Pub Date : 2024-10-23DOI: 10.1016/j.radmeas.2024.107322
Vo Hong Hai , Nguyen Quoc Hung , Nguyen Tri Toan Phuc , Masaharu Nomachi
This study investigates the contributions of various cosmic-ray-induced components to the energy response of a High-Purity Germanium (HPGe) gamma spectrometer within the 0°–45° zenith angle range. The analysis focuses on muons, neutrons, protons, electrons, positrons, and photons. It also examines the impact of particle showers induced by muons interacting with the lead chamber and reaching the HPGe detector. Utilizing the GEANT4 simulation toolkit, we provide a detailed examination of these components' influence on the spectrum. The results confirm that within this zenith angle range, muons account for approximately 91% of the recorded cosmic-ray induced energy spectrum and contribute 54.6% to the overall cosmic-ray-induced background spectrum. The study also highlights the significant role of showers, especially those resulting from muon interactions with the lead shielding, in shaping the low-energy spectrum below 3 MeV.
{"title":"Contributions of cosmic-ray components to the HPGe gamma spectrometer background spectrum within the 0°–45° Zenith angle range","authors":"Vo Hong Hai , Nguyen Quoc Hung , Nguyen Tri Toan Phuc , Masaharu Nomachi","doi":"10.1016/j.radmeas.2024.107322","DOIUrl":"10.1016/j.radmeas.2024.107322","url":null,"abstract":"<div><div>This study investigates the contributions of various cosmic-ray-induced components to the energy response of a High-Purity Germanium (HPGe) gamma spectrometer within the 0°–45° zenith angle range. The analysis focuses on muons, neutrons, protons, electrons, positrons, and photons. It also examines the impact of particle showers induced by muons interacting with the lead chamber and reaching the HPGe detector. Utilizing the GEANT4 simulation toolkit, we provide a detailed examination of these components' influence on the spectrum. The results confirm that within this zenith angle range, muons account for approximately 91% of the recorded cosmic-ray induced energy spectrum and contribute 54.6% to the overall cosmic-ray-induced background spectrum. The study also highlights the significant role of showers, especially those resulting from muon interactions with the lead shielding, in shaping the low-energy spectrum below 3 MeV.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"179 ","pages":"Article 107322"},"PeriodicalIF":1.6,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553431","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 : 2024-10-17DOI: 10.1016/j.radmeas.2024.107309
P.K. Witter , B. Champine , A.S. Tamashiro , P. Maggi
A Nuclear Accident Dosimetry program is a federal requirement for all facilities that have the potential to have a criticality accident. Personnel Nuclear Accident Dosimeter (PNAD) theory and analytical procedures are driven by various scientific needs and interacting regulations. A brief history of the status of USA Department of Energy (DOE) nuclear accident dosimetry regulations, recommendations, and performance testing criteria are given. Then, the history of the Lawrence Livermore National Laboratory (LLNL) PNAD is explored, including changes in the physical dosimeter and adjustments of the analysis method through the last four decades. Finally, the performance of LLNL’s PNAD at criticality accident intercomparison training exercises since 2009 is explored. In general, reported neutron doses have been within or close to DOE-STD-1098 performance criteria while reported gamma doses have been outside of DOE-STD-1098 performance criteria. Reported total absorbed doses have varied in meeting ANSI/HPS N13.3 and ANSI/HPS N13.3 (R2019) performance criteria. Dosimetry staff retirement and turnover have left historical knowledge gaps, yet provided opportunities within the NAD program at LLNL. This review paper serves as an overview of the history and status of the NAD program. Brief technical, procedural and programmatic recommendations to improve LLNL’s NAD program are given. Technical recommendations include investigating orientation factors through modeling or empirical experimentation, investigating gamma dosimetry methods for high-dose scenarios, and exploring other dosimetric methods for simpler, quicker NAD analysis. Procedural recommendations include better documentation of conversion factor (activity-to-fluence and fluence-to-dose) derivations and spectrum uses, and updated analysis spreadsheets or simple Graphic User Interfaces for dose calculations. Programmatic recommendations include formalized training for NAD analysts, and having multiple SMEs trained on the NAD program.
