Pub Date : 2026-01-29DOI: 10.1016/j.radphyschem.2026.113648
F. Mortazavi , H. Haghighi , P. Tamaddon , A. Ketabi , H. Heli , N. Sattarahmady
Radiotherapy (RT) and sonodynamic therapy (SDT) are reactive oxygen species (ROS)-dependent cancer treatments that suffer from limited efficacy in hypoxic and glutathione (GSH)-rich tumor microenvironments (TMEs). In this study, we developed and characterized a multifunctional polydopamine coated manganese dioxide-gold nanosystem (GMnD) as a dual sensitizer to enhance the therapeutic outcomes of RT and SDT in non-small cell lung carcinoma (NSCLC). Polydopamine coating enhanced the biocompatibility of the nanosystem and imparts stimuli-responsive properties. GMnD exhibited broad optical absorptions (visible to near-infrared), a narrow band gap (1.1 eV), and a high sonothermal conversion efficiency (80.7 %), enabling strong electromagnetic sensitization. On A549 NSCLC cells, the nanosystem in combination with ultrasound (US) and RT significantly increased ROS generation, and induced mitochondrial dysfunction, GSH depletion, catalase-like activity, and sonoporation. These effects led to synergistic cytotoxicity, correlating with mitochondrial membrane potential loss and decreased cell viability. In overall, GMnD presented a promising strategy for improving ROS-mediated combination therapy by modulating the hypoxic TME and disrupting mitochondrial redox balance.
{"title":"Enhanced sono-radio dynamic therapy of non-small cell lung cancer using a polydopamine coated manganese dioxide-gold nanosystem: reactive oxygen species amplification and tumor microenvironment modulation","authors":"F. Mortazavi , H. Haghighi , P. Tamaddon , A. Ketabi , H. Heli , N. Sattarahmady","doi":"10.1016/j.radphyschem.2026.113648","DOIUrl":"10.1016/j.radphyschem.2026.113648","url":null,"abstract":"<div><div>Radiotherapy (RT) and sonodynamic therapy (SDT) are reactive oxygen species (ROS)-dependent cancer treatments that suffer from limited efficacy in hypoxic and glutathione (GSH)-rich tumor microenvironments (TMEs). In this study, we developed and characterized a multifunctional polydopamine coated manganese dioxide-gold nanosystem (GMnD) as a dual sensitizer to enhance the therapeutic outcomes of RT and SDT in non-small cell lung carcinoma (NSCLC). Polydopamine coating enhanced the biocompatibility of the nanosystem and imparts stimuli-responsive properties. GMnD exhibited broad optical absorptions (visible to near-infrared), a narrow band gap (1.1 eV), and a high sonothermal conversion efficiency (80.7 %), enabling strong electromagnetic sensitization. On A549 NSCLC cells, the nanosystem in combination with ultrasound (US) and RT significantly increased ROS generation, and induced mitochondrial dysfunction, GSH depletion, catalase-like activity, and sonoporation. These effects led to synergistic cytotoxicity, correlating with mitochondrial membrane potential loss and decreased cell viability. In overall, GMnD presented a promising strategy for improving ROS-mediated combination therapy by modulating the hypoxic TME and disrupting mitochondrial redox balance.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113648"},"PeriodicalIF":2.8,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-29DOI: 10.1016/j.radphyschem.2026.113664
Jekabs Cirulis, Uldis Rogulis, Nina Mironova-Ulmane, Guntars Zvejnieks, Andris Antuzevics
Stable radiation-induced defects can have significant effects on materials usability in solid state lasers, scintillators, and other devices that may be exposed to ionising radiation. This study investigates several paramagnetic centres in gadolinium gallium garnet (). Analysis of single-crystal electron paramagnetic resonance (EPR) spectra was performed after irradiation with fast neutron radiation. It was determined that paramagnetic centres with highly anisotropic g-factor values are formed and remain stable well above room temperature. The irregular defect symmetry suggests that one of the defects is formed along the direction of cubic lattice diagonal. This defect was attributed to Ge centres resulting from Ga neutron capture coupled with multiple oxygen vacancies. The origin of other paramagnetic centres is discussed based on unusual temperature dependencies of EPR spectra and ab initio calculations.
