137Cs Source Research Articles

Caesium-Iodide-Assisted Synthesis of High-Quality, Stable, and Robust Lead-Free Perovskite Quantum Dots.

The poor morphology, and susceptibility to oxidation of tin-based perovskite quantum dots (TQDs) have posed significant challenges, limiting their application potential. This study presents a straightforward method for synthesizing high-quality CsSnI3-based perovskite quantum dots (TQDs) by incorporating a mixed Cs source of Cs2CO3 and CsI. The addition of CsI increased the I:Sn ratio while maintaining Sn:Cs, resulting in TQDs with smaller size and improved uniformity. X-ray photoelectron spectroscopy (XPS), and Nuclear magnetic resonance (NMR) analyses confirmed enhanced crystallinity, photoluminescence intensity, and antioxidation ability of CsI-TQDs. Remarkably, these TQDs exhibit exceptional stability, enduring over 1 h in air and more than 24 h before complete oxidation, surpassing the previously reported longest lifetime in air for TQDs with conventional oleic acid (OA) and oleylamine (OAm) ligands. Furthermore, these TQD films retain robustness after ligand exchange with methyl acetate (MeOAc) and formamidinium iodide (FAI), representing the first successful short-ligand exchange of TQDs and enabling further electronic device applications. These findings suggest that CsI in the Cs source plays a crucial role in facilitating the formation of surface complexes, regulating TQD growth and suppressing iodine vacancies.

A Novel Anthropometric Phantom for Rapid Radiological Triage: A Quick Sort Triage Solution.

Rapidly identifying individuals who have received internal radiation exposure above action guidelines is crucial for mitigating health risks and addressing public concerns immediately following a radiological event involving the dispersal of radioactive materials. This study describes a novel triage method using a conventional Geiger-Mueller (GM) detector to select those individuals from the large group of persons who may have received an intake of radioactive material at levels corresponding to one Clinical Decision Guide (CDG). The triage method involves placing a portable GM detector against the lower anterior torso of a sitting person as they bend over to surround the detector with their body. The response of the GM detector is evaluated using a new, specially designed anthropometric phantom that simulates combined tissues of the lower thorax and gastrointestinal (GI) tract and is fabricated with a tissue substitute material that matches the overall radiological properties of human tissue present in this body region. The phantom has four separate layers of tissue substitute material with ports to accommodate a single GM detector at the center and one or more sealed radioactive sources that can be arranged to characterize the detector response for a variety of source distributions, including a "hot spot." In this study, the response of a Ludlum Model 133-4 GM detector was evaluated using sealed sources of 232Th and 137Cs to determine the measurement efficiency for a quantity of activity present in the abdomen within a few hours post-intake equivalent to 1 CDG. Results demonstrate that the Quick Sort triage procedure using a single GM detector placed against the abdomen of a person can reliably detect internal deposition resulting from an intake equivalent to 1 CDG for 232Th or a significantly lower activity of 137Cs within a few hours following a radiological incident. The evaluation was performed over a wide range of photon energies, so the Quick Sort triage procedure is expected to be suitable for most fission products distributed uniformly within the abdomen or as a single "hot spot."

Evaluation of cement density utilizing through-casing X-Ray logging method

In the evaluation of cementing quality, quantitatively assessing cement density is crucial along with identifying the cementation degree at the interface using acoustic logging. While the 137Cs-based formation density logging method is well-suited for density calculation, its reliance on open-hole environmental measurements poses challenges when inspecting cement density. This work focuses on the quantitative calculation of cement density while considering the radioactive hazards to the environment caused by 137Cs source. The proposed approach utilizes a measurement system consisting of an X-Ray source and four gamma detectors. The gamma spectrum characteristics of each detector are analyzed, and the energy spectrum recorded by each detector is distinguished by different energy windows. A forward model is established to relate the gamma counts of each energy window to the formation and cement parameters. By employing a regularized Newton’s method based on optimization technique, cement density can be calculated with a controllable error margin of within 0.015 g/cm3. Furthermore, even though X-Ray detection has lower sensitivity to formation parameters compared to 137Cs, this method is capable of estimating formation density. Overall, the proposed approach enables the quantitative calculation of cement density and semi-quantitative calculation of formation density, therefore is of significance to the comprehensive evaluation of cementing quality.

