 1.7 × 106 n s−1 and was detected by the Stilbene scintillator. Neutron removal cross-section with dependent parameters, the mean free path and half-value layer of the prepared composites, were calculated. Furthermore, the gamma-ray transmission through the produced composites has been examined. The composite containing 30% iron oxide exhibited superior shielding characteristics for neutrons and gamma rays compared to the other analyzed samples. The computed values of the shielding characteristics indicate that the produced composites are highly effective for shielding fast neutrons and gamma rays in radiation facilities.

On β-titanium alloys: tailoring gamma-ray, and neutron transmission properties for nuclear and biomedical applications

This study explores the gamma-ray and neutron transmission properties of β-Titanium alloys pivotal for their performance in nuclear and biomedical applications. Utilizing the Monte Carlo N-Particle (MCNP 6.3) simulations, we analyzed a spectrum of Ti-based alloys modified with elements like molybdenum (Mo), zirconium (Zr), niobium (Nb), and hafnium (Hf) to determine their radiation attenuation properties. Key parameters such as mass and linear attenuation coefficients, half-value layers, exposure buildup factors, and fast neutron effective removal cross-section values were computed, revealing significant enhancements in attenuation with the addition of high-Z elements. Specifically, alloys like Ti50Hf50 and (TiZr)40Cu60 exhibited superior photon and fast neutron attenuation due to their high-Z constituents. For instance, Ti50Hf50 showed a mass attenuation coefficient of 0.217 cm2/g and a half-value layer of 2.97 cm at 0.1 MeV photon energy, while (TiZr)40Cu60 demonstrated similar performance with a mass attenuation coefficient of 0.198 cm2/g and a half-value layer of 3.26 cm. These alloys also exhibited effective neutron removal cross-section values of 0.115 cm−1 and 0.130 cm−1, respectively. Alloys with lower-Z elements showed less attenuation, which may be beneficial in scenarios requiring reduced radiographic contrast in biomedical applications. The MCNP outcomes were in strong agreement with standard data, affirming the accuracy of computational methods in predicting material behavior. In conclusion, tailored alloy development is crucial for improving radiation shielding and diagnostic visualization, with broader implications for patient safety and treatment efficacy.

Characterizing unsaturated polyester composites for fast neutron attenuation

Characterizing unsaturated polyester composites for fast neutron attenuation

Fast neutrons and gamma rays shielding properties for some nylon composite

In this study, The removal parameters of macroscopic fast neutron cross-section, linear gamma ray attenuation, mean free path, and half-value layer (half-value thickness) were calculated for a polymer composite containing nylon 6 as a base material and starch powder, silica oxide, and calcium carbonate as reinforcement materials for different energies (0.05, 0.1, 0.3, 0.6, 0.8, 1, 3, 7, 10, 15) and for various concentrations (5, 10, 15, 20, 25). We used the x-com program to calculate gamma ray attenuation values. The results showed that the macroscopic cross-section of fast neutron attenuation and the linear attenuation coefficient for gamma rays increase with increasing reinforcement materials concentration, while the values of half-value layer decrease with increasing concentrations. When the energy increases, the half-value layer and the mean free path also increase, however, the values of the linear attenuation coefficient decrease.

Evaluation of neutron shielding performance of cementless binder manufactured with desalination reject brine

This study investigated the feasibility of desalination reject brine as a new water resource for the nuclear construction industry by evaluating the thermal neutron shielding properties of Ca(OH)2–Na2CO3-activated fly ash (FA-NC) binder manufactured with reject brine since the high chloride concentration is believed to promote neutron shielding performance. High Cl− concentration encouraged rapid and greater early-age strength development of FA-NC binder mixed with reject brine, which is the main mechanism of the accelerator. A series of chemical and microstructural analyzes were conducted, namely, XRD, TG, and MIP tests, to investigate the influence of the reject brine. The use of reject brine remarkably improved the thermal neutron attenuation performance of the FA-NC binder and achieved 98.76 % of thermal neutron shielding efficiency. Furthermore, the reject brine provided an increased efficacy in fast neutron attenuation. To further analyze the practical application potential, a 190 × 90 × 57 mm sized brick sample was made using rejected brine mixed FA-NC binder and tested with the followings: water absorption and TCLP.