{"title":"EPR of neutron-radiation-induced defects in Gd3Ga5O12","authors":"Jekabs Cirulis, Uldis Rogulis, Nina Mironova-Ulmane, Guntars Zvejnieks, Andris Antuzevics","doi":"10.1016/j.radphyschem.2026.113664","DOIUrl":"10.1016/j.radphyschem.2026.113664","url":null,"abstract":"<div><div>Stable radiation-induced defects can have significant effects on materials usability in solid state lasers, scintillators, and other devices that may be exposed to ionising radiation. This study investigates several paramagnetic centres in gadolinium gallium garnet (<span><math><mrow><msub><mrow><mi>Gd</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>Ga</mi></mrow><mrow><mn>5</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>12</mn></mrow></msub></mrow></math></span>). Analysis of single-crystal electron paramagnetic resonance (EPR) spectra was performed after irradiation with fast neutron radiation. It was determined that paramagnetic centres with highly anisotropic g-factor values are formed and remain stable well above room temperature. The irregular defect symmetry suggests that one of the defects is formed along the direction of cubic lattice diagonal. This defect was attributed to Ge centres resulting from Ga neutron capture coupled with multiple oxygen vacancies. The origin of other paramagnetic centres is discussed based on unusual temperature dependencies of EPR spectra and ab initio calculations.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113664"},"PeriodicalIF":2.8,"publicationDate":"2026-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146071588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Recently, flat-panel detector (FPD) systems have been developed to display exposure index (EI) values on the console immediately after exposure, thereby enhancing user comprehension. However, differences between examination rooms and bedside imaging can lead to discrepancies in EI values. This study aimed to investigate the relationship between EI and radiographic noise for an indirect-FPD system under varying exposure conditions in digital chest and abdominal radiography. For chest radiography, the following exposure conditions were used: 120 kV with an anti-scatter grid and 70 kV without a grid. For abdominal radiography, the exposure conditions were: 80 kV with a high-ratio (12:1) grid and 80 kV with a low-ratio (5:1) grid. Acrylic phantoms of different thicknesses were used for both chest and abdominal radiography. Radiographic noise was assessed using the Wiener spectrum (WS). For chest radiography, when the incident doses on the imaging detector were identical, the EI values displayed at 120 kV were significantly higher than those at 70 kV. At similar EI values, WS values were lower at 70 kV than at 120 kV. For abdominal radiography, when the incident doses on the imaging detector were identical, the displayed EI values with the high-ratio grid were considerably higher than those with the low-ratio grid. At similar EI values, WS values were lower with the low-ratio grid than with the high-ratio grid. Even when EI values are similar for the same anatomical regions, variations in exposure conditions, such as tube voltage and grid type, affect radiographic noise.
{"title":"Relationship between exposure index and radiographic noise under varying exposure conditions for chest and abdominal radiography","authors":"Nobukazu Tanaka , Yongsu Yoon , Tadamitsu Ideguchi","doi":"10.1016/j.radphyschem.2026.113676","DOIUrl":"10.1016/j.radphyschem.2026.113676","url":null,"abstract":"<div><div>Recently, flat-panel detector (FPD) systems have been developed to display exposure index (EI) values on the console immediately after exposure, thereby enhancing user comprehension. However, differences between examination rooms and bedside imaging can lead to discrepancies in EI values. This study aimed to investigate the relationship between EI and radiographic noise for an indirect-FPD system under varying exposure conditions in digital chest and abdominal radiography. For chest radiography, the following exposure conditions were used: 120 kV with an anti-scatter grid and 70 kV without a grid. For abdominal radiography, the exposure conditions were: 80 kV with a high-ratio (12:1) grid and 80 kV with a low-ratio (5:1) grid. Acrylic phantoms of different thicknesses were used for both chest and abdominal radiography. Radiographic noise was assessed using the Wiener spectrum (WS). For chest radiography, when the incident doses on the imaging detector were identical, the EI values displayed at 120 kV were significantly higher than those at 70 kV. At similar EI values, WS values were lower at 70 kV than at 120 kV. For abdominal radiography, when the incident doses on the imaging detector were identical, the displayed EI values with the high-ratio grid were considerably higher than those with the low-ratio grid. At similar EI values, WS values were lower with the low-ratio grid than with the high-ratio grid. Even when EI values are similar for the same anatomical regions, variations in exposure conditions, such as tube voltage and grid type, affect radiographic noise.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113676"},"PeriodicalIF":2.8,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-28DOI: 10.1016/j.radphyschem.2026.113679
Zhipeng Huo , Yidong Lu , Jie Zhang , Guoqiang Zhong
Gd2O3 nanospheres with three controlled sizes were synthesized via a homogeneous precipitation method. Both synthesized and commercial Gd2O3 fillers were employed as bifunctional neutron and gamma radiation absorbing agents to fabricate radiation shielding materials. FESEM confirmed the nanospherical morphology of synthesized Gd2O3 fillers. HRTEM and SEAD indicate that all Gd2O3 fillers are polycrystalline. HRTEM confirmed that the synthesized Gd2O3 fillers have (321), (400), and (521) exposed crystal planes, while the commercial Gd2O3 fillers have (222) exposed crystal planes, aligning with the corresponding XRD patterns. FESEM of fracture surfaces revealed a more uniform distribution of synthesized Gd2O3 nanosphere fillers within the HDPE matrix compared to the irregularly shaped commercial Gd2O3 fillers. The high specific surface area and superior dispersibility of synthesized Gd2O3 fillers enhanced the overall performance of the nanocomposite. Notably, nanocomposites containing synthesized Gd2O3-Ⅱ nanospheres with an average size of 82.6 ± 14.2 nm achieved a neutron and gamma shielding rates of 99.3 % and 73.7 %, the Σ, μ, μm, HVL are 0.239 cm−1, 0.092 cm−1, 0.076 cm2/g, 7.57 cm, correspondingly, at a thickness of 15 cm, demonstrating its potential for high-performance radiation shielding applications. This study provides a novel strategy for designing lightweight, high-performance radiation shielding materials for nuclear facilities, aerospace applications, radioactive waste conditioning and relative fields.
