Characterization of residual radioactivity in a cyclotron is an important radiation safety issue, especially during maintenance interventions. Stainless steel and zinc-iron foils were used in this work as neutron activat...Characterization of residual radioactivity in a cyclotron is an important radiation safety issue, especially during maintenance interventions. Stainless steel and zinc-iron foils were used in this work as neutron activation foils to indicate the accumulation of residual radioactivity in the metallic parts of the cyclotron and to monitor the secondary neutron fluence. The foils were positioned near the 201Tl and 67Ga production target system. The main activation products in the foils were 51Cr, 60Co, 54Mn, and 59Fe. The variation of the generated radionuclides in the foils versus the monitoring time was obtained. Moreover, the fast neutron fluence was monitored by measuring 54Mn radioactivity in the foils. Thus, the stainless steel and zinc-iron foils have been successfully used to indicate the residual radioactivity and the neutron fluence. Highlights Characterization of residual radioactivity in a cyclotron is an important radiation safety issue;Stainless steel and zinc- iron foils were used as neutron activation foils to indicate the residual radioactivity in metallic parts of the cyclotron and to monitor the neutron fluence;The main activation products in the foils were 51Cr, 60Co, 54Mn, and 59Fe;The fast neutron fluence was monitored by 54Mn radioactivity in the foils.
New conversion coefficients relating 24Na specific activity in the human body induced by neutron exposure to the corresponding effective dose are presented to estimate public exposure in criticality accidents. The coeffi...New conversion coefficients relating 24Na specific activity in the human body induced by neutron exposure to the corresponding effective dose are presented to estimate public exposure in criticality accidents. The coefficients were calculated using state-of-the-art mesh-type phantoms developed by the International Commission on Radiological Protection (ICRP) and the Particle and Heavy Ion Transport code System code. Calculations were performed for all irradiation geometries defined by the ICRP, with monoenergetic neutrons ranging from thermal energies to 20 MeV. These newly derived coefficients enable a more accurate assessment of neutron radiation exposure to the general public in criticality accidents.
We evaluated the effects of using the half-scan on the exposure of physicians to radiation in intermittent computed tomography (CT) fluoroscopy. For the half-scan, 0°, 90°, 180°, and 270° were used as the angular ranges...We evaluated the effects of using the half-scan on the exposure of physicians to radiation in intermittent computed tomography (CT) fluoroscopy. For the half-scan, 0°, 90°, 180°, and 270° were used as the angular ranges of X-rays on the chest phantom. The ambient dose equivalent was calculated using an optically stimulated luminescence dosemeter at heights of 1600 mm (eye lens height), 1200 mm (chest height), and 800 mm (pelvis height) from the floor. The minimum ambient dose equivalent was observed at 180° for the head and at 90° for the chest and abdomen. Similar results were obtained when calculating the physician's upper extremities. The use of a lead shielding drape reduced radiation exposure by 72% on the head, 73% on the chest, and 33% on the pelvis. In CT-guided IVR of the lung, the use of a lead shielding drape and half-scan is important, depending on the procedural situation.
This study aims to characterize the spatial distribution of natural gamma radiation using NaI(Tl) scintillation spectrometer in the coastal and hinterland regions of Kanyakumari high background natural radiation area, In...This study aims to characterize the spatial distribution of natural gamma radiation using NaI(Tl) scintillation spectrometer in the coastal and hinterland regions of Kanyakumari high background natural radiation area, India. Absorbed dose rate in air (Dair) along the coastal region varied between 38-1757 nGy h-1, with a mean of 214 ± 209 nGy h-1, whereas in the hinterland region Dair ranged between 43 and 367 nGy h-1, with a mean of 107 ± 41 nGy h-1, both mean values were higher than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) world average value of 58 nGy h-1. About 2% of the calculated annual external effective dose of the coastal region were above 1 mSv y-1 and 99% of it were above the UNSCEAR world average value of 0.07 mSv y-1.
This study evaluated the feasibility of a simplified alpha spectroscopy method using a collimator for radionuclidic purity testing at 225Ac production sites. Monte Carlo radiation transport simulations indicated that the...This study evaluated the feasibility of a simplified alpha spectroscopy method using a collimator for radionuclidic purity testing at 225Ac production sites. Monte Carlo radiation transport simulations indicated that the full width at half maximum for the peak due to alpha particles with 4.8 MeV emitted from 226Ra, a potential impurity in cyclotron-produced 225Ac, could be under 300 keV. Experimental results confirmed that this peak was distinctly separated from the primary alpha particle peaks of 225Ac and its progeny. Further simulations were implemented to evaluate the minimum detectable activity for 226Ra in an 225Ac solution with activity between 100 Bq and 10 000 Bq. The findings suggested that at least 0.5% contamination of 226Ra (activity ratio) can be detected by measuring an 225Ac solution over 3600 s. This simplified alpha spectroscopy method shows promise as a viable measurement technique to support future criteria for radionuclidic purity testing at 225Ac production sites.
