Atomic Energy Research Articles

Thermoluminescence characterization of flooring tiles from Malaysia for potential use in retrospective dosimetry

In the event of natural disasters or technical malfunctions at nuclear sites, the surrounding media, including individuals, may be subject to unforeseen radiation exposure. Thus, it is not possible to determine the precise level of radiation exposure that each person has received in this scenario. To handle such a problem, the use of retrospective dosimetry can offer an accurate evaluation of the radiation dose acquired as a result of such incidents. This information enables the development of suitable remedial actions. Normally, in the region that has been impacted, several artifacts can serve as natural dosimeters. The study involved the utilization of locally available seven different brands of flooring tiles in Malaysia for the possibility of being used in retrospective dosimetry through exposures to 60Co gamma-rays within a range of 10–200 Gy. To understand the luminescence features of this material, a convenient thermoluminescence (TL) technique has been employed. The dosimetric features of the samples were investigated, including their effective atomic numbers (Zeff), reproducibility, glow curve, dose response, sensitivity, linearity index, energy dependency and fading, which is representative of the usual TL method. Additionally, by analyzing the glow curves of the irradiated samples together with the peak shape method and the initial rise methods, several kinetic parameters, including the kinetic orders (b), activation energy (E) or trap depth, frequency factor (s) or escape probability, and trap lifetime (τ) were calculated. Different kinds of tiles exhibit distinct scenarios in terms of kinetic characteristics. T1 sample exhibits the highest degree of sensitivity and a highly linear dose response among the tile samples that were evaluated. Also, T1, T3, and T5 samples show minimal loss of TL intensity (∼38–39%) one year after irradiation, making them ideal for use as a retrospective dosimeter.

Book review: “Guidelines on professional ethics for medical physicists”, Training Course Series 78, Vienna, 2023

Abstract The International Atomic Energy Agency (IAEA) has published the document namely “Guidelines on professional ethics for medical physicists” in 2023. This document complements several other IAEA publications on similar topics like IAEA Human Health Series 25. The “code of ethics” in medical physics practices is an essentially important topic and this publication covers the topic comprehensively. However, a few areas of improvement like the correlation of this publication with the concepts of leadership, safety culture, etc. have been identified in this review.

‘Welcome to Dounreay’: Ideological narratives of hospitality at the Dounreay visitor centre, c.1960–2007

Dounreay Nuclear Power Development Establishment (NPDE) was built in the far north-east of Scotland due to the possible ‘misbehaviour’ of the technology and the dangerous nature of the materials involved. From 1960 to the eve of decommissioning in 2007, despite numerous health and safety issues across the Dounreay nuclear facility, a visitor centre operated there. Initially, its purpose was to satisfy public curiosity and provide information about the atomic work being undertaken. From the 1970s, however, the objective of the Dounreay visitor centre shifted, to focus on overcoming public objections to nuclear power. Archive material made available by the Nuclear Decommissioning Authority (NDA) was analysed according to themes addressed in the literature review. Findings reveal an ideological narrative curated by the UK Atomic Energy Authority (UKAEA) and presented to the public via exhibitions, brochures, hands-on displays and outreach activities. At the visitor centre, Dounreay and its associated technologies were simplified, ‘banalized’, via a narrative that sought to frame an inhospitable destination (Dounreay) as a safe, welcoming and hospitable place to visit.

Compatible multilayer magnetic field system for quantum sensing with atoms.

Magnetic fields provide a valuable method to manipulate atomic energy levels and interactions in quantum precision measurements, but achieving precise measurements requires collaboration between the magnetic field system and the optical detection system. We propose a magnetic field system that incorporates a fast-switching magnetic field and an alternating magnetic field. Specifically, we enhance the switching speed by making structural improvements during the switching operation. An independent control approach is employed to reduce the switching time caused by electromagnetic induction across the coil using multilayer coils. The results demonstrate an inverse correlation between the rise and fall times of the magnetic field switch and the number of independently stacked coil layers, indicating the possibility of achieving further improvements in switching speed through structural enhancements. The system developed here has considerable potential for application to diverse quantum systems.