The efect of low-dose gamma radiation on the development of plants from irradiated Pisum sativum sprouts in laboratory experiments

The problem of radiation exposure to organisms is relevant for areas where nuclear industry enterprises are located. Plant biotests are widely used for biotesting of anthropogenic factors affecting the environment, including radiation. The sensitivity of growth and cytogenetic parameters of the biotest based on Pisum sativum to the action of gamma irradiation n has been shown before, but only at high doses. The purpose of this work was to evaluate the influence of low-dose gamma irradiation on the development of Pisum sativum over 6-10 days after irradiating the sprouts. In the experiments, seeds of the Radomir sowing variety from the collection of the pea breeding laboratory of Krasnoyarsk Research Institute of Agriculture - Federal Research Centre Krasnoyarsk Scientific Center SB RAS were used. Pea sprouts were irradiated with a 137Cs source for 24 and 72 hours, with the absorbed dose being 20 and 62 mGy. After irradiation, the sprouts were grown in a climatic chamber on hydroponics for 10 days (240 hours). The control consisted of non-irradiated sprouts grown under identical conditions. The experiments for the first time provided reliable data on the negative effects of gamma irradiation (20 and 62 mGy) on the development of sowing peas 6-10 days after irradiation. A negative effect of gamma irradiation on the growth of the main and lateral roots of young plants was revealed. The experiments with irradiated pea sprouts confirmed the previously known fact that plant roots are more sensitive to irradiation compared to shoots. The pattern of change in the length of the main root of peas over time during germination at a dose of 20 mGy is described by a linear equation, while for a higher dose of irradiation, 62 mGy, the data can be approximated by a logarithmic equation with saturation. The different character of root length dependence on the time of cultivation after irradiation indicates a possible trend in plant growth under various doses of irradiation and cultivation times.

Testing and results of an open-source radiation epidemiology model using the Goiânia accident

In the event of dispersed radioactive materials, whether from accidental orphan sources or deliberate use of radiological dispersal devices (RDD) or radiological exposure devices (RED), free open-source modelling codes can greatly assist in forecasting the dispersion of the radiation following the event. Several codes are currently available to quickly calculate the progression of radiological dispersion. However, most of these codes can only simulate the evolution of the threat for limited times after the event and over relatively short distances from the location. In order to predict the transport of radioactive material over long distances and for long times, and thus prevent its expected effects on the exposed population, specific epidemiological codes can be used, taking into account the characteristic of the radiation. If it is considered that radioactive material can be deposited on unsuspecting people who continue their daily activities after exposure, it can be assumed that these people unintentionally carry this radioactive material over long distances. This scenario is comparable to viral vectors of a hypothetical virus designed to mimic the physical characteristics of radiation. In this work, the free open-source spatio-temporal epidemiological modeller (STEM) tool is used to simulate the spread of a chimeric viral agent with specific characteristics of Ebola and COVID-19, designed to replicate the biological conditions caused by exposure to a Cs-137 source for an individual unaware of the risk. The goal is to predict the territorial spread of radioactive material caused by a CBRNe event, such as orphan sources or the use of a RDD or a RED, and its possible effects on the affected population. This supports decision-makers in forecasting the consequences of radioactive material spread and thus helps in reducing the risk. The code was tested comparing its results with the real case of the famous 1987 Goiânia radiological accident. The results show that the developed code was indeed able to accurately represent the number of contaminated individuals and the number of casualties within a month of the initial exposure, with a distribution of radioactive material in the territory similar to that actually caused by the Goiânia accident.

Experimental evaluation of the impact of ZnO on the radiation shielding ability of B2O3–PbO–ZnO–CaO glass systems

In this study, we used the melt quenching process to develop inexpensive, new radiation shielding glasses. The prepared glasses have a general formula 40B2O3–20PbO-(y)ZnO-(40-y)CaO, (y = 20, 25, 30 and 35 mol%). These glasses' gamma-radiation shielding properties were experimentally measured using Am-241, Co-60, and Cs-137 sources and a High-Purity Germanium (HPGe) detector, revealing that incorporation of ZnO had a positive impact of the density of these glasses. Moreover, the incorporation of ZnO enhanced the prepared glasses' attenuation performance. With greater energy the half value layer increased, and by a factor of 45 with a 0.059–1.333 MeV energy increase. For the four studied glasses the radiation protection efficiency (RPE) values are 100 % efficient at low energies (0.059 MeV), with a drastic decrease in the values across all four samples as the energy increases from 0.06 to 0.662 MeV.