{"title":"Size-controlled Gd2O3 nanospheres reinforced B4C/HDPE nanocomposites for neutron and gamma-ray complex radiation shielding","authors":"Zhipeng Huo , Yidong Lu , Jie Zhang , Guoqiang Zhong","doi":"10.1016/j.radphyschem.2026.113679","DOIUrl":"10.1016/j.radphyschem.2026.113679","url":null,"abstract":"<div><div>Gd<sub>2</sub>O<sub>3</sub> nanospheres with three controlled sizes were synthesized via a homogeneous precipitation method. Both synthesized and commercial Gd<sub>2</sub>O<sub>3</sub> fillers were employed as bifunctional neutron and gamma radiation absorbing agents to fabricate radiation shielding materials. FESEM confirmed the nanospherical morphology of synthesized Gd<sub>2</sub>O<sub>3</sub> fillers. HRTEM and SEAD indicate that all Gd<sub>2</sub>O<sub>3</sub> fillers are polycrystalline. HRTEM confirmed that the synthesized Gd<sub>2</sub>O<sub>3</sub> fillers have (321), (400), and (521) exposed crystal planes, while the commercial Gd<sub>2</sub>O<sub>3</sub> fillers have (222) exposed crystal planes, aligning with the corresponding XRD patterns. FESEM of fracture surfaces revealed a more uniform distribution of synthesized Gd<sub>2</sub>O<sub>3</sub> nanosphere fillers within the HDPE matrix compared to the irregularly shaped commercial Gd<sub>2</sub>O<sub>3</sub> fillers. The high specific surface area and superior dispersibility of synthesized Gd<sub>2</sub>O<sub>3</sub> fillers enhanced the overall performance of the nanocomposite. Notably, nanocomposites containing synthesized Gd<sub>2</sub>O<sub>3</sub>-Ⅱ nanospheres with an average size of 82.6 ± 14.2 nm achieved a neutron and gamma shielding rates of 99.3 % and 73.7 %, the <em>Σ</em>, <em>μ</em>, <em>μ</em><sub>m</sub>, HVL are 0.239 cm<sup>−1</sup>, 0.092 cm<sup>−1</sup>, 0.076 cm<sup>2</sup>/g, 7.57 cm, correspondingly, at a thickness of 15 cm, demonstrating its potential for high-performance radiation shielding applications. This study provides a novel strategy for designing lightweight, high-performance radiation shielding materials for nuclear facilities, aerospace applications, radioactive waste conditioning and relative fields.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113679"},"PeriodicalIF":2.8,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146072397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-23DOI: 10.1016/j.radphyschem.2026.113663
Ayman Abu Ghazal , Rawand Alakash , Feras Afaneh
Spent nuclear fuel (SNF) transport and dry-storage containers are crucial for guaranteeing the safe confinement and radiation shielding of highly radioactive materials at the conclusion of the nuclear fuel cycle. This work presents a comprehensive Monte Carlo investigation of a novel Tri-Layer Adaptive Composite System (TACS) developed for radiation shielding in SNF transport and dry-storage casks. The proposed architecture adopts a functionally graded design composed of three optimized layers: a Refractory High-Entropy Alloy (RHEA) inner layer providing structural integrity and initial gamma attenuation, a Hydrogenated Boron Nitride (HBN) composite layer serving as the primary neutron moderator and absorber, and an outer Tungsten–Metallic Glass Matrix Composite (W-MGMC) layer delivering further suppression of residual gamma and neutron radiation. Radiation transport simulations were performed using MCNP5, modeling a homogenized pressurized water reactor (PWR) mixed-oxide (MOX) spent fuel assembly with a heavy-metal loading of 0.492 tHM and a representative burnup of 50 GWd tHM−1. Conservative, bounding source terms were employed, assuming 137Cs as the dominant gamma-emitting radionuclide and 244Cm as the primary neutron source via spontaneous fission, for cooling times up to 50 years. The results show smooth and monotonic attenuation of both photon and neutron fields across the multilayer system, with no localized dose-rate hot spots. Energy-dependent total microscopic photon cross-section analyses confirm substantial interaction probabilities in the high-Z RHEA and W-MGMC layers across the relevant energy range, explaining the rapid suppression of gamma flux and dose observed within these regions. At the same time, HBN exhibits minimal photon