МЕТОДОЛОГИЯ КЛИНИЧЕСКИХ АУДИТОВ ОТДЕЛЕНИЙ ЛУЧЕВОЙ ТЕРАПИИ В РФ НА ОСНОВЕ ПРИНЦИПОВ АУДИТА МАГАТЭ QUATRO

Purpose: To describe the essence, tasks and algorithm of comprehensive audit in radiotherapy departments of medical institutions in Rus sian Federation. The methodology of audits conducted by the International Atomic Energy Agency (IAEA) and adapted for its further application, was used as a model. The global goal of the audit project is to standardize and harmonize procedures to ensure safety and quality control of treatment of cancer patients in different institutions, to enable comparison of radiation therapy results among participating institutions, to conduct interclinical studies and, possibly, to create a unified data register. Material and methods: One of the main aspects of clinical audits is the harmonization of standards between different departments. Clinical audits in radiotherapy can be an important tool for interclinical quality assurance (QA) program, effectiveness and safety of radiotherapy, and treatment protocols synchronization. Audits allow an in-depth analysis of the procedures and processes governing patient care in a particular clinic. Such clinical audits cover the whole chain of patients care, the organization of structural units, the infrastructure, clinical, physics and technical aspects underlying the radiotherapy department. This audit is a peer review process conducted by an audit team consisting of a radiation oncologist (RO), medical physicist (MP) and radiation technologist (RTT) and is known as QUATRO and stands for Quality Assurance Team in Radiation Oncology). Possible audit tools include: 1. Saff interviewing. 2. Examination of the structure of the entire department. 3. Review and evaluation of procedures and all relevant documentation, including analysis of patient charts. 4. Conducting independent measurements of absorbed doses and other methods of local procedures monitoring, where relevant and appropriate. 5. Observation of the practical implementation of operating procedures. Results: It was decided to use the IAEA QUATRO methodology for clinical audits and to adapt it to the specifics of radiotherapy in Russian Federation. One of the advantages of such a clinical audit is that the formalism and algorithm of this approach will be identically applied in all departments, which will allow comparing and analyzing the results. In order to obtain structured information, a detailed research protocol, which is a questionnaire, has been developed. The questions in the questionnaire allow to assess key aspects of the radiotherapy process that affect clinical outcomes and treatment efficiency.

Electrical properties of different materials studied by sub-microsecond underwater electrical explosions of single wires

Results of an experimental research and one-dimensional hydrodynamical simulations of critically damped sub-microsecond timescale underwater electrical explosions of wires made of 12 different materials are presented. Using current and voltage waveforms, streak shadow images of the shocks generated in water and wire expansion obtained by one-dimensional hydrodynamic simulations, the maximal values of the energy density, energy density deposition rates, and specific action integrals were determined. It is shown that for all study materials, the deposited energy density significantly exceeds the energy density required for the solid–liquid phase transition but is substantially smaller to induce a full liquid–vapor phase transition of the wire. At the time when the maximal value of the deposited power is realized, the deposited energy densities were found to be larger than the atomization energy for all materials. Estimates of the plasma parameters show that the explosion of the wires can be characterized by a high resistance and lowly ionized weakly coupled plasma. Three groups of materials were distinguished by either decrease, plateau, or increase in the resistance after the maximum of the deposited power. It was confirmed that the observed maximum Planckian temperature for all wire material does not exceed 6000 K due to the “bath” effect and that there is a correlation between the wire radial expansion and the strong shock wave velocities.