Neutron spectrometry presents a significant challenge due to the ill posed nature of the unfolding problem, where the neutron energy spectrum cannot be directly extracted from measurements. Traditional unfolding methods,...Neutron spectrometry presents a significant challenge due to the ill posed nature of the unfolding problem, where the neutron energy spectrum cannot be directly extracted from measurements. Traditional unfolding methods, such as Monte Carlo simulations, iterative techniques, Bayesian inference, and the maximum entropy principle, often suffer from substantial limitations, such as high computational cost, sensitivity to noise, numerical instability, difficulty handling incomplete or uncertain data, and a strong dependence on prior assumptions. These constraints have driven a growing interest in alternative solutions. Innovative approaches, based on machine learning (ML), have emerged as a promising substitute to traditional calculations and conventional techniques. In this study, a ML model was developed and trained using database from the International Atomic Energy Agency neutron spectra compendium to perform spectral unfolding from Bonner sphere spectrometer counts rates. Simulation results reveal that the ML based unfolding approach achieves high accuracy and strong generalization capabilities, with reconstructed spectra closely matching reference benchmarks. These findings highlight the potential of ML as a robust and efficient alternative to traditional neutron spectrum unfolding techniques.
As interest in 67Ho increases, the need to accurately calculate the production yields will also increase; this study aims to evaluate theoretically the neutron capture cross-section for the neutron-induced reactions 165H...As interest in 67Ho increases, the need to accurately calculate the production yields will also increase; this study aims to evaluate theoretically the neutron capture cross-section for the neutron-induced reactions 165Ho(n,γ)166Ho and 166mHo(n,γ)167Ho by using the TALYS 1.96/2.0 nuclear code at 25 keV energy. The obtained values are 1.42 b and 2.60 b respectively. The theoretical values obtained are compared with the experimental data extracted from the EXFOR database and the theoretical libraries TENDEL-2023 and JENDL-5 in order to test the validity of the TALYS nuclear code and to seek agreement between the obtained and the experimental values.
The aims of this study was to establish a robust and quantitative methodological basis for the in vitro γ-H2AX assay, validating its dose-response and repair kinetics in both primary peripheral blood mononuclear cells (P...The aims of this study was to establish a robust and quantitative methodological basis for the in vitro γ-H2AX assay, validating its dose-response and repair kinetics in both primary peripheral blood mononuclear cells (PBMCs) and human epithelial type 2 laryngcal carcinoma cells (HEp-2), following exposure to γ radiation doses ranging of 1 to 6 Gy. The mean γ-H2AX foci per cell in both PBMCs and HEp-2 tumor cells increased sharply reaching 52.43 ± 0.61 and 43.96 ± 3.53 foci respectively compared to the control (3,47 ± 0.18) at 6Gy after 30 min post irradiation, reflecting a clear dose-dependent response. However, HEp-2 exhibits a slower overall repair rate than the PBMCs. After 24 h, γ-H2AX phosphorylation levels decreased, indicating substantial DNA repair, though residual foci persisted in PBMCs (11.3 ± 0.26) and HEp-2 cells (13.64 ± 0.33) at 6Gy. The findings suggest that further translational research is warranted to assess its role in clinical biodosimetry and radiotherapy individualization.
Calibration of high-purity germanium (HPGe) detectors for bulk environmental samples is particularly challenging due to complex geometries, heterogeneous matrices, and coincidence summing effects. In this study, we addre...Calibration of high-purity germanium (HPGe) detectors for bulk environmental samples is particularly challenging due to complex geometries, heterogeneous matrices, and coincidence summing effects. In this study, we address these issues by validating a detailed MCNPX model of an N-type HPGe detector against experimental measurements performed with a certified multi-gamma source (12ML01) encapsulated in a 0.45 L Marinelli beaker. The comparison between experimental full-energy peak efficiencies and simulations shows strong agreement, with deviations within 1.2% across the energy range of 59 to 1836 keV. These discrepancies are mainly linked to coincidence summing and uncertainties in dead-layer characterization. The validated model provides a reliable and flexible calibration strategy that extends beyond the limited lifetime of physical standards, offering a practical and cost-effective solution for routine environmental radioactivity monitoring.