核事故剂量测定计划是联邦对所有可能发生临界事故的设施的要求。人员核事故剂量计 (PNAD) 理论和分析程序受各种科学需求和交互法规的驱动。本文简要介绍了美国能源部（DOE）核事故剂量测定法规、建议和性能测试标准的现状。然后，探讨了劳伦斯利弗莫尔国家实验室（LLNL）PNAD 的历史，包括过去四十年中物理剂量计的变化和分析方法的调整。最后，探讨了劳伦斯利弗莫尔国家实验室的 PNAD 自 2009 年以来在临界事故相互比对训练演习中的表现。总体而言，报告的中子剂量一直在 DOE-STD-1098 性能标准之内或接近该标准，而报告的伽马剂量一直在 DOE-STD-1098 性能标准之外。报告的总吸收剂量在满足 ANSI/HPS N13.3 和 ANSI/HPS N13.3 (R2019) 性能标准方面存在差异。剂量测定人员的退休和流动留下了历史性的知识空白，但也为 LLNL 的 NAD 计划提供了机会。本回顾文件概述了 NAD 计划的历史和现状。文中简要介绍了改进 LLNL NAD 计划的技术、程序和计划建议。技术建议包括通过建模或经验实验研究定向因素，研究高剂量情况下的伽马剂量测定方 法，以及探索其他剂量测定方法以进行更简单、更快速的 NAD 分析。程序方面的建议包括更好地记录转换系数（放射性活度-荧光和荧光-剂量）的推导和频谱用途，更新剂量计算的分析电子表格或简单的图形用户界面。程序方面的建议包括对 NAD 分析人员进行正式培训，以及让多个 SME 接受 NAD 程序方面的培训。
{"title":"A Review of the Lawrence Livermore Nuclear Accident Dosimeter 1980s-present","authors":"P.K. Witter , B. Champine , A.S. Tamashiro , P. Maggi","doi":"10.1016/j.radmeas.2024.107309","DOIUrl":"10.1016/j.radmeas.2024.107309","url":null,"abstract":"<div><div>A Nuclear Accident Dosimetry program is a federal requirement for all facilities that have the potential to have a criticality accident. Personnel Nuclear Accident Dosimeter (PNAD) theory and analytical procedures are driven by various scientific needs and interacting regulations. A brief history of the status of USA Department of Energy (DOE) nuclear accident dosimetry regulations, recommendations, and performance testing criteria are given. Then, the history of the Lawrence Livermore National Laboratory (LLNL) PNAD is explored, including changes in the physical dosimeter and adjustments of the analysis method through the last four decades. Finally, the performance of LLNL’s PNAD at criticality accident intercomparison training exercises since 2009 is explored. In general, reported neutron doses have been within or close to DOE-STD-1098 performance criteria while reported gamma doses have been outside of DOE-STD-1098 performance criteria. Reported total absorbed doses have varied in meeting ANSI/HPS N13.3 and ANSI/HPS N13.3 (R2019) performance criteria. Dosimetry staff retirement and turnover have left historical knowledge gaps, yet provided opportunities within the NAD program at LLNL. This review paper serves as an overview of the history and status of the NAD program. Brief technical, procedural and programmatic recommendations to improve LLNL’s NAD program are given. Technical recommendations include investigating orientation factors through modeling or empirical experimentation, investigating gamma dosimetry methods for high-dose scenarios, and exploring other dosimetric methods for simpler, quicker NAD analysis. Procedural recommendations include better documentation of conversion factor (activity-to-fluence and fluence-to-dose) derivations and spectrum uses, and updated analysis spreadsheets or simple Graphic User Interfaces for dose calculations. Programmatic recommendations include formalized training for NAD analysts, and having multiple SMEs trained on the NAD program.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"179 ","pages":"Article 107309"},"PeriodicalIF":1.6,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553432","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 : 2024-10-16DOI: 10.1016/j.radmeas.2024.107310
Lily Bossin , Riccardo Dal Bello , Jeppe Brage Christensen , Stefan Schischke , Silvia Motta , Michele Togno , Eduardo Gardenali Yukihara
This study aims to evaluate the performance of the BeO-based myOSLchip system (RadPro International GmbH, Remscheid, Germany) for dosimetry of proton and electron radiotherapy beams. Although beryllium oxide (BeO) has been recognised as a promising material for luminescence dosimetry in radiotherapy, this research extends beyond material properties and examines the entire BeO-based dosimetry system, including the detector, holder, and readout components.
