Radiation Physics and Chemistry最新文献

{"title":"Automatic identification and quantification of γ-emitting radionuclides with spectral variability using a hybrid Machine Learning unmixing method","authors":"Dinh Triem Phan ,&nbsp;Jérôme Bobin ,&nbsp;Cheick Thiam ,&nbsp;Christophe Bobin","doi":"10.1016/j.radphyschem.2025.112654","DOIUrl":"10.1016/j.radphyschem.2025.112654","url":null,"abstract":"<div><div>Automatic identification and quantification of γ-emitting radionuclides, considering the spectral deformation due to γ-interactions in the radioactive source environment, is a demanding challenge in the field of nuclear physics. In this context, this paper presents a hybrid unmixing approach combining a pre-trained machine learning model (autoencoder) to capture spectral deformations and a model selection technique based on statistical testing to identify the radionuclides present in a radioactive source and quantify their mixing weights. The identification process of radionuclides is based on a sequential selection algorithm using a likelihood ratio test depending on the expected false positives. Basically, this method aims to minimize the number of radionuclides in an initial radionuclide library containing characteristic γ-spectra of each γ-emitter to be tested. The robustness of decision-making with this approach and the quantification performance are investigated with Monte Carlo simulations involving up to 12 radionuclides to be tested, according to different mixture scenarios with increasing complexity and various statistics. The false positive rates obtained with the hybrid unmixing approach are close to the expected values. In general, the quantification results are similar to the case when the radionuclides present in the source and spectral signatures are known. This highlights the effectiveness of this novel hybrid unmixing approach for the automatic identification and quantification of gamma-ray emitting radionuclides with spectral variability.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112654"},"PeriodicalIF":2.8,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580374","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}

{"title":"Chemical mechanism in gold nanoparticles radiosensitization: A Monte Carlo simulation study","authors":"Joana Antunes ,&nbsp;Hans Rabus ,&nbsp;Filipa Mendes ,&nbsp;António Paulo ,&nbsp;Jorge M. Sampaio","doi":"10.1016/j.radphyschem.2025.112637","DOIUrl":"10.1016/j.radphyschem.2025.112637","url":null,"abstract":"<div><div>Gold nanoparticles (AuNPs) can enhance radiotherapy efficacy via physical and chemical mechanisms, with their individual contributions varying depending on the type of radiation. Moreover, AuNP-enhanced radiotherapy efficacy depends also on nanoparticle size and number, and on a complex dynamics of reactive oxygen species (ROS) production. Monte Carlo simulations of irradiating a single nanoparticle with Co-60 <span><math><mi>γ</mi></math></span>-rays, 160 kVp X-rays, 14 MeV and 200 MeV proton beam were performed to estimate the enhancement of ROS production. The enhancement was also evaluated as a function of the NP diameter. The simulation setup was such that lateral charged particle equilibrium (CPE) was achieved, and the results were normalized to the fluence of the incident radiation field. The findings confirm previous reports that ROS enhancement is greater for low LET protons compared to high LET protons and for low-energy X-rays compared to Co-60 <span><math><mi>γ</mi></math></span>-rays. However, the enhancement due to a single AuNP is found to be orders of magnitude smaller if CPE conditions prevail. This statement also holds for the estimated enhancement for multiple AuNPs at mass fractions in the percent level. The dependence of ROS enhancement on NP size varies with the type of radiation, following distinct trends: an almost cubic relationship for low-energy X-rays, a quadratic relationship for Co-60 and 200 MeV protons, and an intermediate relationship for 14 MeV protons. These trends correspond closely to the yield of secondary electrons emitted by the NPs, which drive ROS production. This study provides insights into the mechanisms of ROS enhancement, contributing to the optimization of nanoparticle-enhanced radiation therapy.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112637"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digital alpha-electron discrimination with a silicon detector and its application as an auxiliary detector in the alpha TOF spectrometer","authors":"M. Azizi ,&nbsp;B. Ghasemi ,&nbsp;O. Kakuee ,&nbsp;A. Biganeh","doi":"10.1016/j.radphyschem.2025.112680","DOIUrl":"10.1016/j.radphyschem.2025.112680","url":null,"abstract":"<div><div>Alpha Time-Of-Flight (A-TOF) spectroscopy is commonly used to measure alpha particles in high-energy resolution. To minimize interference from background radiation and prevent random TOF registrations during long-time measurements, specific strategies are necessary. One effective approach involves incorporating an auxiliary detector at the end of the flight vacuum tube. In this configuration, the alpha particle is registered only when detected by the auxiliary detector at the end of its trajectory. In this work, an ion-implanted silicon detector is used as an auxiliary detector to discriminate alpha from other radiations, such as electrons produced from photon interactions with materials in the structure of the TOF spectrometer. A simple setup using a digitizer is presented to investigate the ability of the silicon detector to discriminate between alpha particles and electrons. This technique distinguishes between alpha and electron particles using the charge integration method, implemented in the DPP-PSD firmware of the digitizer. The performance of the setup was experimentally evaluated using a²⁴¹Am source, which emits both alpha particles and conversion electrons. The results demonstrated that it is possible to effectively distinguish between alpha particles and electrons through charge comparisons of the sampled signals from the silicon detector. Thus, this technique can contribute to the development of A-TOF spectrometers by minimizing the interference from background radiation and random noise in time registrations during long-term measurements.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112680"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562763","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}