Влияние малых доз ионизирующего излучения при облучении in vitro на показатели крови

Abstract. The purpose is the determination of the degree of influence of small absorbed doses of ionizing radiation on biochemical and hematological parameters during irradiation of peripheral blood samples of cattle in vitro. For the work, blood samples were taken from lactating cows kept under the influence of the background absorbed dose in the Krasnoyarsk Territory, followed by in vitro irradiation at doses of 5, 50, 500 mGy. Methods. Peripheral blood was taken from blood vessels from the tail vein into vacuum tubes with a coagulation activator, in vitro irradiation of samples was carried out on an installation equipped with a Cs-137 source, biochemical studies of blood serum were carried out using a PE-5400UF spectrophotometer. Hematological blood parameters were determined according to generally accepted methods. Results. Ionizing radiation in vitro in doses of 5 mGy, 50 mGy and 500 mGy of peripheral blood samples of cattle affects hematological parameters in different directions, which is characterized by wave-like fluctuations in hemoglobin values, a decrease in the content of erythrocytes and a decrease in the erythrocyte sedimentation rate. It was found that a single irradiation of peripheral blood samples of cows at a dose of 5 mGy reduced the concentration of beta-globulins and creatinine and did not affect the content of total protein and protein fractions. When exposed to ionizing radiation at a dose of 50 mGy, the content of total protein, the level of beta-globulins, creatinine decreased in blood samples, and the content of albumins and alpha-, gamma-globulins did not change. When irradiated at a dose of 500 mGy, the relative content of alpha-globulins, the concentration of ALT and AST decreased, the content of creatinine, total protein, albumins and beta-, gamma-globulins did not change. The stability of alkaline phosphatase, albumins and gamma globulins to ionizing effects at doses of 5 mGy, 50 mGy and 500 mGy has been established. Scientific novelty. The linear dependence of the concentration of alpha-globulins, AST and ALT on the absorbed dose was revealed, the numerical values of the approximation coefficients describing the decrease in concentration and biochemical parameters were determined. The inverse direct linear relationship between creatinine stability and absorbed dose has been established. Practical significance is the established digital values of the approximation coefficients of alpha globulins, AST and ALT can be used in the reconstruction of radiation dose values in the range of 5–50 mGy.

Study on Characteristics of Epoxy Resin-Based Plastic Scintillators for Detectors with Simulation Using Monte Carlo Code

Abstract To determine the presence of radioactive materials emitting gamma rays entering or exiting nuclear facilities, ports, airports, international borders, or other strategic locations, radiation portal monitors (RPMs) capable of detecting such gamma radiation need to be installed in these places. National Research and Innovation Agency of Indonesia (BRIN) is currently developing RPMs with detector components made of plastic scintillator based on epoxy resin and augmented with aromatic fluorescent materials to produce visible light, which is the working range of the photomultiplier tube (PMT) or silicon photomultiplier (SiPM). This research aims to study the characteristics of the gamma photon radiation energy spectrum from Co-60, Cs-137, and Ir-192 sources in an epoxy resin plastic scintillator and study the absorbed dose of the scintillator to gamma photon radiation energy from Co-60, Cs-137, and Ir-192 sources as a function of source distance and incidence angle of gamma rays with simulations using the MCNPX code. The scintillator is modeled in the form of a cylinder with a diameter of 5 cm and a height of 5 cm. To simulate the gamma photon radiation energy spectrum in the scintillator, the F4 tally was used and to simulate the scintillator absorbed dose, the F6 tally was used. This simulation used gamma sources of Co-60, Cs-137, and Ir-192 of 1 mCi each. These characteristics of the epoxy resin plastic scintillator have been successfully simulated. Data on the characteristics of epoxy resin plastic scintillators is important to know and study as supporting data in making plastic detectors as part of the manufacture and development of RPM.

