Applied Radiation and Isotopes最新文献

{"title":"Luminescence enhancement and thermal stability of alkali co-doped Eu³⁺:LaMgB₅O₁₀ phosphors.","authors":"V Onar, E Ekdal Karali, Abeer S Altowyan, H Aydin, U H Kaynar, C Gök, M B Coban, Jabir Hakami, Y Ozcan, A Canimoglu, N Can","doi":"10.1016/j.apradiso.2025.112219","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112219","url":null,"abstract":"<p><p>Eu³⁺-activated LaMgB₅O₁₀ (LMBO:Eu³⁺) phosphors were synthesized and systematically investigated to elucidate the role of alkali co-doping (Li⁺, K⁺) on their structural and luminescence properties. XRD, Raman, and FTIR analyses confirmed the phase purity and revealed subtle lattice distortions upon alkali incorporation, while SEM/EDS verified homogeneous dopant distribution. Photoluminescence spectra are dominated by the characteristic ⁵D₀→⁷FJ transitions of Eu³⁺, with alkali ions inducing pronounced modifications in band distribution and emission intensity. Li⁺ co-doping yields a moderate enhancement and redistributes oscillator strength toward the ⁵D₀→⁷F₄ transition, whereas K⁺ co-doping produces nearly an order of magnitude increase in far-red emission. Judd-Ofelt analysis provided intensity parameters (Ω₂, Ω₄, Ω₆), radiative lifetimes, and quantum efficiencies, highlighting the impact of alkali-induced site symmetry perturbations. Temperature-dependent PL measurements revealed distinct quenching and anti-thermal quenching (ATQ) behaviors: undoped Eu³⁺ exhibited conventional quenching with an activation energy of 0.404 eV, K⁺ co-doping reduced the barrier to 0.205 eV and triggered moderate ATQ above 470 K, while Li⁺ co-doping produced strong ATQ with emission intensity increasing nearly fourfold at 550 K. These findings demonstrate that alkali co-doping not only enhances far-red emission at room temperature but also stabilizes or even amplifies luminescence at elevated temperatures, making LMBO:Eu³⁺,M⁺ phosphors promising candidates for high-power pc-WLEDs and plant-growth lighting.</p>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"112219"},"PeriodicalIF":1.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145211526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Production of [¹⁸F]NAV4694 on an FX2N synthesis module for imaging amyloid plaques.","authors":"Pardeep Kumar, Sandhya Mangalore, Raman Kumar Joshi, Venkatesh Murthy, Aishwarya Kumar, Keerti Sitani, Anupama Vajjala, Yashwanth Gurushanthappa, Deeksha Muralidharan, Manoj Kumar, Palanimuthu T Sivakumar","doi":"10.1016/j.apradiso.2025.112216","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112216","url":null,"abstract":"<p><strong>Introduction: </strong>Amyloid PET imaging has changed the management of Alzheimer's disease patients. Several radiopharmaceuticals have evolved in the last two decades. We are reporting the synthesis of the amyloid imaging PET tracer fluorine-18[¹⁸F]NAV4694 in the FX2N synthesis module under GMP-compliant conditions for clinical use.</p><p><strong>Methods: </strong>The radiosynthesis was standardised in the FX2N synthesis module, and the precursor concentration was varied from 0.5 to 2.0 mg for labelling with ¹⁸F at 110 °C, with a reaction time of 5-10 min, followed by hydrolysis with 0.6 M HCl for 5 min. The final purification was standardised with various C18 cartridges to get the maximum yield. All standard quality controls were performed, along with in vivo stability. Briefly, 350 ± 50 MBq of the [¹⁸F]NAV4694 was injected intravenously in patients, and PET-MR imaging was performed. The images were processed, and the distribution of the tracer was visually observed in the brain.</p><p><strong>Results: </strong>A minimum of 2 mg concentration was found to be suitable for radiolabeling at 110 °C for 10 min and purified via C18 plus long cartridge, providing the highest radiochemical yield of 13 ± 3 % (decay corrected). The radiochemical purity was 99 ± 0.5 % with a molar activity of 255 ± 125 GBq/μmol. The retention time of the [¹⁸F]NAV4694 was 17.6 ± 0.8 min, which was consistent with the UV/Vis peak of cold NAV4694 at 17.4 ± 0.7 min. The residual solvents, like DMSO and ethanol, were less than the prescribed limit. The HPLC (from plasma) showed no primary metabolites in the plasma, and the stability was 96 ± 2 % (in vitro) and 94 ± 2 % (in vivo). The human biodistribution showed a rapid clearance from the blood. The visual analysis showed uptake in cortical grey matter in a positive amyloid scan and in white matter in an amyloid-negative scan.