interaction consistent with its low-Z composition. Half-value layer (HVL) analysis further quantifies the shielding efficiency, revealing that RHEA and W-MGMC exhibit the smallest gamma HVLs (≈0.8 cm). In contrast, HBN provides the lowest neutron HVL (≈1.5 cm), confirming its dominant role in fast-neutron removal. At the cask surface, the TACS configuration achieves a total dose rate of approximately 0.10 mSv h−1, corresponding to a safety margin of about 20 × below the IAEA SSR-6 transport limit. Comparative benchmarking against conventional Fe–PE–Pb and steel–air–concrete shielding configurations demonstrates the superior shielding efficiency and compactness of the proposed system, particularly for neutron-dominated, high-burnup MOX fuel inventories.
{"title":"Monte Carlo evaluation of a novel functionally graded tri-layer composite system for MOX spent nuclear fuel casks","authors":"Ayman Abu Ghazal , Rawand Alakash , Feras Afaneh","doi":"10.1016/j.radphyschem.2026.113663","DOIUrl":"10.1016/j.radphyschem.2026.113663","url":null,"abstract":"<div><div>Spent nuclear fuel (SNF) transport and dry-storage containers are crucial for guaranteeing the safe confinement and radiation shielding of highly radioactive materials at the conclusion of the nuclear fuel cycle. This work presents a comprehensive Monte Carlo investigation of a novel Tri-Layer Adaptive Composite System (TACS) developed for radiation shielding in SNF transport and dry-storage casks. The proposed architecture adopts a functionally graded design composed of three optimized layers: a Refractory High-Entropy Alloy (RHEA) inner layer providing structural integrity and initial gamma attenuation, a Hydrogenated Boron Nitride (HBN) composite layer serving as the primary neutron moderator and absorber, and an outer Tungsten–Metallic Glass Matrix Composite (W-MGMC) layer delivering further suppression of residual gamma and neutron radiation. Radiation transport simulations were performed using MCNP5, modeling a homogenized pressurized water reactor (PWR) mixed-oxide (MOX) spent fuel assembly with a heavy-metal loading of 0.492 tHM and a representative burnup of 50 GWd tHM<sup>−1</sup>. Conservative, bounding source terms were employed, assuming <sup>137</sup>Cs as the dominant gamma-emitting radionuclide and <sup>244</sup>Cm as the primary neutron source via spontaneous fission, for cooling times up to 50 years. The results show smooth and monotonic attenuation of both photon and neutron fields across the multilayer system, with no localized dose-rate hot spots. Energy-dependent total microscopic photon cross-section analyses confirm substantial interaction probabilities in the high-Z RHEA and W-MGMC layers across the relevant energy range, explaining the rapid suppression of gamma flux and dose observed within these regions. At the same time, HBN exhibits minimal photon interaction consistent with its low-Z composition. Half-value layer (HVL) analysis further quantifies the shielding efficiency, revealing that RHEA and W-MGMC exhibit the smallest gamma HVLs (≈0.8 cm). In contrast, HBN provides the lowest neutron HVL (≈1.5 cm), confirming its dominant role in fast-neutron removal. At the cask surface, the TACS configuration achieves a total dose rate of approximately 0.10 mSv h<sup>−1</sup>, corresponding to a safety margin of about 20 × below the IAEA SSR-6 transport limit. Comparative benchmarking against conventional Fe–PE–Pb and steel–air–concrete shielding configurations demonstrates the superior shielding efficiency and compactness of the proposed system, particularly for neutron-dominated, high-burnup MOX fuel inventories.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113663"},"PeriodicalIF":2.8,"publicationDate":"2026-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146047884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.radphyschem.2026.113656
Tahir E. Adreani , Ibrahim I. Suliman , Hajo Idriss , A. Sulieman , M. Alkhorayef , D. Bradley