Selection of the Optimal Concentration of Nitro Blue Tetrazolium Dye in Polyvinyl Alcohol Film for Diagnostic Radiology

Ensuring the limited exposure of both patients and medical professionals to radiation during examinations is paramount. One effective approach is the utilization of a film dosimeter that is not only efficient but also easy to carry. In this research, we employed polyvinyl alcohol/nitro blue tetrazolium (PVA/NBT) with varying concentrations of NBT dye (ranging from 0.015 to 0.3 g) to identify the most optimal concentration. These films were subjected to low doses of gamma rays (8, 25, 55 and 96 mGy) emitted from 3 Cs-137 sources. XRF analysis confirmed the effectiveness of the preparation method used, and the NBT salt exhibited excellent solubility (R2 = 0.93). The films exhibited an increasing yellow hue as the concentration of NBT dye rose. Following irradiation, they took on a yellowish-brown tint, intensifying with higher gamma doses. PVA/NBT films, when stored in the dark, demonstrated good stability for 30 days post-irradiation. Analysis using ImageJ software unveiled that the relative density of the red color heightened proportionally with the concentration of NBT dye. XRD patterns showcased the clarity of structural rearrangements occurring after irradiation with high NBT concentrations. Two distinct peaks were registered at 2θ = 20.12 and 40.94 °, which shifted to 2θ = 19.74 and 41.30 ° post-gamma irradiation. The CIELab system study and K/S color strength indicated that increasing the NBT dye concentration led to a linear rise in color strength with escalating low gamma doses. Through a comprehensive assessment, it is concluded that PVA/NBT film can be effectively employed as a dosimeter for low gamma doses in diagnostic radiology. HIGHLIGHTS Nine different concentrations of NBT dye were used to prepare PVA/NBT films. The standard dose scale in diagnostic radiology (mGy) was applied in this work. CIELab system parameters showed a linear increase with increasing applied dose. XRD pattern recorded a shifted peak after irradiation from 2θ = 20.12 to 19.74 °. The dose-response was affected by increasing the NBT dye to a certain concentration. GRAPHICAL ABSTRACT

New readout system of the FATIMA detectors based on Silicon Photomultipliers arrays

We present a new readout system based on large area Silicon Photomultipliers arrays coupled with cylindrical 1.5 × 2” LaBr3(Ce) FATIMA-type crystals. This achieves the fast-timing capabilities of such crystals coupled to the usual Photomultiplier Tubes. Energy calibration was measured with 137Cs and 152Eu standard radioactive sources, while the timing performances were investigated with a 60Co radioactive source. We benchmark our results against the corresponding results obtained with the fast R9779 Photomultiplier tubes and highlight the importance of achieving similar energy and timing performances for nuclear structure experiments. The FWHM energy resolution for the 1.5 × 2” LaBr3(Ce) crystal coupled with the SiPM and PMT was found to be 3.31(2)% and 3.85(1)%, respectively, for the 661.6 keV transition of the 137Cs source. The timing resolution was measured between a conical crystal known for its fast response and a cylindrical crystal coupled to a SiPM or PMT readout. We obtain values of FWHM = 230(1) ps and 232(1) ps, respectively, between the 1173.2-1332.5 keV transitions of the 60Co source. In addition, a temperature effect compensation circuit was developed to maintain a good stability of the gain during long measurements, typical for in-beam/off-beam experiments in nuclear physics.

Simulation of gamma reference field at Institute for Nuclear Science and Technology using Monte Carlo method

This paper presents the characterization of two gamma reference fields of 137Cs and 60Co sources at the Institute for Nuclear Science and Technology. The characterization of the fields in terms of gamma fluence Φ, mean energy, EΦ, kerma weighted mean energies, Eₖ, air kerma, Eair, were determined at various distances from the source center by Monte Carlo simulation using MCNP6. The air kerma results were compared with the measurements obtained by using a calibrated ionization chamber. The discrepancy between the simulated and measured air kerma was less than 4.5%. The scatterred component was also simulated and calculated. The results of both methods showed that the contribution of the scattered components to the gamma reference field is less than 3%. This contribution comply with the international standard criteria of ISO 4037 (<5%). The results confirmed that the characterization of the gamma reference field could be determined using the simulation code.