Radiation protection efficiency of newly produced W-based alloys: Experimental and computational study

Tungsten based alloy is one of the materials which has great attention and can be used as gamma-ray shields, radiation source collimator, spallation neutron source target, plasma facing materials, etc. The motivation of the study is to produce new tungsten based alloys and determine the radiation protection characteristics of the alloys that can be used for radiation related applications. In this context, five tungsten based alloys (WxTayCr10Ni10Fe10Mo10) were produced and the dependence of radiation shielding ability on the changes in W and Ta concentration was investigated. The photon protection parameters such as linear attenuation coefficients, mass attenuation coefficients, effective atomic number, mean free path, half-value layer, exposure and energy absorption buildup factors, effective conductivity, effective electron number, atomic and electronic cross sections, and fast neutron removal cross-sections of the alloys were determined by Phy-X/PSD code. Additionally, XRD, EPR and SEM-EDS experimental results were evaluated for the investigation of spectroscopic characteristics. The crystallite sizes of the alloys were calculated by Debye-Scherrer method depending on the XRD phases in order to perform the structural characterization. It is concluded that a relationship exists between the crystallite size and photon attenuation. It may be stated that the increase in the amount of W improves the gamma radiation protection efficiency of the alloys. It is also seen that the fast neutron attenuation feature increases proportionally with W content. It is determined that the tungsten based alloys can be used as good radiation protection materials in radiation related applications.

Estimation of neutron and gamma-ray attenuation characteristics of some ferrites: Geant4, FLUKA and WinXCom studies

Ferrites are ceramic oxide materials consisting of mainly iron oxide and they have become massively important materials commercially and technologically, having a multitude of uses and applications. The protection against neutron–gamma mixed radiation is crucial in several nuclear applications. From this standpoint, mass attenuation coefficient, radiation protection efficiency and transmission factor of some ferrites namely barium, strontium, manganese, copper and cadmium ferrite has been computed using Geant4 and FLUKA simulations. Based on the simulated mass attenuation coefficient, other significant parameters such as linear attenuation coefficient, effective atomic and electron number, conductivity, half value layer, and mean free path were calculated for the selected ferrite materials. The validation of Monte Carlo geometry has been provided by comparing the mass attenuation coefficient results with standard WinXCom data. Gamma ray exposure buildup factors were computed using geometric progression fitting formula for the chosen ferrites in the energy range 0.015–15 MeV at penetration depths up to 40 mfp. The findings of the present work reveal that among the studied ferrites, barium ferrite and copper ferrite possess superior gamma ray and fast neutron attenuation capability, respectively. The present work provides a comprehensive investigation of the selected iron oxides in the field of neutron and gamma ray.

Recycling of waste cathode-ray tube glasses as building materials for shielding structures in medical and nuclear facilities

In view of the low market demand and toxic elements contained in cathode ray tubes (CRT), a sustainable method of recycling CRT glasses has become important from the perspectives of waste management and the ecosystem. This research investigated the environmental and economic benefits of the panel (PCRT) and cone (CCRT) glasses, from conventional CRT, as building materials in medical and nuclear facilities. The chemical composition of the two glasses was quantified using X-ray fluorescence (XRF) equipment. The nuclear shielding ability of the CCRT and PCRT was investigated by estimating interaction parameters directly linked to photons, charged particles (CP) (β, H+, He2+, and C6+), fissile neutrons, and thermal neutrons. The mass attenuation coefficients (MAC) of the glasses were determined by FLUKA simulations and XCOM. The CP stopping powers and range were computed using the ESTAR, PSTAR, ASTAR, and SRIM software. The cross sections for fast and thermal neutrons were used to determine the neutron moderating and absorption abilities of the two glasses. The CCRT showed greater gamma, fast neutron, thermal neutron, and CP attenuation capacity relative to the PCRT. The CCRT thus contributes more to the radiation shielding competence of CRT than the PCRT. The photon shielding proficiency of the glasses was found to be superior to many standard shielding materials. Hence, PCRT, CCRT, and therefore CRT could improve the shielding capacity of a medium. The use of CRT glass for producing radiation-protective glasses is a viable way of eradicating waste CRT from the environment.