Packages of myOSLchip dosimeters were irradiated either in a () MeV proton beam or in a 16 MeV electron beam. The readouts were carried out using the portable myOSLchip reader. In the electron beam, tests on the precision, dose response up to 100 Gy and dose-rate effects of the system were carried out. In the proton beam, the system was tested for its dose response (up to 10 Gy), fading, and linear energy transfer (LET) response.
For proton irradiations, the myOSLchip BeO OSLDs exhibited stability within 2% over 135 days, as well as a linear dose response in the tested range, () Gy. The efficiency showed a reduction for proton beams with LET values (for water) above 0.6 keV/m, with up to 40% loss in efficiency at 4 keV/m. For the electron irradiations, they showed a linear dose–response up to 20 Gy and dose-rate independence, with a constant response at least up to 2.99 × 105 Gy s−1. Using individual dosimeter sensitivity correction, the precision for a single dosimeter was around 3.5% (standard deviation of the data of all dosimeters) and for a package comprising four dosimeters was 1.7% (standard deviation of the mean of the four dosimeters).
These findings suggest the myOSLchip system’s potential as a reliable alternative to existing dosimetry systems in clinical applications.
{"title":"Performance of a BeO-based dosimetry system for proton and electron beam dose measurements","authors":"Lily Bossin , Riccardo Dal Bello , Jeppe Brage Christensen , Stefan Schischke , Silvia Motta , Michele Togno , Eduardo Gardenali Yukihara","doi":"10.1016/j.radmeas.2024.107310","DOIUrl":"10.1016/j.radmeas.2024.107310","url":null,"abstract":"<div><div>This study aims to evaluate the performance of the BeO-based myOSLchip system (RadPro International GmbH, Remscheid, Germany) for dosimetry of proton and electron radiotherapy beams. Although beryllium oxide (BeO) has been recognised as a promising material for luminescence dosimetry in radiotherapy, this research extends beyond material properties and examines the entire BeO-based dosimetry system, including the detector, holder, and readout components.</div><div>Packages of myOSLchip dosimeters were irradiated either in a (<span><math><mrow><mn>70</mn><mo>−</mo><mn>230</mn></mrow></math></span>) MeV proton beam or in a 16 MeV electron beam. The readouts were carried out using the portable myOSLchip reader. In the electron beam, tests on the precision, dose response up to 100 Gy and dose-rate effects of the system were carried out. In the proton beam, the system was tested for its dose response (up to 10 Gy), fading, and linear energy transfer (LET) response.</div><div>For proton irradiations, the myOSLchip BeO OSLDs exhibited stability within 2% over 135 days, as well as a linear dose response in the tested range, (<span><math><mrow><mn>0</mn><mo>.</mo><mn>1</mn><mo>−</mo><mn>10</mn></mrow></math></span>) Gy. The efficiency showed a reduction for proton beams with LET values (for water) above 0.6 keV/<span><math><mi>μ</mi></math></span>m, with up to 40% loss in efficiency at 4 keV/<span><math><mi>μ</mi></math></span>m. For the electron irradiations, they showed a linear dose–response up to 20 Gy and dose-rate independence, with a constant response at least up to 2.99 × 10<sup>5</sup> Gy s<sup>−1</sup>. Using individual dosimeter sensitivity correction, the precision for a single dosimeter was around 3.5% (standard deviation of the data of all dosimeters) and for a package comprising four dosimeters was 1.7% (standard deviation of the mean of the four dosimeters).</div><div>These findings suggest the myOSLchip system’s potential as a reliable alternative to existing dosimetry systems in clinical applications.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"179 ","pages":"Article 107310"},"PeriodicalIF":1.6,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526728","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}
Pub Date : 2024-10-16DOI: 10.1016/j.radmeas.2024.107320
Hiroki Kawamoto, Yutaka Fujimoto, Keisuke Asai
Radiophotoluminescence (RPL) is the phenomenon of emission from luminescence centers formed by ionizing radiation (RPL centers) and is applied in dosimeters. Knowledge regarding the development of RPL materials is limited and development of new RPL materials is required. In this study, we investigate the RPL properties of Au-doped soda-lime silicate glass. After X-ray irradiation, an emission band appeared at 650–900 nm upon excitation at 330 nm, and the emission intensity increased linearly in the dose range of 3.72–100 Gy. The UV–vis absorption, photoluminescence, and electron spin resonance spectroscopy revealed that the Au dimer, non-bridged oxygen hole center, and E’ center (electrons trapped in the glass host) were formed by ionizing radiation. The Au dimer acts as the RPL center. In addition, build-up, that is, progressive formation of RPL centers at room temperature, was completed in 20 min, and bleaching by 330 nm light was induced in Au-doped soda-lime silicate glass.