The Evaluation of Machine Learning Techniques for Isotope Identification Contextualized by Training and Testing Spectral Similarity

Precise gamma-ray spectral analysis is crucial in high-stakes applications, such as nuclear security. Research efforts toward implementing machine learning (ML) approaches for accurate analysis are limited by the resemblance of the training data to the testing scenarios. The underlying spectral shape of synthetic data may not perfectly reflect measured configurations, and measurement campaigns may be limited by resource constraints. Consequently, ML algorithms for isotope identification must maintain accurate classification performance under domain shifts between the training and testing data. To this end, four different classifiers (Ridge, Random Forest, Extreme Gradient Boosting, and Multilayer Perceptron) were trained on the same dataset and evaluated on twelve other datasets with varying standoff distances, shielding, and background configurations. A tailored statistical approach was introduced to quantify the similarity between the training and testing configurations, which was then related to the predictive performance. Wilcoxon signed-rank tests revealed that the OVR-wrapped XGB significantly outperformed the other algorithms, with confidence levels of 99.0% or above for the 133Ba, 60Co, 137Cs, and 152Eu sources. The findings from this work are significant as they outline techniques to promote the development of robust ML-based approaches for isotope identification.

Mechanical and thermal stability properties improvement of polyethylene wax-coated tungsten carbide/high-density polyethylene γ-rays shielding composites through irradiation-induced crosslinking

It is well known that the properties of polyethylene can be improved by irradiation-induced crosslinking the formation of three-dimensional network structures. This paper investigated the effects of gamma irradiation on the mechanical, thermal stability, and γ-rays shielding properties of TAIC-containing γ-rays shielding composites (HDPE/WC-PEW/TAIC). As a result, SEM images showed that agglomerations are alleviated after polyethylene wax (PEW) coated tungsten carbide (WC). The tensile strength and hardness increased from 25.39 MPa to 94 HA to 29.49 MPa and 98 HA after 50 kGy irradiation in vacuum as compared with all composites, while the thermal stability was also improved. The XPS and gel content results showed that the more crosslinked structures generated after 50 kGy irradiated in vacuum between high-density polyethylene (HDPE) and PEW, but irradiation in air is accompanied by the destruction of polymer skeleton. Moreover, the shielding rates of HDPE/WC-PEW/TAIC with thickness of 2 mm and containing 50 wt% WC can exceed 50% and 25% for 137Cs and 60Co sources respectively. In summary, HDPE/WC-PEW/TAIC could be an alternative to lead as γ-rays shielding material with excellent mechanical, thermal, and γ-rays shielding properties after 50 kGy irradiation in vacuum.

Determination of electron‐hole pair creation energy in Cd0.9Zn0.1Te0.98Se0.02 quaternary semiconductor for room‐temperature gamma‐ray detection

AbstractWe report the first‐time measurement of the electron‐hole pair (ehp) creation energy (Wehp) in novel Cd0.9Zn0.1Te0.98Se0.02 (CZTS) quaternary semiconductor. CZTS in single crystalline form is poised to be the future of large‐volume room‐temperature gamma‐ray detectors due to its excellent compositional homogeneity with highly reduced defects, high‐Z (atomic number) constituents, wide bandgap (1.6 eV), and superior charge transport properties. Despite a great deal of study of the material and device properties since its inception, the Wehp in CZTS has not been measured experimentally. Accurate determination of Wehp is essential for calibration of the spectrometer and other theoretical calculations. In this study we have used an absolute calibration approach, which is based on an iterative approach that yields the Wehp as the best‐fit parameter. Using a 241Am alpha emitting radioisotope and a planar CZTS detector, the Wehp in CZTS was calculated to be 4.47 eV. The obtained value has been validated by accurately predicting the peak energy for gamma rays emitted by a 137Cs source and read by a CZTS detector with different dimensions. The dependences of the calculated Wehp value on the detector dimensions, type of interaction, and effect of charge trapping are also discussed.