Plastic scintillation dosemeters have gained significant interest for invivo dosimetry in high-dose rate brachytherapy (BT) due to their favourable dosimetric properties. However, their clinical utility is limited by Cer...Plastic scintillation dosemeters have gained significant interest for invivo dosimetry in high-dose rate brachytherapy (BT) due to their favourable dosimetric properties. However, their clinical utility is limited by Cerenkov radiation, which can contribute over 50% of the signal, depending on the source position. The current dosemeter based on silica air-core (AC) light-guide was proven to be highly accurate; however, its high light loss and its mechanical rigidity limit its use for invivo BT dosimetry with flexible applicators. In the present work, a novel flexible all-polymer dosemeter with silver-coated polytetrafluoroethylene (Ag-PTFE) light-guide was built and compared to a solid-core light-guide dosemeter (standard dosemeter), using Geant4 Application for Tomographic Emission simulations. A reduction of the Cerenkov noise in the signal of this AC dosemeter was found below 0.3%, independently of the source position. On the other hand, the light collection efficiency was found to be $\sim $40% smaller than in the standard dosemeter. We show how it is possible to further reduce this difference to $\sim $20% and discuss the optimal design of this all-polymer Cerenkov-free dosemeter.
In this study, an optical-model-based elastic scattering (n,el) reaction was investigated, in which a neutron was used as the projectile. The nucleon densities of the $^{127}$I were calculated and applied in the single f...In this study, an optical-model-based elastic scattering (n,el) reaction was investigated, in which a neutron was used as the projectile. The nucleon densities of the $^{127}$I were calculated and applied in the single folding method to obtain interaction potential for the neutron-$^{127}$I reaction as a function of projectile energy. The Skyrme-Hartree-Fock approach was used with the Woods-Saxon potential to calculate nucleon densities by means of the HARTREE-FOCK code. These densities were then used in the Single-Folding model to calculate neutron-$^{127}$I interaction potentials for neutron incident energies of 0.8893 MeV, 2 MeV, and 16.1 MeV. The angular differential cross sections were obtained using TALYS code, with these interaction potentials as input parameters. The evaluated nucleon-nucleus interaction potentials were found to be consistent with other theoretical values reported in the literature. The angular differential cross-section values also showed good agreement with experimental results available in the EXFOR library.
The present study evaluates the efficiency of a system of plantation in mitigating erosion. It was initiated in 2019 in Tifilès watershed (province of Chlef, north-western Algeria). Two investigation sites in a steep sem...The present study evaluates the efficiency of a system of plantation in mitigating erosion. It was initiated in 2019 in Tifilès watershed (province of Chlef, north-western Algeria). Two investigation sites in a steep semi-arid area were used: the first plot was planted with an agroforestry system, while the second was kept bare ground. A reference area was selected in both sites for comparison purposes. 7Be activity in the planted reference site was estimated to be 434 ± 22.67 Bq m-2, whereas it was 497 ± 25.61 Bq m-2 in the unplanted reference site. The relaxation mass depth was found equal to 8.33 kg m-2 in the planted site and 5.55 kg m-2 in the unplanted one. The results show that the planted site is characterized by a lower amount of soil loss than the bare ground plot. This reflects the positive effect of the agroforestry system in controlling erosion in steep areas.
The atmospheric neutrino transport through the Earth, including oscillations in the three-active-flavor scheme, has been simulated using the PHAST (particle hard and soft transport) code system, incorporating the Mikheye...The atmospheric neutrino transport through the Earth, including oscillations in the three-active-flavor scheme, has been simulated using the PHAST (particle hard and soft transport) code system, incorporating the Mikheyev-Smirnov-Wolfenstein effect. We investigated the energy range of 0.1-100 GeV, with a fixed $\delta _{CP} = 280^\circ $, for underwater detectors such as KM3NeT/ORCA and IceCube/DeepCore. Preliminary results identify the 3-10 GeV energy range as promising for the future determination of the neutrino mass hierarchy. The neutrino oscillation implementation in PHAST was validated by comparing our oscillograms with those from the KM3NeT collaboration, showing good agreement. Note, that this study assumes ideal detector conditions, without accounting for the detector response. Further details are presented and discussed in the paper.
149Sm-150Sm and 157Gd-158Gd isotopic shifts of solar planetary materials caused by neutron capture reactions have been utilized to characterize the cosmic-ray exposure (CRE) conditions of the individual materials in spac...149Sm-150Sm and 157Gd-158Gd isotopic shifts of solar planetary materials caused by neutron capture reactions have been utilized to characterize the cosmic-ray exposure (CRE) conditions of the individual materials in space. This paper reviews the results of Sm and Gd isotopic shifts for four kinds of planetary materials: enstatite chondrites (aubrites), iron and iron meteorites, lunar soils, and lunar meteorites, and their application with a view to understanding the relationship between the CRE histories and the evolution processes for individual planetary materials as addressed in my previous studies.