Calibration and validation measurements of the Extended-range Bonner sphere spectrometer

An Extended-range Bonner sphere spectrometer (EBSS) has been developed to investigate the neutron spectra of the China initiative Accelerator Driven System. This paper presents the design, calibration, and validation measurements of the EBSS system using a standard 241Am-Be neutron source and the cosmic ray neutrons. The EBSS system was simulated using the PHITS code, and the geometric structures were designed using the response functions obtained by simulations. The EBSS system comprises of seven polyethylene-only spheres and seven extended-range spheres encased in lead, copper, or tungsten shells along with a bare 3He proportional counter. To verify the accuracy of the simulated response functions, the EBSS system was calibrated with monoenergetic neutron beams of 565 keV at the China Institute of Atomic Energy in Beijing. The EBSS system was used to measure neutron count rates of the 241Am-Be neutron source and cosmic ray neutrons. Subsequently, the measured neutron count rates were converted into neutron spectra by the unfolding software. Experimental findings demonstrate the precise capability of the EBSS system to measure neutron spectra across a wide range of neutron radiation fields.

Preface

The 5th International Conference of Geography and Disaster Management 2023 (ICGDM 2023) was successfully held by the Faculty of Geography, Universitas Muhammadiyah Surakarta. The conference was held via online Zoom meeting on 5-6th December 2023. ICGDM 2023 had a relevant theme for the tropical regions which is “Exploring Sustainable Solutions for Regional Development in Tropical Geographies: Unveiling the Potential, Embracing the Challenges”. It aimed to be a scientific platform for research dissemination, ideas sharing, and collaboration related to topics of environmental studies, socio-economic, regional development, disaster management, remote sensing, and GIS applications. ICGDM 2023 invited speakers from different backgrounds who are experts in the field of either physical or socio-economic geography. The keynote speakers were Dr. Nawaz M Mian (National University of Singapore, Singapore), Prof. Christopher Gomez (Kobe University, Japan), Muhammad Aufaristama, Ph.D. (University of Twente, Netherlands), Asaba Joyfred, M.A. (Kyambogo University, Uganda), Dr. Mukhamad Ngainul Malawani, M.Sc. (Universitas Gadjah Mada, Indonesia), Dr. Edy Trihatmoko (Impact Team 2050 Member, State Atomic Energy Corporation Rosatom (ROSATOM), Russia). This ICGDM 2023 was attended by 123 participants and presenters. The committee has received 123 paper submissions, and after the review process, 60 papers were selected for publication in the IOP Conference Series: Earth and Environmental Science. We would like to thank all the authors who have actively participated in the conference. We also highly appreciate the full support from Universitas Muhammadiyah Surakarta. List of Committee is available in this pdf.

Direct prediction of isotopic properties from molecular dynamics trajectories: Application to sulfide, sulfate and sulfur radical ions in hydrothermal fluids

In hydrothermal fluids, disulfur (S2•−) and trisulfur (S3•−) radical anions have been observed to coexist with the major hydrogen sulfide and sulfate species. These radical ions have potentially important effects on the solubility, transport and fractionation of metals and sulfur, with consequences for ore deposit formation and, more generally, for geochemical cycles of metals and volatiles. It is therefore essential to know the intrinsic isotopic properties of these important sulfur species in order to use sulfur isotopes for tracing different geological processes. Here, the theoretical equilibrium isotopic properties of the disulfur and trisulfur radical ions are computed and compared to the hydrogen sulfide (H2S) and sulfate ion (SO42−), using, for the first time, a first-principles molecular dynamics (MD) approach. The isotopic properties are calculated directly from molecular dynamics trajectories using the vibrational density of states and the atomic kinetic energy, and then compared to the more established method based on sampling of several snapshots. This comparison allowed us to validate the new modelling method and to assess its advantages and limitations. The predicted equilibrium isotope fractionation in terms of 34S/32S between S2•− and S3•− is small, i.e. <1‰, with a slight enrichment in the heavier isotope for S3•−, over the temperature range 200–500 °C. Both radical ions are slightly depleted in the heavier isotope, by 1 to 2‰, relative to aqueous H2S. Our results help tuning sulfur isotope fractionation models used for tracing the origin and evolution of hydrothermal fluids. Our method opens large perspectives for using the rapidly growing body of MD simulation data in geosciences on structure and stability of aqueous complexes to assess in parallel element isotope fractionations from MD-generated trajectories.