Artificial neural network (ANN) and multilinear regression (MLR) models are widely recognized for their effectiveness in predicting the dynamics of industrial and natural phenomena. In this study, both multiple regression and ANN were employed to forecast radioactivity levels in regions affected by gold mining in Eastern Sudan. We developed multi-regression and ANN models using Python scripts in a Linux environment. The results were tested and validated against background radiation measurements in an area with naturally occurring radioactive materials (NORM) in Eastern Sudan. These findings were compared with the activity concentrations of the soil samples measured using high-purity germanium (HPGe) gamma spectrometry. The study revealed that The ANN model demonstrated superior predictive capabilities for 226Ra and 232Th activity concentrations compared to MLR, owing to ANN's ability to model nonlinear relationships in environmental radioactivity data. Although the multilinear regression performed better at 40K because of its linear soil dependency, the ANN achieved higher correlation coefficients overall. These results confirm that ANN-based methodologies can effectively predict radionuclide distributions and improve environmental radiation assessment.
{"title":"Artificial neural network (ANN) vs multilinear regression (MLR) models to predict naturally occurring radioactivity (NORM) in the gold mining area in eastern Sudan","authors":"Tahir E. Adreani , Ibrahim I. Suliman , Hajo Idriss , A. Sulieman , M. Alkhorayef , D. Bradley","doi":"10.1016/j.radphyschem.2026.113656","DOIUrl":"10.1016/j.radphyschem.2026.113656","url":null,"abstract":"<div><div>Artificial neural network (ANN) and multilinear regression (MLR) models are widely recognized for their effectiveness in predicting the dynamics of industrial and natural phenomena. In this study, both multiple regression and ANN were employed to forecast radioactivity levels in regions affected by gold mining in Eastern Sudan. We developed multi-regression and ANN models using Python scripts in a Linux environment. The results were tested and validated against background radiation measurements in an area with naturally occurring radioactive materials (NORM) in Eastern Sudan. These findings were compared with the activity concentrations of the soil samples measured using high-purity germanium (HPGe) gamma spectrometry. The study revealed that The ANN model demonstrated superior predictive capabilities for <sup>226</sup>Ra and <sup>232</sup>Th activity concentrations compared to MLR, owing to ANN's ability to model nonlinear relationships in environmental radioactivity data. Although the multilinear regression performed better at <sup>40</sup>K because of its linear soil dependency, the ANN achieved higher correlation coefficients overall. These results confirm that ANN-based methodologies can effectively predict radionuclide distributions and improve environmental radiation assessment.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113656"},"PeriodicalIF":2.8,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-22DOI: 10.1016/j.radphyschem.2026.113661
Hui-Chao Li , Dan-Dan Su , Xiao-Bin Li , Jun-Liang Guo , Feng-Chen Li , Shu-Qi Meng
In pressurized water reactors (PWRs), neutron-induced water radiolysis is a key factor in accelerating the oxidation of zirconium alloy cladding. In this study, the neutron-induced water radiolysis process from 1 keV to 5 MeV at 573 K and 15.5 MPa was simulated using the reactive force field molecular dynamics (ReaxFF-MD) method. The results show that the G-values of molecular products (H2, H2O2) decrease with increasing neutron energy, while the G-value of free radicals (•OH, H•) increase, demonstrating the linear energy transfer (LET) effect. The analysis of the microscopic mechanism reveals that low-energy primary knock-on atoms (PKAs) forms a dense track, and the G-value evolution follows a delayed-onset rapid growth pattern. Medium energy PKAs trigger a compression-rebound effect, and forms a transition track. High-energy PKAs penetrate in an inefficient energy-transfer mode with dispersed energy, and the G-value rapidly reaches the peak and then decreases. This study elucidates the intrinsic mechanism of the LET effect from the atomic scale, and provides a theoretical basis for the study of zirconium alloy oxidation and the construction of material damage model.