</p><p><strong>Conclusion: </strong>[¹⁸F]NAV4694 was successfully synthesised in the FX2N synthesis module with high radiochemical purity. It showed distinctive uptake patterns in amyloid-positive and negative scans.</p>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"112216"},"PeriodicalIF":1.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145211482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of a novel, large volume CdZnTe detector for marine applications.","authors":"Georgios Siltzovalis, Varvara Lagaki, Ioannis Madesis, Theo J Mertzimekis","doi":"10.1016/j.apradiso.2025.112206","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112206","url":null,"abstract":"<p><p>A large-volume (4 cm³) monolithic CdZnTe detector was selected for a novel underwater γ-radiation sensing instrument for radioactivity measurements near the seabed. The focus of this paper was to characterize the detector to adapt to the challenges expected during underwater operation. Initially, its efficiency and energy resolution were determined experimentally. Then, two underwater laboratory experiments were utilized. The first compared the detector efficiency from measurements performed in the air and then underwater. A decrease in efficiency was observed for low energy γ-rays during the underwater measurement. The second experiment evaluated the sensitivity of the method in underwater detection of ⁴⁰K. The results revealed the limitations of the detector in real-life measurement scenarios. Next, Monte Carlo simulations were performed, focusing on the marinization of the detector. Candidate materials were investigated for the manufacturing of the necessary underwater housing. From the analysis of the results and considering real-world challenges expected in the marine environment, an aluminum housing was found to be optimal for the instrument development. Finally, the most efficient placement of the instrument with regard to the surface of the seabed was determined considering the detection range and the efficiency of the setup. It was concluded that a horizontal placement was the most suitable one. The proposed CdZnTe instrument is expected to provide a novel solution for underwater radioactivity studies in deep ocean environments and operation under harsh conditions. The main advantages it can offer are: the good energy resolution and efficiency, which are necessary for efficient underwater radioactivity monitoring.</p>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"112206"},"PeriodicalIF":1.8,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Luminescent properties of perovskite type GdAlO3: Dy3+ obtained by co-precipitation method","authors":"D. Nolasco-Altamirano ,&nbsp;A. Alonso-Sotolongo ,&nbsp;O.A. García-Garduño ,&nbsp;J. Zarate-Medina ,&nbsp;S.Y. Vicencio-Hernández ,&nbsp;I. Garduño-Wilches ,&nbsp;T. Rivera-Montalvo","doi":"10.1016/j.apradiso.2025.112220","DOIUrl":"10.1016/j.apradiso.2025.112220","url":null,"abstract":"<div><div>In the present work synthesis and luminescent properties of gadolinium aluminate doped with activator of trivalent ion Dy³⁺ was successful achieved through the coprecipitation method. Powder X-ray diffraction (XRD) technique was employed to identify phase purity on the crystallographic structure. The luminescent properties were investigated using photoluminescence (PL), and thermoluminescence (TL) measurements. Experimental PL measurements revealed that the intensity of luminescence emission was observed with respect to the energy transfer processes between the host and the Dy³⁺. The dependence of thermoluminescence intensity of dopant concentration was investigated with varied depending on the concentration of Dy³⁺ ions. TL measurements were conducted between room temperature (RT) and 350 °C at a heating rate of 10 °C/s. A significant TL glow curve was observed consisting with two peaks centered at 150 and 260 °C under different β-dose exposures. TL response of the powders displayed good linearity in the range of 0.5–44 Gy. Currently findings confirm that gadolinium aluminate as host is a promising candidate for beta radiation studies because exhibits adequate TL dose response with a good sensitivity and linearity for beta radiation application.