Molecular dynamics simulations of interaction of cascade damage with self-interstitial atom-loaded grain boundaries in tungsten

In this study, we conducted systematic molecular dynamics simulations to investigate the radiation resistance of grain boundaries (GBs) in tungsten with/without self-interstitial atoms (SIAs) loaded on them. The simulation results show that the presence of SIAs can extend the width of the Σ3<110>{112} twin GB compared to the SIA-free GB. When cascade damage occurs near Σ3, the presence of SIAs at Σ3 enhances radiation resistance. Specifically, it inhibits producing residual defects, particularly vacancies and prevents their aggregating into clusters. The radiation-resistant performance is most excellent when the SIA concentration at Σ3 is approximately 5 %. The influence of temperature and primary knock-on atom energy on radiation damage is also discussed. However, SIA-loaded high angle GBs and low angle GBs do not significantly enhance their radiation-resistant performance compared to their SIA-free counterparts. This study provides valuable insights into the radiation damage behaviors near GBs and contributes to understanding their radiation-resistant mechanisms.

Determination of Diagnostic Reference Level in Dose-Area Product (DAP) and Evaluation of Dosimetry in Chest x-ray Examination at Bingerville Mother-Child Hospital, Cote D’Ivoire

X-rays have an undeniable advantage in medicine, especially for diagnosis. However, their use is not without risk. Following numerous studies carried out by the International Atomic Energy Agency and learned societies, it has been recommended to strengthen the principle of optimization in diagnostic radiology by implementing Diagnostic Reference Levels. The purpose of this study is to determine diagnostic reference levels (DRLs) in order to evaluate radiological practices and to reduce doses received by patients for frontal chest examination at the Bingerville Mother-Child Hospital (MCH). The work was carried out on a sample of 110 patients at the Mother and Child Hospital in Bingerville. We used a generator and a tube for the production of X-rays. The dose-area product (DAP) value was obtained using a dose calculator built into the generator. The determination of the DRLs in DAP (cGy.cm²) was made with the 75th percentile statistical method and yielded the following result of 14.32 cGy.cm². Comparing our DRL value with those obtained elsewhere, as well as comparing the median DAP from the present study with the DRLs in Abidjan and at the national level, radiological practices are satisfactory for frontal chest examination. However, after analysis of some radiological parameters used, it appears that efforts need to be made by acting on the kV, mAs, diaphragm and the filtration.

Evaluation and health risk assessment of arsenic and potentially toxic elements pollution in groundwater of Majha Belt, Punjab, India.

Concentrations of potentially toxic elements (PTEs) like arsenic, uranium, iron, and nitrate in the groundwater of the Majha Belt (including Tarn Taran, Amritsar, Gurdaspur, and Pathankot districts) in Punjab, India were measured to evaluate the health risks associated with its consumption and daily use. The average concentrations of these elements in some locations exceeded the WHO-recommended values. Arsenic and iron toxicity levels were found to be higher in the Amritsar district, while uranium toxicity was more prevalent in Tarn Taran. The Trace Element Evaluation Index suggests that Amritsar is one of the districts most affected by toxic elements. According to the US Environmental Protection Agency's (USEPA) guidelines, the HQ values of U, Fe, and nitrate were less than one, indicating that there is no non-carcinogenic health risk for adults and children. However, the hazard quotient (HQ) value for arsenic was greater than one, indicating a higher possibility of health risk due to arsenic in the study area. The total hazard index values of 44.10% of samples were greater than four for arsenic, indicating that people in the Majha Belt are at a very high health risk due to the usage of water for drinking and domestic purposes. The cancer risk assessment values for arsenic in children (5.69E + 0) and adults (4.07E + 0) were higher than the accepted limit of USEPA (10-4 to 10-6) in the Majha Belt. The average radiological cancer risk values of U for children and adults were 8.68E-07 and 9.45E-06, respectively, which are well below the permissible limit of 1.67 × 10-4 suggested by the Atomic Energy Regulatory Board of DAE, India. The results of this study confirm that the residents of the Majha Belt who use contaminated groundwater are at a serious risk of exposure to arsenic in the Amritsar district and uranium in Tarn Taran district.