{"title":"Dynamics of neutron-induced water radiolysis in high-temperature, high-pressure water relevant to PWR primary coolant","authors":"Hui-Chao Li , Dan-Dan Su , Xiao-Bin Li , Jun-Liang Guo , Feng-Chen Li , Shu-Qi Meng","doi":"10.1016/j.radphyschem.2026.113661","DOIUrl":"10.1016/j.radphyschem.2026.113661","url":null,"abstract":"<div><div>In pressurized water reactors (PWRs), neutron-induced water radiolysis is a key factor in accelerating the oxidation of zirconium alloy cladding. In this study, the neutron-induced water radiolysis process from 1 keV to 5 MeV at 573 K and 15.5 MPa was simulated using the reactive force field molecular dynamics (ReaxFF-MD) method. The results show that the <em>G</em>-values of molecular products (H<sub>2</sub>, H<sub>2</sub>O<sub>2</sub>) decrease with increasing neutron energy, while the <em>G</em>-value of free radicals (•OH, H•) increase, demonstrating the linear energy transfer (LET) effect. The analysis of the microscopic mechanism reveals that low-energy primary knock-on atoms (PKAs) forms a dense track, and the <em>G</em>-value evolution follows a delayed-onset rapid growth pattern. Medium energy PKAs trigger a compression-rebound effect, and forms a transition track. High-energy PKAs penetrate in an inefficient energy-transfer mode with dispersed energy, and the <em>G</em>-value rapidly reaches the peak and then decreases. This study elucidates the intrinsic mechanism of the LET effect from the atomic scale, and provides a theoretical basis for the study of zirconium alloy oxidation and the construction of material damage model.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113661"},"PeriodicalIF":2.8,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146033170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The standard-less IM-NAA approach using research reactors requires characterization of the different irradiation sites with respect to neutron flux parameters, specifically the sub-cadmium to epithermal flux ratio (f) and the epithermal neutron flux shape factor (α). The flux characterization was performed at two research reactor facilities at BARC, Mumbai: the outer core irradiation position (H7) of the Apsara-U reactor and the Pneumatic Carrier Facility (PCF) of the Dhruva reactor. The accuracy and robustness of the developed methodology was validated using certified reference materials (CRMs). The optimized IM-NAA methodology was subsequently employed for the comprehensive chemical characterization of different steel samples relevant to advanced reactor technology. The uncertainty associated with IM-NAA measurements was rigorously evaluated, accounting for nuclear data parameters (e.g., Q0, k0, ) reactor flux parameters (f, α), and other contributors often neglected in conventional analysis. The work successfully demonstrated that IM-NAA, when implemented with properly characterized flux parameters, provides a reliable, standard-less methodology for the accurate and precise compositional analysis of complex alloys, thereby strengthening quality control and material verification protocols for advanced nuclear technologies.
{"title":"Standard-less IM-NAA for compositional analysis of nuclear reactor materials: Flux characterization and uncertainty evaluation","authors":"S.K. Samanta , Purbali Das , Sonika Gupta , Suparna Sodaye","doi":"10.1016/j.radphyschem.2026.113657","DOIUrl":"10.1016/j.radphyschem.2026.113657","url":null,"abstract":"<div><div>The standard-less IM-NAA approach using research reactors requires characterization of the different irradiation sites with respect to neutron flux parameters, specifically the sub-cadmium to epithermal flux ratio (<em>f</em>) and the epithermal neutron flux shape factor (<em>α</em>). The flux characterization was performed at two research reactor facilities at BARC, Mumbai: the outer core irradiation position (H7) of the Apsara-U reactor and the Pneumatic Carrier Facility (PCF) of the Dhruva reactor. The accuracy and robustness of the developed methodology was validated using certified reference materials (CRMs). The optimized IM-NAA methodology was subsequently employed for the comprehensive chemical characterization of different steel samples relevant to advanced reactor technology. The uncertainty associated with IM-NAA measurements was rigorously evaluated, accounting for nuclear data parameters (e.g., <em>Q</em><sub><em>0</em></sub>, <em>k</em><sub><em>0</em></sub>, <span><math><mrow><mover><msub><mi>E</mi><mi>r</mi></msub><mo>‾</mo></mover></mrow></math></span>) reactor flux parameters (<em>f, α</em>), and other contributors often neglected in conventional analysis. The work successfully demonstrated that IM-NAA, when implemented with properly characterized flux parameters, provides a reliable, standard-less methodology for the accurate and precise compositional analysis of complex alloys, thereby strengthening quality control and material verification protocols for advanced nuclear technologies.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113657"},"PeriodicalIF":2.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-21DOI: 10.1016/j.radphyschem.2026.113658