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"Article 112220"},"PeriodicalIF":1.8,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145205452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of local diagnostic reference levels for adult chest CT examinations at a South African tertiary hospital in Gauteng province, South Africa.","authors":"Mpumelelo Nyathi","doi":"10.1016/j.apradiso.2025.112207","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112207","url":null,"abstract":"<p><strong>Introduction: </strong>Computed tomography (CT) provides high-resolution three-dimensional images. However, there are concerns that CT delivers high patient doses. To mitigate risks, the International Commission on Radiological Protection introduced Diagnostic Reference Levels (DRLs) aimed at optimization of doses while maintaining acceptable image quality. This study established local DRLs for adult chest CT scans using dose length product (DLP) and volumetric CT dose index (CTDI_vol) doses at a tertiary hospital.</p><p><strong>Materials and methods: </strong>A retrospective review of CTDI_vol and DLP values for 50 patients (≥18 years, weighing 70 ± 10 kg) who underwent non-contrast chest CT examinations. CT scan parameters were also documented. Median CTDI_vol and DLP doses were calculated as local DRLs, while the 75th percentile values were proposed as national DRLs for benchmarking with international studies. Independent samples t-test compared dose metrics between male and female patients. Statistical significance was set at p < 0.05.</p><p><strong>Results: </strong>The median CTDI_vol values were 9.5 mGy and 10.8 mGy for females and males respectively (p = 0.18) while respective median DLP values were 370.8 mGy cm and 447.6 mGy cm (p = 0.02). The established local DRLs in terms of CTDI_vol and DLP were 10.4 mGy and 428.9 mGy cm respectively while the respective proposed national DRLs were 14.4 mGy and 622.2 mGy cm. CTDI_vol values were comparable to international DRLs while DLP values were higher.</p><p><strong>Conclusion: </strong>The established local DRLs provide a baseline for optimizing adult chest CT practices at our institution and a first step toward establishment of national DRL standards in South Africa.</p>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"112207"},"PeriodicalIF":1.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to \"Effect of gamma radiation on optical properties of PVA/PEG/EY blend, and radiochromism\" [Appl. Radiat. Isotopes 225 (2025) 112050].","authors":"Yamen A Alibwaini, O M Hemeda, Marwan S Mousa, T Sharshar, Enas A Arrasheed, Abdul-Wali Ajlouni, A H Ashour, R ElShater, Magda Elsehly, Ilya A Weinstein, A M A Henaish","doi":"10.1016/j.apradiso.2025.112199","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112199","url":null,"abstract":"","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":" ","pages":"112199"},"PeriodicalIF":1.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of natural radionuclides in NORM - inter-comparison exercise in the Czech Republic.","authors":"Alena Kelnarová, Tereza Doksanská, Lenka Dragounová","doi":"10.1016/j.apradiso.2025.112208","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112208","url":null,"abstract":"","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"112208"},"PeriodicalIF":1.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145228380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study on the production method of thin films for low-energy beta measurement","authors":"Y.J. Park,&nbsp;D.H. Heo,&nbsp;T.H. Kim,&nbsp;K.B. Lee,&nbsp;J.M. Lee,&nbsp;B.C. Kim","doi":"10.1016/j.apradiso.2025.112214","DOIUrl":"10.1016/j.apradiso.2025.112214","url":null,"abstract":"<div><div>The primary standard for coincidence counting of 4πβ(PPC)-γ requires thin films that minimize the attenuation of beta particles. In this study, we developed a method to control the thickness of these films. Traditional methods for producing thin films often resulted in wrinkles over time; however, our newly developed approaches allow for the production