Isotopic studies of the Oklo natural fission reactors have provided very important information to characterize the operating conditions of the individual reactor zones (RZs). Most of the isotopic data of the Oklo RZ mate...Isotopic studies of the Oklo natural fission reactors have provided very important information to characterize the operating conditions of the individual reactor zones (RZs). Most of the isotopic data of the Oklo RZ materials were given more than a quarter of a century ago. Significant progress has recently been made in the instrumental developments of mass spectrometry for isotopic analyses. If more precise isotopic data from the RZ materials were obtained, we may gain new insights into understanding the Oklo phenomenon. There is still much to learn from the Oklo RZs. In this paper, we introduce our new approaches to elucidate the Oklo phenomenon from isotopic studies using state-of-the-art analytical techniques.
Radiat Prot Dosimetry
· 2026 Jun · PMID 41671147
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Radiographic exposure factor selection impacts image quality and radiation dose. This study examined the professionals responsible for conducting X-ray examinations and their training in Ireland. An online survey was dis...Radiographic exposure factor selection impacts image quality and radiation dose. This study examined the professionals responsible for conducting X-ray examinations and their training in Ireland. An online survey was distributed to all practices registered with the Veterinary Council of Ireland. Data were collected on demographics, X-ray equipment, methods of exposure factor selection, confidence in adjustments, and knowledge of detector dose indicators. A total of 120 responses were received. Most clinics use digital systems and rely on technique charts. Many respondents showed limited understanding of detector dose indicators, with 40% reporting poor knowledge and nearly half unaware of their system's capabilities. Exposure factors were rarely adjusted, raising concerns about dose creep. Confidence was higher among less experienced staff. No strong association was found between post-qualification training and confidence. Findings highlight the need for improved training, continuous professional development, and guidelines to optimize practice.
We simulated the mm-wave exposure of a real 60 GHz communication module and validated it using near-field measurements in terms of the incident power density. Next, we numerically evaluated the absorbed power density in...We simulated the mm-wave exposure of a real 60 GHz communication module and validated it using near-field measurements in terms of the incident power density. Next, we numerically evaluated the absorbed power density in a layered tissue model using the finite-difference time-domain technique. The worst-case and realistic exposures were compared with the latest guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and of the Institute of Electrical and Electronics Engineers (IEEE). The worst-case exposure complied with the exposure guidelines for a distance larger than 14.5 mm. Realistic exposure is application dependent and exceeded the limits specified by exposure guidelines for data-intensive applications with duty cycle of 90% at distances smaller than 10.6 mm.
This study investigated the seasonal variations of indoor radon concentrations in parts of cities across different climate zones of China. Using solid state nuclear track detectors (SSNTDs), radon measurements were condu...This study investigated the seasonal variations of indoor radon concentrations in parts of cities across different climate zones of China. Using solid state nuclear track detectors (SSNTDs), radon measurements were conducted over a 12-month period in 171 dwellings located in 15 provincial capital cities. The annual average indoor radon concentration was 81 Bq m-3, with the highest mean level recorded in the Severe Cold Area (99 Bq m-3) and the lowest in the Hot Summer Warm Winter Area (52 Bq m-3). A consistent seasonal pattern was observed across all zones, characterized by elevated concentrations in autumn and winter and lower levels in spring and summer. The mean winter-to-summer concentration ratio was 1.68, indicating a declining trend compared to earlier data from 1994 in China. This trend may be attributed to changes in ventilation practices associated with the widespread adoption of air conditioning. Seasonal correction factors were determined for different climate zones, ranging from 0.80 to 1.43. This study highlights the seasonal fluctuations of indoor radon and the necessity of applying appropriate correction factors when estimating annual average radon concentrations based on short-term measurements to reduce assessment bias. The findings provide critical data and a methodological foundation for accurately assessing and seasonally correcting indoor radon concentrations under diverse climatic conditions in China.
This study aims to evaluate the uranium concentration as an indicator of internal exposure to assess its potential biological effects, including DNA fragmentation and oxidative stress. Blood samples were collected from 8...This study aims to evaluate the uranium concentration as an indicator of internal exposure to assess its potential biological effects, including DNA fragmentation and oxidative stress. Blood samples were collected from 80 individuals (40 residents and 40 from the control group) in Jisr Diyala district, Iraq, for uranium measurements. DNA fragmentation and malondialdehyde (MDA) concentration were estimated using the comet assay and MDA assay, respectively. The uranium concentration in the blood was significantly higher (605.90 ng l-1) in the residents compared to that in the control group (367.04 ng l-1). DNA fragmentation showed a 1.8-fold longer DNA tail, 2.4-fold larger tail area, 2-fold higher %DNA in the tail, and 3.3-fold higher tail moment in the resident group than in the control group. The mean MDA concentration was higher in the resident group (1.250) than in the control group (0.698). A positive correlation was observed between uranium concentration, DNA tail length, DNA tail moment, and MDA concentration. Increased uranium levels underline the importance of studying the associated health risks and biological effects.