Transferability of Buckingham Parameters for Short-Range Repulsion between Topological Atoms.

The repulsive part of the Buckingham potential, with parameters A and B, can be used to model deformation energies and steric energies. Both are calculated using the interacting quantum atom energy decomposition scheme where the latter is obtained from the former by a charge-transfer-based energy correction. These energies relate to short-range interactions, specifically the deformation of electron density and steric hindrance, respectively, when topological atoms approach each other. In this work, we calculate and fit the energies of carbonyl carbon, carbonyl oxygen, and, where possible, amine nitrogen atoms to the repulsive part of the Buckingham potential for 26 molecules. We find that while the steric energies of all atom pairs studied display exponential behavior with respect to distance, some deformation energy data do not. The obtained parameters are shown to be transferable by calculating root-mean-square errors of fitted potentials with respect to energy data of the same atom in, as far as possible, all other molecules from our data set. We observed that 36% and 10% of these errors were smaller than 4 kJ mol-1 for steric and deformation energy, respectively. Thus, we find that steric energy parameters are more transferable than deformation energy parameters. Finally, we speculate about the physical meaning of the A and B parameters and the implications of the strong exponential and exponential-linear piecewise relationships that we observe between them.

Design of the offline test electronics for the nozzle system of proton therapy.

A set of nozzle equipment for proton therapy is currently under development at China Institute of Atomic Energy (CIAE). To facilitate the off-line commissioning of the whole equipment, a set of ionization chamber signal generation system, known as the test electronics, was designed. The results showed that the system can simulate the beam position, beam fluence (which exhibits a positive correlation with the dose), and other related analog signals generated by the proton beam when it traverses the ionization chamber. Moreover, the accuracy of the simulated beam position is within ± 0.33mm, and the accuracy of the simulated beam fluence signal is within ± 1%. The test electronics can output analog signals representing environmental parameters. The test electronics meets the design requirements, which can be used for the commissioning of the nozzle system as well as the treatment control system without the presence of the proton beam.

Probabilistic fracture mechanics analyses of a reactor pressure vessel using the irradiation embrittlement evaluation based on the Bayesian nonparametric method

In the structural integrity assessment of an embrittled reactor pressure vessel (RPV) based on probabilistic fracture mechanics (PFM), it is crucial to consider both of the mean value and the uncertainty of the embrittlement prediction. Typically, the embrittlement prediction uncertainty is given by a normal distribution, and its standard deviation is determined from the residuals of the measured and predicted values of all data used to develop the embrittlement prediction method. Therefore, the same uncertainty is assumed regardless of neutron fluence and the available data. To overcome this issue, the Japan Atomic Energy Agency recently developed the embrittlement prediction method based on machine learning and Bayesian statistics, i.e., the Bayesian nonparametric (BNP) method, and introduced it to the PFM analysis code. The BNP method can predict the probability distribution according to data scarcity and provide more reasonable uncertainty because it estimates significant uncertainties where the scatter of actual measured data is large and the number of data is small. In this study, PFM analysis for a Japanese model RPV in a pressurized water reactor is conducted using the PFM analysis of structural components in aging light water reactors, where the embrittlement probability distribution calculated using the BNP method is used. Furthermore, the effects of different embrittlement prediction methods and uncertainties on the failure frequency of RPVs are investigated in the PFM analyses, and the results are presented.

Constructing and Evaluating Machine-Learned Interatomic Potentials for Li-Based Disordered Rocksalts.