{"title":"Radiophotoluminescence from Au-doped soda-lime silicate glass","authors":"Hiroki Kawamoto, Yutaka Fujimoto, Keisuke Asai","doi":"10.1016/j.radmeas.2024.107320","DOIUrl":"10.1016/j.radmeas.2024.107320","url":null,"abstract":"<div><div>Radiophotoluminescence (RPL) is the phenomenon of emission from luminescence centers formed by ionizing radiation (RPL centers) and is applied in dosimeters. Knowledge regarding the development of RPL materials is limited and development of new RPL materials is required. In this study, we investigate the RPL properties of Au-doped soda-lime silicate glass. After X-ray irradiation, an emission band appeared at 650–900 nm upon excitation at 330 nm, and the emission intensity increased linearly in the dose range of 3.72–100 Gy. The UV–vis absorption, photoluminescence, and electron spin resonance spectroscopy revealed that the Au dimer, non-bridged oxygen hole center, and E’ center (electrons trapped in the glass host) were formed by ionizing radiation. The Au dimer acts as the RPL center. In addition, build-up, that is, progressive formation of RPL centers at room temperature, was completed in 20 min, and bleaching by 330 nm light was induced in Au-doped soda-lime silicate glass.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"179 ","pages":"Article 107320"},"PeriodicalIF":1.6,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526722","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}
Boron neutron capture therapy (BNCT) is a radiotherapy technology that selectively kills tumor cells via the 10B(n, α)7Li reactions. Epithermal neutrons (0.5 eV–10 keV) are emitted and converted into thermal neutrons, which have a larger neutron capture reaction cross-section, by slowing down in the human body before reaching the tumor. Recently, the development of an epithermal neutron absolute flux intensity measurement technique has become crucial for real-time in-vivo dose monitoring in BNCT. In this study, a concept for a measurement system consisting of multiple compact scintillator with optical fibers detectors covered with neutron absorbers of various thicknesses is proposed. The designed system achieves a consistent response to epithermal neutrons with a theoretical coefficient of variation not higher than 5% for both LiCAF and EJ-254 scintillators. The theoretical feasibility of the proposed measurement system was investigated by an irradiation experiment carried out at the heavy water neutron irradiation facility at the Kyoto University Reactor. The experimental results indicated that further improvement and refinement are necessary to meet the high accuracy and precision required for real-time dose monitoring in clinical applications.
{"title":"Preliminary study of a compact epithermal neutron absolute flux intensity measurement system for real-time in-vivo dose monitoring in boron neutron capture therapy","authors":"Jiye Qiu , Daisuke Hatano , Yulin Ge , Nikolaos Voulgaris , Kohei Sagara , Zhaopeng Qiao , Shingo Tamaki , Sachie Kusaka , Takushi Takata , Isao Murata","doi":"10.1016/j.radmeas.2024.107308","DOIUrl":"10.1016/j.radmeas.2024.107308","url":null,"abstract":"<div><div>Boron neutron capture therapy (BNCT) is a radiotherapy technology that selectively kills tumor cells via the <sup>10</sup>B(n, <em>α</em>)<sup>7</sup>Li reactions. Epithermal neutrons (0.5 eV–10 keV) are emitted and converted into thermal neutrons, which have a larger neutron capture reaction cross-section, by slowing down in the human body before reaching the tumor. Recently, the development of an epithermal neutron absolute flux intensity measurement technique has become crucial for real-time in-vivo dose monitoring in BNCT. In this study, a concept for a measurement system consisting of multiple compact scintillator with optical fibers detectors covered with neutron absorbers of various thicknesses is proposed. The designed system achieves a consistent response to epithermal neutrons with a theoretical coefficient of variation not higher than 5% for both LiCAF and EJ-254 scintillators. The theoretical feasibility of the proposed measurement system was investigated by an irradiation experiment carried out at the heavy water neutron irradiation facility at the Kyoto University Reactor. The experimental results indicated that further improvement and refinement are necessary to meet the high accuracy and precision required for real-time dose monitoring in clinical applications.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"178 ","pages":"Article 107308"},"PeriodicalIF":1.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142434395","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 : 2024-10-10DOI: 10.1016/j.radmeas.2024.107305
S. Motta, E.G. Yukihara
This work investigates theoretically possible dose rate effects in thermoluminescence (TL) and optically stimulated luminescence (OSL) materials by solving the rate equations for the stimulated luminescence process. Starting with the solution of the One-Trap–One-Recombination-Center (OTOR) model with parameters from the literature, we first showed that this model, with the chosen parameters, does not reproduce real luminescent material properties (e.g., TL curve and dose response). We then studied the physical phenomena responsible for dose rate effects in this model, and the influence of the model parameters on the dose rate response. As a result, we found that charge accumulation in the delocalized bands over unrealistic long periods ( hundreds of seconds) is responsible for dose rate effects. Such effect is caused by the particular choice of model parameters. When model parameters based on physical considerations and experimental results are chosen, no dose rate effects are observed. This work provides a deeper understanding of the luminescence process, by identifying the mechanisms that could be responsible for dose rate effects, and a theoretical foundation to the use of luminescent detectors for ultra-high dose rate dosimetry.