Omar Bentiane, Omaima Khettabi, Omar Berradi, El Mehdi Sadiki, Fatimaezzahra Bouzzit, Rodouan Touti
Computed Tomography (CT) is a key diagnostic tool in medical imaging, but concerns persist regarding radiation exposure, particularly in repeat or high-dose examinations. The CTDIvol quantifies scanner output but does not accurately represent the patient dose. The Size-Specific Dose Estimate (SSDE) provides a more clinically relevant patient-specific dose estimate by accounting for body size and composition. This study aims to quantify the differences between CTDIvol and SSDE in adult thoraco-abdominopelvic and abdominopelvic CT scans, compare manual and automatic methods of patient size estimation, and evaluate organ doses. A retrospective review was conducted on 52 adult CT scans (thoraco-abdominopelvic and abdominopelvic). Four patient-size metrics were collected: the manually measured effective diameter (Deff-M), the automatically averaged z-axis effective diameter (Deff-AZ), and two water-equivalent diameters (Dw-E and Dw-AZ). The SSDE values were calculated according to AAPM TG-204 and TG-220. The organ doses were estimated with IndoseCT based on Monte Carlo-derived correlations. The mean CTDIvol was 13.0 ± 3.6 mGy, with SSDE values 31–37 % higher across all methods. Deff-AZ was 4.7 % greater than Deff-M, while Dw-E and Dw-AZ showed near-perfect agreement. The liver, kidneys, and bladder received the highest doses (>15 mGy) as they are directly irradiated, whereas radiosensitive organs outside the primary scan field, such as the thyroid and eyes, received measurable scatter doses. SSDE provides a more accurate representation of patient radiation dose than CTDIvol and should be integrated into routine CT protocols. Among the evaluated size metrics, attenuation-based Dw proved to be the most robust and reproducible. Incorporating organ-dose estimations and SSDE into clinical practice can enhance patient safety, optimize imaging protocols, and support compliance with radiation protection regulations.
{"title":"Beyond CTDIvol: Patient-specific SSDE and organ dose assessment in routine adult CT practice","authors":"Omar Bentiane, Omaima Khettabi, Omar Berradi, El Mehdi Sadiki, Fatimaezzahra Bouzzit, Rodouan Touti","doi":"10.1016/j.radphyschem.2026.113658","DOIUrl":"10.1016/j.radphyschem.2026.113658","url":null,"abstract":"<div><div>Computed Tomography (CT) is a key diagnostic tool in medical imaging, but concerns persist regarding radiation exposure, particularly in repeat or high-dose examinations. The CTDI<sub>vol</sub> quantifies scanner output but does not accurately represent the patient dose. The Size-Specific Dose Estimate (SSDE) provides a more clinically relevant patient-specific dose estimate by accounting for body size and composition. This study aims to quantify the differences between CTDI<sub>vol</sub> and SSDE in adult thoraco-abdominopelvic and abdominopelvic CT scans, compare manual and automatic methods of patient size estimation, and evaluate organ doses. A retrospective review was conducted on 52 adult CT scans (thoraco-abdominopelvic and abdominopelvic). Four patient-size metrics were collected: the manually measured effective diameter (D<sub>eff-M</sub>), the automatically averaged z-axis effective diameter (D<sub>eff-AZ</sub>), and two water-equivalent diameters (D<sub>w-E</sub> and D<sub>w-AZ</sub>). The SSDE values were calculated according to AAPM TG-204 and TG-220. The organ doses were estimated with <em>IndoseCT</em> based on Monte Carlo-derived correlations. The mean CTDI<sub>vol</sub> was 13.0 ± 3.6 mGy, with SSDE values 31–37 % higher across all methods. D<sub>eff-AZ</sub> was 4.7 % greater than D<sub>eff-M</sub>, while D<sub>w-E</sub> and D<sub>w-AZ</sub> showed near-perfect agreement. The liver, kidneys, and bladder received the highest doses (>15 mGy) as they are directly irradiated, whereas radiosensitive organs outside the primary scan field, such as the thyroid and eyes, received measurable scatter doses. SSDE provides a more accurate representation of patient radiation dose than CTDI<sub>vol</sub> and should be integrated into routine CT protocols. Among the evaluated size metrics, attenuation-based D<sub>w</sub> proved to be the most robust and reproducible. Incorporating organ-dose estimations and SSDE into clinical practice can enhance patient safety, optimize imaging protocols, and support compliance with radiation protection regulations.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113658"},"PeriodicalIF":2.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-21DOI: 10.1016/j.radphyschem.2026.113640