Lithium-based disordered rocksalts (LDRs), which are an important class of positive electrode materials that can increase the energy density of current Li-ion batteries, represent a significantly complex chemical and configurational space for conventional density functional theory (DFT)-based high-throughput screening approaches. Notably, atom-centered machine-learned interatomic potentials (MLIPs) are a promising pathway to accurately model the potential energy surface of highly disordered chemical spaces, such as LDRs, where the performance of such MLIPs has not been rigorously explored yet. Here, we represent a comprehensive evaluation of the accuracy, transferability, and ease of training of five atom-centered MLIPs, including the artificial neural network potentials developed by the atomic energy network (AENET), the Gaussian approximation potential (GAP), the spectral neighbor analysis potential (SNAP) and its quadratic extension (qSNAP), and the moment tensor potential (MTP), in modeling a 11-component LDR chemical space. Specifically, we generate a DFT-calculated data set of 10,842 configurations of disordered LiTMO2 and TMO2 compositions, where TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and/or Cu. To provide a point-of-comparison on the performance of atom-centered MLIPs, we also trained the neural equivariant interatomic potential (NequIP) on a subset of our data. Importantly, we find AENET to be the best potential in terms of accuracy and transferability for energy predictions, while MTP is the best for atomic forces. While AENET is the fastest to train among the MLIPs considered at low number of epochs (300), the training time increases significantly as epochs increase (3300), with a corresponding reduction in training errors (∼60%). Note that AENET and GAP tend to overfit in small data sets, with the extent of overfitting reducing with larger data sets. Finally, we observe AENET to provide reasonable predictions of average Li-intercalation voltages in layered, single-TM LiTMO2 frameworks, compared to DFT (∼10% error on average). Our study should pave the way both for discovering novel disordered rocksalt electrodes and for modeling other configurationally complex systems, such as high-entropy ceramics and alloys.

Theoretical Determination of the Electronic Structures and Energy-Level Splitting for Pr3+-Doped Y2SiO5 Crystals.

Trivalent praseodymium (Pr3+)-doped yttrium silicate (Y2SiO5) crystals have been widely used in various phosphors owing to their excellent luminescence characteristics. Although a series of studies have been carried out on its application prospects, the electronic structures and energy-transfer mechanisms of Pr3+-doped Y2SiO5 (Y2SiO5:Pr) remain an exploratory topic. Herein, the crystal structure analysis by the particle swarm optimization structure search method is used to study the structural evolution of Y2SiO5:Pr. Two novel structures with local [PrO7]-11 and [PrO6]-9 [Y2SiO5:Pr (I) and Y2SiO5:Pr (II)] are successfully identified. The impurity Pr3+ ions occupy the Y3+ sites and successfully integrate into the Y2SiO5 host crystal with a Pr3+ concentration of 6.25%. The calculated electronic band structures show that the doping of Pr3+ induces a reduction in band gaps for the host Y2SiO5 crystal. The conduction bands near the Fermi level are completely composed of f states. For the atomic energies of Pr3+ in Y2SiO5, the Stark levels and transitions are properly simulated based on a new set of crystal field parameters (CFPs) at the C1 site symmetry. A satisfactory r.m.s. dev. of 15.57 cm-1 with 9 free ion parameters (plus 27 fixed CFPs as obtained from ab initio calculation) fitted to the 33 observed levels is obtained for the first time. The plentiful energy-level transition lines, from the visible light to the near-infrared region, are deciphered for Pr3+ in Y2SiO5. Blue 3P0 → 3H4 at 465 nm is calculated to be a strong emission line, and it might be an ideal channel for laser actions. These results could not only provide important insights into the rare-earth-doped crystals but also lay the foundation for future research studies of designing the new laser materials.

Fusion and one-neutron stripping process for 6Li + 94Zr system around the Coulomb Barrier* *This research is supported by the National Nature Science Foundation of China (U2167204, 11975040, 1832130, 12375130), the Director's Foundation of Department of Nuclear Physics, China Institute of Atomic Energy 12SZJJ-202305. The Brazilian authors are grateful to the partial support from financial agencies FAPERJ, CNPq, and INTC-FNA