Analysis of radiation shielding effectiveness of hydride and borohydride metals for nuclear industry

Hydrogenous materials are of great interest in nuclear industry because of the ability of hydrogen to slow-down neutrons. In comparison with common hydrogenous materials, metal hydrides highly enriched with hydrogen at high temperatures and good mechanical properties. This study concerns on evaluation the requirements for photons, charged particles and fast neutrons shielding parameters for several types of hydride and borohydride metals. Firstly, photons shielding ability of these materials were examined using Phy-X/PSD program. Assigning the attenuation factors of photons were evaluated for an energy range (1 keV–100 GeV). Secondly, the charged particle (electron, proton and alpha particle) interactions were examined by using ESTAR (Stopping Powers and Ranges for Electrons) and SRIM (The Stopping and Range of Ions in Matter) programs. Finally, fast neutron attenuation was tested by calculating the removal cross-sections (ΣR) for neutron with energy 4.5 MeV. The dependence of photons, charged particles and fast neutrons parameters on the constituent of tested samples was given and discussed. The obtained results through this work show that, the shielding proficiency parameters depend on the energy of the incident radiation and chemical constituents of the examined materials. As well as, these results showed that BaH2, ZrH2, VH2 and TiH2 samples own a good shielding performance compared to the other investigated samples.

Fabrication and development of neutron shielding materials based on natural rubber and boron carbide

Neutron shielding materials were fabricated based on natural rubber (NR) and boron carbide (B4C) as their main components. Natural rubber, which is abundant in hydrogen, can lower the energy of a neutron. Boron carbide could be utilized as a neutron shielding material due to its high boron content. The shielding materials were fabricated with boron carbide concentrations of 0, 20, 40, 60 parts per hundred rubber (phr), and 50 wt%. Each sample has been fabricated with thicknesses of 5, 10, 15, 20, and 24 mm. The fabricated materials were examined for mechanical and neutron attenuation tests. The Am/Be at the Radiation Measurement Laboratory at the Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University, was used as a neutron source. The results show that boron carbide has the effect of reducing the toughness while increasing the hardness of NR composites. The NR sample of 50 wt% in boron carbide allows only 14.1% of neutron transmission according to fast neutron attenuation tests, which is similar to that of a sample of the commercial product obtained from a Japanese company. Our findings will later be compared to those of a Monte Carlo N-Particle (MCNP) transport code.

Studying of Thermal and Shielding Properties of PVDF (PolyVinyliDene Fluoride) Pipes used in Aqueous Solution Sector

As a result of a fire or explosion in nuclear fuel fabrication facilities two risks to health and safety. Mitigation of fire hazards and radioactive release necessitates the use of fire-resistant and appropriate shielding materials, specifically plastic tubes used in chemical reactions during the conversion process. This paper aims to study the thermal stability, flammability, and shielding properties of polyvinylidene fluoride (PVDF) tubes used in the aqueous solutions sector of the Egypt Fuel Manufacturing Pilot Plant (FMPP), to can replacement the consumed one by another from the local market with the same property. For this purpose, PVDF samples were tested by Energy Dispersive X-ray spectroscopy (EDX) and X-ray direction (XRD). Thermal analysis tests as thermogravimetric analysis (TGA) as well as the derivative of thermogravimetric analysis (DTGA). The ignition test was applied using a limiting oxygen index (LOI), flame chamber (UL/94). 137Cs radioactive source of 5mCi activity was used for gamma shielding properties measurement. Shielding parameters of fast neutrons like removal cross-section and mean free path was calculated. Results of (TGA), showed that PVDF has good thermal stability, where weight loss (about1%) is observed at a temperature above 422ºC. PVDF sample successfully passed the UL-94 H-0 rating with a Limiting Oxygen Index (LOI) of about % 44.8. Also, it has appropriate shielding properties due to the high content of fluorine atoms. PVDF containing Al metal in their composition is more effective for the attenuation of fast neutrons.