Ahmed A. Abdou Elabbasy , Ahmed M. El-Khayatt , Mahmoud Elsayed , Hesham M.H. Zakaly , A. Alkaoud , Islam M. Nabil , Islam N. Fathy , Alaa M. Rashad , Manar Ali
This study examined the mechanical properties and γ-ray radiation shielding performance of different ultra high-performance concrete (UHPC) mixes incorporating individual and hybrid combinations of steel (SF), polyvinyl alcohol (PVA), polypropylene (PP), and natural jute fibers (JF). Radiation attenuation was assessed through experimental testing and validated using Monte Carlo (MC) simulations and Phy-X software. Results indicated that the control UHPC mix with steel fibers alone achieved the highest compressive strength of 140 MPa at curing age of 28 days. In comparison with this SF-reinforced control mix, the hybrid fiber mixtures (SF + PVA, SF + PP, SF + JF, and SF + PP + PVA + JF) exhibited reductions in compressive strength of approximately 12.4 %, 11.6 %, 15.7 %, and 21.1 %, respectively, at the same age. Tensile and flexural strengths followed a similar trend of reduction with hybrid fiber incorporation. Relative to the tensile strength value of the control mix (10 MPa), hybrid fiber combinations (SF + PVA, SF + PP, SF + JF, and SF + PP + PVA + JF) resulted in tensile strength reductions of approximately 4 %, 5 %, 8 %, and 8 %. Similarly, their flexural strengths were notably decreased by about 9.6 %, 18.4 %, 22 %, and 24.4 %, respectively, when compared to the control mix that achieved 25 MPa with only SF. While steel fibers remain the most effective, incorporating natural or synthetic fibers like jute and polypropylene can provide acceptable γ-attenuation performance, with potential advantages in cost, flexibility, and sustainability. Hybrid combinations offer a promising balance, especially when multi-functionality (e.g., mechanical strength and γ-radiation shielding) is desired. The key novelty aspect of this work lies in examining fiber type as the main affecting variable on the radiation shielding behavior of UHPC, while combining experimental testing with MC simulation and Phy-X software for radiation shielding assessment.
{"title":"Assessment of mechanical properties and radiation shielding efficiency of fiber-reinforced ultra high-performance concrete: Experimental and simulation analysis","authors":"Ahmed A. Abdou Elabbasy , Ahmed M. El-Khayatt , Mahmoud Elsayed , Hesham M.H. Zakaly , A. Alkaoud , Islam M. Nabil , Islam N. Fathy , Alaa M. Rashad , Manar Ali","doi":"10.1016/j.radphyschem.2026.113640","DOIUrl":"10.1016/j.radphyschem.2026.113640","url":null,"abstract":"<div><div>This study examined the mechanical properties and γ-ray radiation shielding performance of different ultra high-performance concrete (UHPC) mixes incorporating individual and hybrid combinations of steel (SF), polyvinyl alcohol (PVA), polypropylene (PP), and natural jute fibers (JF). Radiation attenuation was assessed through experimental testing and validated using Monte Carlo (MC) simulations and Phy-X software. Results indicated that the control UHPC mix with steel fibers alone achieved the highest compressive strength of 140 MPa at curing age of 28 days. In comparison with this SF-reinforced control mix, the hybrid fiber mixtures (SF + PVA, SF + PP, SF + JF, and SF + PP + PVA + JF) exhibited reductions in compressive strength of approximately 12.4 %, 11.6 %, 15.7 %, and 21.1 %, respectively, at the same age. Tensile and flexural strengths followed a similar trend of reduction with hybrid fiber incorporation. Relative to the tensile strength value of the control mix (10 MPa), hybrid fiber combinations (SF + PVA, SF + PP, SF + JF, and SF + PP + PVA + JF) resulted in tensile strength reductions of approximately 4 %, 5 %, 8 %, and 8 %. Similarly, their flexural strengths were notably decreased by about 9.6 %, 18.4 %, 22 %, and 24.4 %, respectively, when compared to the control mix that achieved 25 MPa with only SF. While steel fibers remain the most effective, incorporating natural or synthetic fibers like jute and polypropylene can provide acceptable γ-attenuation performance, with potential advantages in cost, flexibility, and sustainability. Hybrid combinations offer a promising balance, especially when multi-functionality (e.g., mechanical strength and γ-radiation shielding) is desired. The key novelty aspect of this work lies in examining fiber type as the main affecting variable on the radiation shielding behavior of UHPC, while combining experimental testing with MC simulation and Phy-X software for radiation shielding assessment.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"243 ","pages":"Article 113640"},"PeriodicalIF":2.8,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146014443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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