{"title":"Assessing dose rate effects in TL and OSL dosimeters: A critical look into dose rate models","authors":"S. Motta, E.G. Yukihara","doi":"10.1016/j.radmeas.2024.107305","DOIUrl":"10.1016/j.radmeas.2024.107305","url":null,"abstract":"<div><div>This work investigates theoretically possible dose rate effects in thermoluminescence (TL) and optically stimulated luminescence (OSL) materials by solving the rate equations for the stimulated luminescence process. Starting with the solution of the One-Trap–One-Recombination-Center (OTOR) model with parameters from the literature, we first showed that this model, with the chosen parameters, does not reproduce real luminescent material properties (e.g., TL curve and dose response). We then studied the physical phenomena responsible for dose rate effects in this model, and the influence of the model parameters on the dose rate response. As a result, we found that charge accumulation in the delocalized bands over unrealistic long periods (<span><math><mo>></mo></math></span> hundreds of seconds) is responsible for dose rate effects. Such effect is caused by the particular choice of model parameters. When model parameters based on physical considerations and experimental results are chosen, no dose rate effects are observed. This work provides a deeper understanding of the luminescence process, by identifying the mechanisms that could be responsible for dose rate effects, and a theoretical foundation to the use of luminescent detectors for ultra-high dose rate dosimetry.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"179 ","pages":"Article 107305"},"PeriodicalIF":1.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526726","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}
Pub Date : 2024-10-09DOI: 10.1016/j.radmeas.2024.107307
Jonathan Eakins , Michael Discher , Hyoungtaek Kim , Min Chae Kim , Hanjin Lee , Jungil Lee , Olivier Van Hoey , Hyungjoon Yu , Elizabeth Ainsbury , Céline Bassinet , Stephen McKeever , Sergey Sholom , Francois Trompier , Lovisa Waldner , Clemens Woda
Dose conversion coefficients attempt to harmonize the material-, location-, and exposure-dependent results from retrospective dosemeters. The issues and uncertainties arising from dose conversion are explored within the framework of an interlaboratory comparison exercise in which mobile phones were positioned around anthropomorphic phantoms and exposed to non-uniform photon fields, with the glass and resistors they contain employed as fortuitous dosemeters. The difficulties of adopting pre-calculated tables of generic conversion coefficients are evaluated first, and then compared against those arising through the use of bespoke data derived by Monte Carlo modelling, and also against not converting the doses measured by the phones. It is seen that the different subjective choices that users might make when selecting ‘optimal’ generic data can lead to a significant source of uncertainty (up to around 70 %), though may be improved (to around 30 %) by appropriate quality controls. Use of generic coefficients typically led to over-estimates of the organ doses: an average discrepancy of ca. a factor of 2 was found, but this is still better than the factor of around 3 observed when no conversion coefficients were applied. Use of bespoke conversion factors led to the best estimates of organ doses, although they still over-estimated by approximately 1.5 on average, and an uncertainty of around 20 % was associated with generating their values. Overall, applying bespoke conversion data improves but does not guarantee correct dose categorization of individuals, with the inconsistences in the measured results found generally to be the limiting factor in obtaining accurate dose assessments.