of wrinkle-free thin films with adjustable thickness. We designed specialized equipment for thin film production and analyzed the relationship between solution volume and resulting film thickness. Films were produced using a mixture of collodion and isopentyl acetate with volumes ranging from 20 μL to 80 μL, resulting in thicknesses from approximately 40 nm–160 nm. The effect of film thickness on low-energy radiation was experimentally analyzed using ⁵⁹Ni sources and compared with Monte Carlo simulations. Results confirm that film thickness significantly affects the measurement of low-energy electrons like Auger electrons, while having minimal impact on X-rays of similar energy.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"Article 112214"},"PeriodicalIF":1.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145205487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of emission intensity for low energy photons following the decay of ¹⁰⁹Cd.","authors":"Aurelian Luca, Andrei Antohe, Ioana Lalău, George Paţă","doi":"10.1016/j.apradiso.2025.112210","DOIUrl":"https://doi.org/10.1016/j.apradiso.2025.112210","url":null,"abstract":"<p><p>Following the participation to the CCRI(II)-K2.Cd-109 international comparison, accurate activity standardization of a¹⁰⁹Cd radioactive solution was performed at IFIN-HH/Ionising Radiation Metrology Laboratory. Based on these results, measurements of the emission intensity for low energy photons (gamma- and X-rays) following the decay of ¹⁰⁹Cd were undertaken: γ-rays of 88.03 keV and K_α and K_β X-rays (¹⁰⁹Ag). For this purpose, two spectrometry systems, based on HPGe and Si(Li) detectors, were used. The calibration of the spectrometers was performed by combining the measurement of radioactive standard sources to a detection efficiency transfer procedure by Monte Carlo simulation with the GESPECOR software. The results obtained, including the uncertainty budgets, are provided and compared to other data sets published in the literature. These new data will be useful for future ¹⁰⁹Cd nuclear data evaluations.</p>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"112210"},"PeriodicalIF":1.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145243581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the techniques for primary calibration of electronic radon detectors","authors":"K. Mitev ,&nbsp;B. Sabot ,&nbsp;V. Todorov ,&nbsp;S. Georgiev ,&nbsp;S. Pierre ,&nbsp;S. Röttger ,&nbsp;B. Krastev ,&nbsp;I. Dimitrova","doi":"10.1016/j.apradiso.2025.112209","DOIUrl":"10.1016/j.apradiso.2025.112209","url":null,"abstract":"<div><div>Successful calibration of RadonEye +2 electronic radon detectors was performed at typical indoor activity concentrations using the facilities at LNHB and PTB. The calibration uncertainties using primary radon activity standards were: below 1.5 % at 300 Bq/m³, below 1.7 % at 130 Bq/m³ and below 2.5 % at 55 Bq/m³ (<em>k</em> = 1). When using the secondary standard AlphaGUARD, the uncertainty at 55 Bq/m³ was below 3.5 %. Maintaining stable activity concentrations proved crucial and appears to be the only feasible approach for calibrations below 100 Bq/m³. While calibration under exponentially decaying radon activity concentration remains useful for evaluating the devices’ linearity across a broad range, it proved unsuitable for calibration of user-grade monitors at low activities due to the high statistical variation in their signal.</div><div>The linearity of RadonEye +2 was demonstrated in the range 50 Bq/m³ - 300 Bq/m³ and they will be utilized for the sensor networks developed within the RadonNET project. Dynamic background correction, applicable to non-spectrometric detectors, was applied based on the monitor's exposure history. Furthermore, it was observed that the pulse-processing algorithm of RadonEyes +2 distorts the Poisson distribution of the signal, thereby increasing its variation. Potentially, lower measurement uncertainty could be achieved with electronic radon detectors that report the registered pulses and allow access to their processing algorithms.</div></div>","PeriodicalId":8096,"journal":{"name":"Applied Radiation and Isotopes","volume":"226 ","pages":"Article 112209"},"PeriodicalIF":1.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}