{"title":"Real-time CNN-based object detection of prohibited items for X-ray security screening","authors":"Junsung Park ,&nbsp;Geunyoung An ,&nbsp;Byeong-No Lee ,&nbsp;Hee Seo","doi":"10.1016/j.radphyschem.2025.112681","DOIUrl":"10.1016/j.radphyschem.2025.112681","url":null,"abstract":"<div><div>In homeland security, X-ray security scanners are essential for detecting contraband, including weapons, drugs, and hazardous materials. However, detection accuracy might be limited when items overlap or are concealed in complex baggage configurations. To address this issue, we developed a one-stage convolutional neural network (CNN) object detection model based on the You Only Look Once (YOLO) architecture, which employs a CSP-Darknet53 backbone for feature extraction. This model was designed for X-ray security scanners to enhance the detection of prohibited items in carry-on baggage, even under challenging conditions. The model was trained on a dataset comprising 6000 annotated X-ray images of suitcases, simulating real-world baggage scenarios with varying degrees of object overlap. Prohibited items were categorized into 22 classes based on the relevant International Civil Aviation Organization (ICAO) standards and Korean law, covering sharp objects (e.g., scissors, knives), weapons (e.g., guns, shurikens), and hazardous materials (e.g., liquids, flammables). To improve generalization, extensive image augmentation techniques were applied during training. Performance was evaluated using AP@50 (average precision at an IoU threshold of 0.5) and the F1-score, averaging 0.87 and 0.86 across all classes, respectively. Additionally, the average inference time per baggage item was 12.58 ms, making the system suitable for real-time airport security applications. These results demonstrate the potential of artificial intelligence (AI)-based security screening as a practical, high-speed detection solution for real-world airport security applications. This study addresses occlusion challenges in security screening by integrating multi-stage object overlap handling and dual-energy imaging. Compared to existing approaches, it could have higher applicability in complex baggage screening environments. While the model effectively detects structured prohibited items, further improvements are needed to identify non-rigid contraband, such as explosives and narcotics. Future research will explore dual-energy signal-based algorithms to enhance the detection capability of illicit substances.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112681"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580725","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}