{"title":"Dose conversion in retrospective dosimetry: Results and implications from an inter-laboratory comparison featuring a realistic exposure scenario","authors":"Jonathan Eakins , Michael Discher , Hyoungtaek Kim , Min Chae Kim , Hanjin Lee , Jungil Lee , Olivier Van Hoey , Hyungjoon Yu , Elizabeth Ainsbury , Céline Bassinet , Stephen McKeever , Sergey Sholom , Francois Trompier , Lovisa Waldner , Clemens Woda","doi":"10.1016/j.radmeas.2024.107307","DOIUrl":"10.1016/j.radmeas.2024.107307","url":null,"abstract":"<div><div>Dose conversion coefficients attempt to harmonize the material-, location-, and exposure-dependent results from retrospective dosemeters. The issues and uncertainties arising from dose conversion are explored within the framework of an interlaboratory comparison exercise in which mobile phones were positioned around anthropomorphic phantoms and exposed to non-uniform photon fields, with the glass and resistors they contain employed as fortuitous dosemeters. The difficulties of adopting pre-calculated tables of generic conversion coefficients are evaluated first, and then compared against those arising through the use of bespoke data derived by Monte Carlo modelling, and also against not converting the doses measured by the phones. It is seen that the different subjective choices that users might make when selecting ‘optimal’ generic data can lead to a significant source of uncertainty (up to around 70 %), though may be improved (to around 30 %) by appropriate quality controls. Use of generic coefficients typically led to over-estimates of the organ doses: an average discrepancy of ca. a factor of 2 was found, but this is still better than the factor of around 3 observed when no conversion coefficients were applied. Use of bespoke conversion factors led to the best estimates of organ doses, although they still over-estimated by approximately 1.5 on average, and an uncertainty of around 20 % was associated with generating their values. Overall, applying bespoke conversion data improves but does not guarantee correct dose categorization of individuals, with the inconsistences in the measured results found generally to be the limiting factor in obtaining accurate dose assessments.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"179 ","pages":"Article 107307"},"PeriodicalIF":1.6,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142526727","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 : 2024-10-04DOI: 10.1016/j.radmeas.2024.107306
Chuanyi Wei , Gongming Yin , Yongsheng Zhou , Chunru Liu , Li Cheng , Xi Ma , Hao Ji , Jiaxiang Dang
The chronology of fault activity in bedrock is critical to constraining and understanding periods of active faulting, assessing seismic hazards, and mitigating the effects of earthquakes. However, because of the lack of suitable materials for dating, the temporal reconstruction of faulting in bedrock remains highly challenging for geologists. In the present study, we determine for the first time the electron spin resonance (ESR) ages of fault barite (BaSO4), which is produced by episodes of intense faulting on basalt bedrock fault surfaces. Three barite samples were obtained from a basalt fault section (27°5′23″N, 100°25′45″E, 1.8 km above sea level) of the Lijiang–Xiaojinhe Fault (LXF), southeastern Tibetan Plateau, for ESR measurements. Similar to marine barite, the ESR spectrum of fault barite shows an electron-type center with g = 2.0037, 2.0034, and 2.0028 attributed to SO3−. The signal intensity systematically increased with increasing gamma-ray dose. Dose rates were calculated using a model based on the location and burial depth of the barite samples, as well as their surrounding bedrock. The three barite samples yield ESR ages of 131 ± 26, 503 ± 61, and 1416 ± 246 ka, respectively, which indicate that the LXF was active during the Early and Middle Pleistocene. The three ESR ages for fault barite from basalt extend the time range of activity of the LXF compared with previous carbonate ESR and radiocarbon dating results. Consequently, we propose that ESR dating of barite is valuable for reconstructing the history of bedrock fault activity. However, given that this investigation represents a preliminary application of the fault-barite ESR method, further study is needed to confirm its usefulness and the accuracy and precision of dating results.