Deep Insights into the Radiation Shielding Features of Heavy Minerals in Their Native Status: Implications for Their Physical, Mineralogical, Geochemical, and Morphological Properties

Barite and hematite are the most common heavy-weight minerals applied as aggregates in radiation shielding concrete (RSC). Therefore, to limit the cement consumption and reduce the CO2 emissions accompanying its production, the aim of this study is to use Egyptian barite and hematite minerals in their native status and evaluate their attenuation efficiency against fast neutrons and γ-rays. This was implemented through the measurement of their radiation attenuation against fast neutrons and γ-rays in the energy ranges of 0.80–11 and 0.40–8.30 MeV, respectively, employing a Pu-Be source and a stilbene scintillator. Theoretical calculations were prepared using the NXcom program to validate the fast neutron attenuation measurements. Furthermore, the implications of the physical, mineralogical, geochemical, and morphological characteristics of these heavy-weight minerals with respect to their attenuation efficiencies were considered. We found that barite has superior radiation attenuation efficiency for fast neutrons and γ-rays compared to hematite by 9.17 and 51% for fast neutrons and γ-rays, respectively. This was ascribed to the superior physical, mineralogical, geochemical, and morphological properties of the former relative to those of the latter. Furthermore, a satisfactory agreement between the experimental and theoretical results was achieved, with a deviation of 16 and 19.25% for the barite and hematite samples, respectively. Eventually, barite and hematite can be successful candidates for their use as sustainable alternatives to common RSC.

Scrutinizing the physical, structural, elastic, optical and gamma ray shielding properties of Samarium ions infused Niobium Bariumtelluroborate glasses

The present work reports the physical, structural, elastic, optical, and radiation shielding studies on (80˗X)H3BO3+10TeO2+9.5Nb2O5+XBaO+0.5Sm2O3 (where X = 10, 20, 30, 40, 50 in wt%) glasses which is prepared by the melt quenching technique. The bending and stretching vibrations of the different compounds used are analyzed through FTIR instrumentation. The density and refractive indices are measured experimentally following Archimedes's principles and by using Abbe's refractometer, respectively. Various structural parameters are calculated to resolve the actual placement of atoms in the glass complex, which explains the compactness of the network. Elastic properties of the synthesized glasses are calculated to estimate the resistance of glass under stress. Additionally, the optical band gap is calculated, and the nature of bonds in the network is ionic compared to the covalent nature. Boron–Boron distance is the lowest for 50BNTBSm sample. The decrease in OPD content is linked with the decrease in the number of oxygen atoms, for 10BNTBSm and 50BNTBSm glasses, it is 289 and 209 oxygen atoms, respectively. Λth value is high for 10BNTBSm glass sample with the minimum BaO reinforcement. The Urbach's energy varies from 0.534 to 0.967 eV, corresponding to xBNTBSm samples indicating fewer defects in the glasses. Moreover, gamma-ray and fast neutron attenuation properties of xBNTBSm are determined and compared with numerous shielding materials such as concrete and other types of glasses. Results showed that replacing 40% of H3BO3 with BaO leads to a net improvement in gamma-ray attenuation properties. However, this situation was the opposite in the fast neutron absorption properties. A clear superiority of sample 50BNTBSm was also reported against the compared absorbent materials. It can be concluded that replacing 40% of H3BO3 with BaO would provide some significant improvements to Niobium Bariumtelluroborate glasses.