{"title":"Comparative analysis of single-walled, double-walled, and multi-walled carbon nanotube-reinforced Poly(2,5-benzimidazole) composites: Enhanced structural and thermal stability for radiation shielding in low Earth Orbit","authors":"Lynndle Square ,&nbsp;Bosco Oryema ,&nbsp;Pako Mafoko ,&nbsp;Ernst Ellis ,&nbsp;Henriette Vorster","doi":"10.1016/j.radphyschem.2025.112658","DOIUrl":"10.1016/j.radphyschem.2025.112658","url":null,"abstract":"<div><div>Poly(2,5-benzimidazole) (ABPBI) composites reinforced with 1 wt% single-wall (SWCNT), double-wall (DWCNT), and multi-wall (MWCNT) carbon nanotubes were synthesised and evaluated for radiation shielding applications in Low Earth Orbit (LEO). The structural and thermal properties of these nanocomposites were characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Atomic Force Microscopy (AFM). FTIR analysis confirmed the retention of ABPBI's characteristic molecular structure across all nanocomposites, with ABPBI/DWCNT exhibiting the strongest molecular bonding. Thermal analysis demonstrated exceptional stability, with ∼95% weight retention at 400 °C and ∼70% at 900 °C, suggesting suitability for high-temperature applications.</div><div>To assess radiation resistance, 3 MeV He²⁺ ion bombardment was performed on ABPBI/DWCNT nanocomposites. Post-irradiation FTIR and XRD results indicated mild molecular degradation but preserved semi-crystalline structures, demonstrating strong radiation tolerance. AFM analysis further revealed nanoscale surface modifications, providing insights into radiation-induced morphological changes and confirming the structural resilience of ABPBI-based nanocomposites. The results suggest that ABPBI/DWCNT exhibits promising mechanical integrity, thermal stability, and radiation resistance for space applications.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112658"},"PeriodicalIF":2.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tm-concentration dependence on photoluminescence and scintillation properties of Tm-doped Gd2SrAl2O7 single crystals","authors":"Keiichiro Miyazaki,&nbsp;Daisuke Nakauchi,&nbsp;Takumi Kato,&nbsp;Noriaki Kawaguchi,&nbsp;Takayuki Yanagida","doi":"10.1016/j.radphyschem.2025.112672","DOIUrl":"10.1016/j.radphyschem.2025.112672","url":null,"abstract":"<div><div>Gd₂SrAl₂O₇ single crystals doped with various Tm-concentration (0, 0.1, 0.3, 1, and 3%) were grown by the optical floating zone method. Tm-concentration dependence on the photoluminescence (PL) and scintillation properties were investigated in Tm-doped Gd₂SrAl₂O₇ single crystals. In PL and scintillation, all the samples showed several emission peaks due to 4f-4f transitions of Tm³⁺. The highest quantum yield among all the samples was 46.0% in the 0.3% Tm-doped sample. From pulse height spectra under ¹³⁷Cs γ-ray irradiation, the highest light yield among all the samples was estimated to be 510 photons/MeV in the 1% Tm-doped sample. According to afterglow curves, the afterglow was better than that of CsI:Tl.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112672"},"PeriodicalIF":2.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592413","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}

{"title":"Mn-doped ZnGa2O4 single crystals for dosimetry applications","authors":"Yuma Takebuchi ,&nbsp;Keitaro Tezuka ,&nbsp;Kensei Ichiba ,&nbsp;Takumi Kato ,&nbsp;Daisuke Nakauchi ,&nbsp;Noriaki Kawaguchi ,&nbsp;Takayuki Yanagida","doi":"10.1016/j.radphyschem.2025.112673","DOIUrl":"10.1016/j.radphyschem.2025.112673","url":null,"abstract":"<div><div>In this study, ZnGa₂O₄ single crystals were synthesized and the effects of Mn doping on their fundamental optical and dosimetric properties were investigated. The Mn-doped samples exhibited a luminescence peak caused by the 3d-3d transitions of Mn²⁺ in the photoluminescence (PL) and optically stimulated luminescence (OSL) processes. Mn doping increased the PL <em>QY</em>s despite a decrease in the number of trapping centers. The optimal Mn concentration for PL and OSL was determined to be 0.1%. The Mn-doped ZnGa₂O₄ single crystals showed better sensitivity than a commercial C-doped Al₂O₃ dosimeter for OSL dose-response functions.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112673"},"PeriodicalIF":2.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143583094","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}