{"title":"Preliminary ESR dating results of fault barite shed new insights into the retrospective history of bedrock fault activities in basaltic regions","authors":"Chuanyi Wei , Gongming Yin , Yongsheng Zhou , Chunru Liu , Li Cheng , Xi Ma , Hao Ji , Jiaxiang Dang","doi":"10.1016/j.radmeas.2024.107306","DOIUrl":"10.1016/j.radmeas.2024.107306","url":null,"abstract":"<div><div>The chronology of fault activity in bedrock is critical to constraining and understanding periods of active faulting, assessing seismic hazards, and mitigating the effects of earthquakes. However, because of the lack of suitable materials for dating, the temporal reconstruction of faulting in bedrock remains highly challenging for geologists. In the present study, we determine for the first time the electron spin resonance (ESR) ages of fault barite (BaSO<sub>4</sub>), which is produced by episodes of intense faulting on basalt bedrock fault surfaces. Three barite samples were obtained from a basalt fault section (27°5′23″N, 100°25′45″E, 1.8 km above sea level) of the Lijiang–Xiaojinhe Fault (LXF), southeastern Tibetan Plateau, for ESR measurements. Similar to marine barite, the ESR spectrum of fault barite shows an electron-type center with g = 2.0037, 2.0034, and 2.0028 attributed to SO<sub>3</sub><sup>−</sup>. The signal intensity systematically increased with increasing gamma-ray dose. Dose rates were calculated using a model based on the location and burial depth of the barite samples, as well as their surrounding bedrock. The three barite samples yield ESR ages of 131 ± 26, 503 ± 61, and 1416 ± 246 ka, respectively, which indicate that the LXF was active during the Early and Middle Pleistocene. The three ESR ages for fault barite from basalt extend the time range of activity of the LXF compared with previous carbonate ESR and radiocarbon dating results. Consequently, we propose that ESR dating of barite is valuable for reconstructing the history of bedrock fault activity. However, given that this investigation represents a preliminary application of the fault-barite ESR method, further study is needed to confirm its usefulness and the accuracy and precision of dating results.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"178 ","pages":"Article 107306"},"PeriodicalIF":1.6,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420481","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 : 2024-09-27DOI: 10.1016/j.radmeas.2024.107303
Luana de Freitas Nascimento , Marijke De Saint-Hubert , Marco Caprioli , Laurence Delombaerde , Katleen Himschoot , Dirk Vandenbroucke , Paul Leblans , Wouter Crijns , Satoshi Kodaira
Real-time radioluminescence two-dimensional coatings have potential as dosemeters in proton and carbon therapeutic beams. We investigated coatings made of nano and micro-(C44H38P2)MnCl4 and (C38H36P2)MnBr4 crystals mixed with a water-equivalent substrate. The response of the radioluminescence signal of the coatings along the Bragg curves presented an ionization quenching effect, but less prominent than what has been observed in our previous works using Al2O3:X (X = C and C,Mg) coatings. We hypothesize that this results from their lower crystal sizes and effective atomic number (Zeff). Combined experimental results and Monte Carlo simulations resulted in correction factors to address the linear energy transfer dependence and restore the constant response for particle therapy beams. The quenching correction method was applied to the studied proton and carbon ion beams and yielded the best results for the nano-(C44H38P2)MnCl4, coating, followed by the micro-(C44H38P2)MnCl4, nano-(C38H36P2)MnBr4, and micro-(C38H36P2)MnBr4.
实时放射发光二维涂层具有作为质子和碳治疗束剂量计的潜力。我们研究了由纳米和微米-(C44H38P2)氯化锰和(C38H36P2)溴化锰晶体与水等效基质混合制成的涂层。涂层的辐射发光信号沿布拉格曲线的响应呈现出电离淬灭效应，但没有我们之前使用 Al2O3:X（X = C 和 C,Mg）涂层时观察到的效应那么突出。我们推测这是由于它们的晶体尺寸和有效原子序数（Zeff）较低造成的。结合实验结果和蒙特卡洛模拟，我们得出了修正系数，以解决线性能量转移依赖性问题，并恢复粒子治疗光束的恒定响应。淬火修正法适用于所研究的质子和碳离子束，对纳米（C44H38P2）氯化锰涂层的效果最好，其次是微量（C44H38P2）氯化锰、纳米（C38H36P2）溴化锰和微量（C38H36P2）溴化锰。