Investigation of the gamma ray shielding properties of Epoxy based on Bi2O3/GO nanocomposite

Abstract One of the important carbon materials, graphene oxide (GO), has several oxygen-containing functional groups. Due to its unique structure, it has attracted increasing interest in multidisciplinary studies of physical and chemical attributes. In this work, Bismuth Oxide nanoparticles (Bi2O3) is prepared and functionalized with graphene oxide nanosheets (Bi2O3-GO). The Bi2O3 and Bi2O3-GO nanocomposite were mixed with epoxy by changing the percentages to 1%, 2.5%, 5%, and 10%. The study used a hyper-pure germanium detector to investigate the attenuation characteristics of the prepared samples. Ba133, Cs137, and Co60 point sources were used at photon energies of 81, 276, 302, 356, and 383 keV for Ba133, 661 keV for Cs137, and 1173 and 1332 keV for Co60. The linear attenuation coefficient, mass attenuation coefficient, half-value layer, and tenth-value layer were estimated to investigate the radiation shielding characteristics of the prepared samples. The linear attenuation coefficient (μ) values varied from 0.45 to 0.88, 0.23 to 0.89, and 0.31 to 0.77 for Ba133, Cs137, and Co60, respectively. The mass attenuation coefficient (μm) values varied from 0.18 to 0.50, 0.19 to 0.50, and 0.15 to 0.50 for Ba133, Cs137, and Co60, respectively. Half-value layer (HVL) values varied from 0.79 to 1.55, 0.78 to 3.07, and 0.9 to 2.26 for Ba133, Cs137, and Co60, respectively. Tenth-value layer (TVL) values varied from 2.61 to 5.16, 2.58 to 10.19, and 2.98 to 7.51 for Ba133, Cs137, and Co60, respectively.

Gamma ray shielding ability of Y3+ doped borophosphate glasses

Abstract Four selected Y2O3 doped borophosphate glass samples are prepared using melt quench technique. The structural properties such as density and molar volume are measured. The density (ρ) increases from 3.1384 to 3.4613 g/cm3 whereas molar volume (Vm) decreases from 60.84 to 55.00 cm3 mol−1 with addition of Y2O3 cm3 mol−1 content. The lattice of the glasses has been tested via X-ray diffraction which is a good technique for confirming the structural properties of these glasses and FTIR spectra. In addition, radiation shielding parameters for glasses were performed theoretically utilizing XCOM program for various gamma ray energy and experimentally using NaI(Ti) scintillation detector, The glasses were irradiated using energies 0.664, 1.174 and 1.334 MeV emitted by Cs-137 and Co-60 radioactive point sources respectively. Shielding parameters as leaner (μ), mass attenuation coefficients (μ/ρ) and half value layer (HVL), tenth value layer (TVL) and mean free path (MFP). The concentration of Y2O3 increases the (μ/ρ) increases, the HVL, TVL, and MFP values have inverse way. Superior radiation shielding is confirmed by the glass sample containing (3%, mole) of yttrium oxide. The results show that the borophosphate glasses doped with Y2O3 can be used to shield gamma rays.

A comparative analysis of the NaI detector response function using GAMOS and FLUKA Monte Carlo simulations

This work aims to study the response function of a 2″×2″ NaI(Tl) scintillation detector using Monte Carlo simulations. A precise mathematical model of the NaI(Tl) scintillator was developed using both FLUKA and GAMOS Monte Carlo simulation software. The photon pulse height distributions of the NaI(Tl) without influence of its energy resolution, obtained with FLUKA and GAMOS codes, were converted into a real NaI(Tl) response function using the necessary conversion process. Spectral characteristics such as full-energy peak efficiency, energy resolution, peak-to-Compton ratio, and peak-to-total ratio were investigated by simulation at different gamma-ray energy obtained from 109Cd, 137Cs, 54Mn, 65Zn, and 60Co sources. The simulated spectra from the GAMOS code were consistent with those generated by the FLUKA code. Additionally, the comparison between simulated results and experimental data demonstrated good agreement. The validation of the computational models used for the NaI(Tl) detector in both FLUKA and GAMOS software was successfully achieved, confirming the accuracy of the simulations in replicating the detector's response.