{"title":"Towards complete decay spectroscopy of 152Tb","authors":"E.B. O’Sullivan ,&nbsp;S.M. Collins ,&nbsp;J.-M. Daugas ,&nbsp;L. Domenichetti ,&nbsp;J. Heery ,&nbsp;J. Henderson ,&nbsp;U. Köster ,&nbsp;C. Michelagnoli ,&nbsp;T. Parry ,&nbsp;S. Pascu ,&nbsp;P.H. Regan ,&nbsp;R. Shearman","doi":"10.1016/j.radphyschem.2025.112641","DOIUrl":"10.1016/j.radphyschem.2025.112641","url":null,"abstract":"<div><div>The radionuclide ¹⁵²Tb, decaying by <span><math><msup><mrow><mi>β</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span> emission and electron capture to ¹⁵²Gd with <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math></span> <span><math><mo>=</mo></math></span> 17.8784(95) h, has been shown in its first-in-human use to be suitable for positron emission tomography (PET) imaging. As a member of the terbium theragnostic quartet, this radionuclide has potential applications in personalised cancer treatments. Sources of ¹⁵²Tb were produced by proton-induced spallation of a tantalum target followed by on-line mass separation at CERN-ISOLDE. The sources were delivered to ILL Grenoble, where gamma–gamma coincidence spectroscopy of excited states populated in ¹⁵²Gd following the decay was carried out using the Fission Product Prompt <span><math><mi>γ</mi></math></span>-ray Spectrometer (FIPPS). Preliminary analysis has resulted in the identification of multiple previously unreported excited states in ¹⁵²Gd, thirteen of which are reported here at excitation energies up to 3746 keV. Angular correlation analysis has been used to provide initial spin and parity assignments to excited states. The result of the completed spectroscopy will be a revised gamma-ray and <span><math><msup><mrow><mi>β</mi></mrow><mrow><mo>+</mo></mrow></msup></math></span> dose to patients compared to the current expected values.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112641"},"PeriodicalIF":2.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production, analysis, and assessment of gamma-ray shielding performance of Gd2O3-Doped ZnO–B2O3 glasses using MCNP6 simulations","authors":"B. Buyuk ,&nbsp;O. Keskin ,&nbsp;Y. Karabul ,&nbsp;İ. Kocak ,&nbsp;M. Kamislioglu","doi":"10.1016/j.radphyschem.2025.112671","DOIUrl":"10.1016/j.radphyschem.2025.112671","url":null,"abstract":"<div><div>Advancing technology has expanded the use of ionizing radiation across various sectors, including medicine, energy, and defense. Given its potential risks to biological tissues, adhering to international radiation safety standards is crucial to safeguard workers' health and safety. In this study, innovative gamma radiation shielding glasses were developed using the composition (60-x)ZnO–30B₂O₃–10SiO₂-xGd₂O₃ (x = 0, 2.5, 5, 10, 20), where x varied from 0 to 20 mol%. The process involves melting, followed by quenching and subsequent annealing. Various proportions of Gd₂O₃ were incorporated into the ZnO, B₂O₃, and SiO₂ matrix as a sustainable alternative to lead shielding to mitigate the environmental impact of lead's toxic properties. Structural analysis, including XRD, was performed to validate the amorphous structure of the prepared glasses and confirm the incorporation of all components in the compositions following the melting process. The radiation shielding properties of the prepared glasses, such as mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), radiation protection efficiency, half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP), were assessed for gamma photons within the energy range of 0.356 MeV–1.33 MeV. The MAC values and HVL values of the glasses produced in this study are (0.075, 0.076, 0.077, 0.078, and 0.080) and (2.779, 2.549, 2.431, 2.203, and 1.883) respectively. Using Ba-133, Cs-137, and Co-60 point sources, measurements were conducted with NaI(Tl) scintillation detectors. The glasses' radiation response was examined through experimental and theoretical approaches. Furthermore, mass attenuation coefficients were validated against standard WinXCom data via MCNP6.2 simulations. Findings revealed that the glass containing 20% Gd₂O₃ exhibited the highest radiation shielding performance.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112671"},"PeriodicalIF":2.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143562588","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}

{"title":"Hydrogen generators in medical cyclotrons: A preliminary evaluation","authors":"Elena Miñana Olmo,&nbsp;Tomás Chivato Martín-Falquina","doi":"10.1016/j.radphyschem.2025.112668","DOIUrl":"10.1016/j.radphyschem.2025.112668","url":null,"abstract":"<div><div>Positron Emission Tomography (PET) has witnessed significant advances in radiopharmaceuticals and imaging technology, broadening its applications across oncology, neurology, and cardiology. PET radiopharmaceuticals are predominantly produced in cyclotrons. Hydrogen, a key element in cyclotron operation, is traditionally supplied via gas cylinders, posing challenges in purity, safety, and handling. This study evaluates the feasibility of using a hydrogen generator to supply high-purity hydrogen (grade 7.0) to a cyclotron's ion source (IS) for fluorine-18 production. A hydrogen generator was integrated with a PETtrace 880 cyclotron, and its performance was compared to conventional hydrogen cylinders across 34 irradiation runs of varying batch sizes. Results indicate that the test achieved consistent activity yields, stable hydrogen flow, and required lower arc current in the IS per unit of beam current, indicating higher efficiency. Additionally, the hydrogen generator offers safety benefits by minimizing high-pressure gas storage. While the device requires higher initial investment, its operational simplicity and potential to extend IS lifespan make it a viable alternative. Further studies are recommended to assess long-term impact and performance.</div></div>","PeriodicalId":20861,"journal":{"name":"Radiation Physics and Chemistry","volume":"232 ","pages":"Article 112668"},"PeriodicalIF":2.8,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580726","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}