{"title":"Characterization of a real time dosimetry system using 2D nano and micro-coatings in proton and carbon therapeutic ion beams","authors":"Luana de Freitas Nascimento , Marijke De Saint-Hubert , Marco Caprioli , Laurence Delombaerde , Katleen Himschoot , Dirk Vandenbroucke , Paul Leblans , Wouter Crijns , Satoshi Kodaira","doi":"10.1016/j.radmeas.2024.107303","DOIUrl":"10.1016/j.radmeas.2024.107303","url":null,"abstract":"<div><div>Real-time radioluminescence two-dimensional coatings have potential as dosemeters in proton and carbon therapeutic beams. We investigated coatings made of nano and micro-(C<sub>44</sub>H<sub>38</sub>P<sub>2</sub>)MnCl<sub>4</sub> and (C<sub>38</sub>H<sub>36</sub>P<sub>2</sub>)MnBr<sub>4</sub> crystals mixed with a water-equivalent substrate. The response of the radioluminescence signal of the coatings along the Bragg curves presented an ionization quenching effect, but less prominent than what has been observed in our previous works using Al<sub>2</sub>O<sub>3</sub>:X (X = C and C,Mg) coatings. We hypothesize that this results from their lower crystal sizes and effective atomic number (Z<sub>eff</sub>). Combined experimental results and Monte Carlo simulations resulted in correction factors to address the linear energy transfer dependence and restore the constant response for particle therapy beams. The quenching correction method was applied to the studied proton and carbon ion beams and yielded the best results for the nano-(C<sub>44</sub>H<sub>38</sub>P<sub>2</sub>)MnCl<sub>4,</sub> coating, followed by the micro-(C<sub>44</sub>H<sub>38</sub>P<sub>2</sub>)MnCl<sub>4</sub>, nano-(C<sub>38</sub>H<sub>36</sub>P<sub>2</sub>)MnBr<sub>4</sub>, and micro-(C<sub>38</sub>H<sub>36</sub>P<sub>2</sub>)MnBr<sub>4</sub>.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"178 ","pages":"Article 107303"},"PeriodicalIF":1.6,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420480","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}
With the widespread application of nuclear technologies, radiation dose measurement is important. Ferrous sulfate dosimeters are common chemical dosimeters, but their high detection limit and narrow dosimetry range limit their application in some fields. In this work, we introduce a novel dosimetry approach for ferrous sulfate dosimeters utilizing the fluorescence properties of gold nanoclusters (AuNCs) capped with histidine. The Fe2+ ions in the ferrous sulfate dosimeter are oxidized to Fe3+ ions during irradiation. The presence of Fe3+ ions results in the fluorescence quenching of AuNCs, establishing a correlation between the fluorescence intensity of the dosimeter and irradiation doses. The lowest detection limit of the fluorescence dosimeter was found to be 2 Gy. Moreover, the dose response of the dosimeter showed good linearity within the dose range of 2–400 Gy. The dosimetric sensitivity of the fluorescence dosimeter was 17.9% higher than that of ultraviolet–visible spectroscopy. The results indicate that the dosimetry method utilizing the fluorescence properties of AuNCs significantly improves the detection sensitivity and detection limit of the dosimeter. Our work provides a new dosimetry method for ferrous sulfate dosimeters that can be used in a wider range of irradiation situations.
{"title":"High-sensitivity ferrous sulfate dosimeters with wide dosimetry range based on fluorescence properties of gold nanoclusters","authors":"Yu Chen, Shuquan Chang, Xiaodan Hu, Xiaohong Zhang, Haiqian Zhang","doi":"10.1016/j.radmeas.2024.107304","DOIUrl":"10.1016/j.radmeas.2024.107304","url":null,"abstract":"<div><div>With the widespread application of nuclear technologies, radiation dose measurement is important. Ferrous sulfate dosimeters are common chemical dosimeters, but their high detection limit and narrow dosimetry range limit their application in some fields. In this work, we introduce a novel dosimetry approach for ferrous sulfate dosimeters utilizing the fluorescence properties of gold nanoclusters (AuNCs) capped with histidine. The Fe<sup>2+</sup> ions in the ferrous sulfate dosimeter are oxidized to Fe<sup>3+</sup> ions during irradiation. The presence of Fe<sup>3+</sup> ions results in the fluorescence quenching of AuNCs, establishing a correlation between the fluorescence intensity of the dosimeter and irradiation doses. The lowest detection limit of the fluorescence dosimeter was found to be 2 Gy. Moreover, the dose response of the dosimeter showed good linearity within the dose range of 2–400 Gy. The dosimetric sensitivity of the fluorescence dosimeter was 17.9% higher than that of ultraviolet–visible spectroscopy. The results indicate that the dosimetry method utilizing the fluorescence properties of AuNCs significantly improves the detection sensitivity and detection limit of the dosimeter. Our work provides a new dosimetry method for ferrous sulfate dosimeters that can be used in a wider range of irradiation situations.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"178 ","pages":"Article 107304"},"PeriodicalIF":1.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357306","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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