The complete and incomplete fusion cross section as well as one-neutron stripping process of 6Li + 94Zr system were measured at the energies around the Coulomb barrier by online γ-ray method. In addition to a 30% suppression factor when compared with the measured total fusion process, the complete fusion cross section in 6Li + 94Zr system was observed to be significantly lower than those in the nearby 6Li + 90, 96Zr system. The new experimental result implies that the coupling with breakup channel in the 6Li-induced fusion processes can be affected by the inner structure of the target, which is still not clear in any available model calculation. For the one-neutron stripping process, the direct production cross sections for each level in 95Zr were extracted and compared with the coupled reaction channel calculation, offering a unique opportunity to examine the single-particle nature of the produced excited states. Given the fact that an overall overestimation of the production cross section for 954-keV and 1618-keV levels was observed in the comparison, further investigation is highly demanded in order to understand the full reaction mechanism for the one-neutron stripping process induced by 6Li.

Non-Metal Doping as a First-Principles Study for Promoting the Hydrogen Evolution of Two-Dimensional Electride Y2C Electrocatalysts

The two-dimensional electrochemical Y2C’s low work function and strong charge transfer qualities limit its applicability in catalysis due to its poor catalytic activity. In this paper, based on density functional theory calculations, we use two techniques to increase the HER catalytic activity of the Y2C monolayer: substitution doping (XC) and adsorption doping (XT) of non-metal (X = N, P, O, S, and F). The results showed that the absolute values of hydrogen free energies (ΔGH*) of the substitutional dopants of PC, SC and adsorptive dopants of NT, OT, ST, and PT had increased catalytic activity compared with those of the pristine Y2C monolayer (−0.673 eV). It was highlighted that the adsorption doping of PT can further reduce the adsorption free energy of the pristine Y2C monolayer to −0.19 eV, which is close to the optimal zero value, and the binding energy of the hydrogen atoms on the Y2C surface significantly increased from −0.913 to −0.438 eV, which is more favorable for the desorption of hydrogen atoms. These results demonstrate that the doping of non-metals activates the adsorption of hydrogen atoms on monolayer Y2C and provides a feasible method for hydrogen generation.

A Comparative Analysis of Radioactive Material Concentrations in Natural Sources Linked to Mining in Niger using two Measurement Methods

In the present work, we report the results of radioactivity measurements carried out in soils from the COMINAK and SOMAIR mining areas, using normal mode gamma-ray spectroscopy (NMGS) and thermal neutron activation analysis (TNAA). Radio activities were determined for two series radionuclides (U-238 and Th-232) and one non-series radionuclide (K-40) from measured gamma-ray spectra. The activity concentrations of U-238 and Th-232 were respectively determined from the average nuclide concentration [Pb-214 (295.2keV ; 19.20%), Pb-214(351.9keV ; 37.10%), Bi-214 (609.3keV ; 46.90%), Bi-214 (1120.2keV; 15.04%) and Bi-214 (1764.49 keV; 15.90%)] and [Pb-212 (238.6keV; 43.6%), Pb-212 (300.09 keV; 3.18%), and Ac-228 (911.2keV; 25.8%), Ac-228 (968.9keV; 15.8%), Ac-228 (338.32 keV; 11.27%)]. The activity concentrations of K-40 are determined directly by measuring gamma-ray transitions at 1460.8keV (100%) using a high-resolution pure germanium detector with good efficiency from the Egyptian Atomic Energy Authority. We find that the result found in NMGS technique and TNAA technique for COMINAK soil sample for U-238 and Th-232 are 2.32mg/Kg, 2.36mg/Kg and 11.67mg/Kg, 11.72mg/Kg respectively the results are getting closer. In SOMAIR soil sample the result found for U-238 is getting closer 1.35mg/Kg and 1.34mg/Kg respectively for NMGS and TNAA and also for Th-232 the result is close 7.2mg/Kg and 7.87mg/Kg respectively for NMGS and TNAA. The results obtained confirm that one of the samples (COMINAK soil) is more radioactive than the SOMAIR soil samples, and the results are similar for both NMGS and TNAA techniques, with the exception of thorium in the SOMAIR soil sample. This study will help to assess the environmental impact around the mining areas.