Large-size CsI:Na single crystals for future high energy physics experiment

With the development of deep space exploration, nuclear medical imaging, high-energy physics experiments, and other fields, the demand for large-size CsI:Na crystals is increasing due to the low cost of use, high light yield, and excellent irradiation resistance of CsI:Na crystals. In this work, we investigated the scintillation characteristics of thirty-five Ø76 mm × 76 mm CsI:Na single crystals, delving into the variation of energy resolution and light yield. Meanwhile, a method based on 137Cs source collimation and coupling the crystal to PMT in different directions was used to reveal the uniformity of scintillation performance of large-size CsI:Na single crystals. The Bridgman-grown 51 mm × 51 mm × 152 mm CsI:Na single crystals have an energy resolution of 6.5 % at 662 keV, which does not change significantly regardless of irradiation location or irradiation method.

The effect of rare earths (Nd3+, Er3+, Yb3+) additives on the radiation shielding properties of the tungsten oxide modified tellurite glasses

Abstract In this study, we have reported on the effect of the rare earth oxides on the radiation protection performance of the tellurite glasses. In order to determine the effect of rare earth oxides on the radiation shielding properties of tungsten oxide (WO3) modified tellurite glasses, three rare earth element oxides (Nd2O3, Yb2O3, and Er2O3) have been selected. The glass systems have been synthesized using the traditional melt quenching method and were doped with the different amount (1 %, 3 %, 5 %) of the oxides of rare earth elements (Nd2O3, Yb2O3, Er2O3). The linear attenuation coefficient, mass attenuation coefficient, half value layer, and effective atomic number of the synthesized samples were experimentally measured for 662, 1,173 and 1,332 keV gamma-ray energies which were emitted from 137Cs and 60Co radioactive sources. Measurements were conducted in narrow beam transmission geometry using a NaI(Tl) scintillation detector. In addition, all these parameters were calculated theoretically using the WinXCOM program in the energy region of 0.015–15 MeV. The addition of different types and amounts of rare earth oxides to the tellurite glass system was found to significantly enhance the radiation protection performance of the glasses. In particular, it was found that the radiation shielding characteristics of the glasses improved with increasing amount of rare earth doping, the TWYb5 glass system had the best radiation shielding properties, and there was a trend among the doped rare earth oxides in the form of Yb > Er > Nd according to their radiation shielding performance.

High quantum yield luminescence and scintillation properties of high-Ce-doped MgF2–Al2O3–B2O3 glasses and their glass structure

Ce-doped inorganic single crystals are currently used in scintillators in various instruments because of their outstanding luminescence properties. However, these crystals are expensive to manufacture and are inefficient in terms of their energy consumption. In this study, xCeF3-doped 40MgF2–20Al2O3–40B2O3 glasses (x = 0−30 mol%) were prepared by a melt-quenching method in N2 atmosphere, and their photoluminescence, scintillation, and dosimetry properties were investigated. The X-ray absorption fine edge spectroscopy of the Ce L3-edge indicated that the doped Ce exists in the form of Ce3+ ions, and that Ce4+ does not form because of the low basicity of the glass. The glasses underwent photoluminescence at 380 nm due to the 5d-4f transition of Ce3+, with a very high quantum yield of up to ∼100 % and low concentration quenching. The peak shape of the X-ray-induced luminescence was similar to that of the PL with a decay time of 110−70 ns. The light yields for gamma rays (137Cs source) were obtained from the pulse-height spectra, and the highest light yield among the present samples was 1071 photons/MeV with the energy resolution of 17 %. The thermoluminescence glow curves had peaks at 365 and 460 K and a good linear relationship existed in the range of 0.5–1000 mGy, with the dose response being comparable to that of a commercial dosimeter. The origin of the high quantum yield was probed by analyzing the glass structure using molecular dynamics simulation based on a graph neural network. A strong tendency to selectively bind cations and anion pairs was found: Mg preferably binds to F, B preferably binds to O, and Al binds to O and F, which can be explained by soft and hard acid and base theories. Because of this selectivity the glass forms fluoride- and oxide-rich domains, which seem to be responsible for the more effective dispersal of the luminescent center. The results of this study are expected to contribute to the development of glasses with enhanced photoluminescence and scintillation luminescence properties.