Pub Date : 2026-02-01Epub Date: 2025-11-28DOI: 10.1016/j.radmeas.2025.107566
Jacob C. Warming, Peter Balling, Rosana M. Turtos
Long-lived defect states in large-band-gap materials can potentially store energy from ionising radiation allowing the materials to be used as dosimeters. The population in many of these dosimetric traps can be read out with optically stimulated luminescence (OSL). OSL is associated with a cross section for the excitation probability, and the wavelength dependence of the cross section provides insight into the physical characteristics of the traps and allows for an optimised readout of OSL-dosimeters.
This paper suggests a novel approach to measuring the optical cross section using a pulsed tunable laser. A model of the evolution of the trap population is used to analyse data taken pulse-by-pulse to determine the cross sections in YSiO5:Ce. The cross sections are compared to theoretical models in order to determine the trap depth and phonon contribution. The wavelength-dependent cross section increases monotonically as the wavelength decreases, varying by more than two orders of magnitude from at the longest wavelengths (800 nm) to more than m in the green and blue part of the spectrum. Depending on the theoretical model used, the main trap depth is within the range 2.1–2.6 eV with a characteristic value of 2.3 eV, aligning with published results. Additionally, a notable phonon contribution is found with a magnitude that is consistent with previously reported phonon energies.
{"title":"Wavelength-dependent cross section for optically stimulated luminescence in Y2SiO5:Ce","authors":"Jacob C. Warming, Peter Balling, Rosana M. Turtos","doi":"10.1016/j.radmeas.2025.107566","DOIUrl":"10.1016/j.radmeas.2025.107566","url":null,"abstract":"<div><div>Long-lived defect states in large-band-gap materials can potentially store energy from ionising radiation allowing the materials to be used as dosimeters. The population in many of these dosimetric traps can be read out with optically stimulated luminescence (OSL). OSL is associated with a cross section for the excitation probability, and the wavelength dependence of the cross section provides insight into the physical characteristics of the traps and allows for an optimised readout of OSL-dosimeters.</div><div>This paper suggests a novel approach to measuring the optical cross section using a pulsed tunable laser. A model of the evolution of the trap population is used to analyse data taken pulse-by-pulse to determine the cross sections in Y<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>SiO<sub>5</sub>:Ce. The cross sections are compared to theoretical models in order to determine the trap depth and phonon contribution. The wavelength-dependent cross section increases monotonically as the wavelength decreases, varying by more than two orders of magnitude from <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>24</mn></mrow></msup></mrow></math></span> at the longest wavelengths (800 nm) to more than <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>22</mn></mrow></msup></mrow></math></span> m<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span> in the green and blue part of the spectrum. Depending on the theoretical model used, the main trap depth is within the range 2.1–2.6 eV with a characteristic value of 2.3 eV, aligning with published results. Additionally, a notable phonon contribution is found with a magnitude that is consistent with previously reported phonon energies.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107566"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683168","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 : 2026-02-01Epub Date: 2025-11-22DOI: 10.1016/j.radmeas.2025.107567
Owen M. Williams, Nigel A. Spooner
We critically examine the quartz defect pair model, within which physical explanations of quartz thermoluminescence and optically stimulated luminescence (OSL) were introduced. We address the apparent circularity of the model, in that it appears to lack an appropriate OSL terminal reaction. In particular, by appropriately analysing prior spectral OSL measurements, we demonstrate that the prominent primary peak centred at 365 nm is accompanied by a smaller secondary peak. With this insight, we proceed to extend the existing defect pair model by introducing a new OSL reaction pair which not only takes account of the secondary peak but also offsets the source of the circularity. We complete our study by introducing a configurational coordinate diagram that includes a new terminating antibonding state, the presence of which is consistent with both the measurement data and our defect pair model extension.
{"title":"Offsetting circularity within an extended quartz luminescence defect pair model","authors":"Owen M. Williams, Nigel A. Spooner","doi":"10.1016/j.radmeas.2025.107567","DOIUrl":"10.1016/j.radmeas.2025.107567","url":null,"abstract":"<div><div>We critically examine the quartz defect pair model, within which physical explanations of quartz thermoluminescence and optically stimulated luminescence (OSL) were introduced. We address the apparent circularity of the model, in that it appears to lack an appropriate OSL terminal reaction. In particular, by appropriately analysing prior spectral OSL measurements, we demonstrate that the prominent primary peak centred at 365 nm is accompanied by a smaller secondary peak. With this insight, we proceed to extend the existing defect pair model by introducing a new OSL reaction pair which not only takes account of the secondary peak but also offsets the source of the circularity. We complete our study by introducing a configurational coordinate diagram that includes a new terminating antibonding state, the presence of which is consistent with both the measurement data and our defect pair model extension.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107567"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683167","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 : 2026-02-01Epub Date: 2025-12-03DOI: 10.1016/j.radmeas.2025.107583
Xinyu Yang , Jian Yang , Guoqiang Zeng , Haowen Deng , Chengshuai Tian , Chuanhao Hu
For radioactive source localization, traditional Compton cameras are limited by the imaging field-of-view (FOV) and low detection efficiency, resulting in slow response in complex environments. To address the limitations in the azimuthal sensitivity of conventional dual-layer scintillator detectors and the sensitive volume of semiconductor detectors, this study proposes an omnidirectional Compton camera based on four-sided scintillator detectors with a square ring-shaped structure. This imaging system features omnidirectional sensitivity with a continuous 360° azimuthal response, significantly enhancing detection efficiency by minimizing the escape of scattered photons. The smallest imaging unit utilizes an independent CsI(Tl) crystal coupled with a single SiPM, which reduces light propagation loss and improves light collection efficiency to enhance energy resolution. To simplify the electronic systems, a serial readout circuit is employed to reduce the readout channels. The experimental results demonstrate that the total energy resolution for the 137Cs source was 6.2 % (FWHM) after calibrating the position and energy. Using the maximum likelihood expectation maximization algorithm for image reconstruction, the imaging system achieves accurate localization of radioactive sources with an angular resolution of 12° and clearly distinguishes the position of two radioactive sources.
{"title":"Development of an omnidirectional Compton camera with enhanced energy resolution for radioactive source localization","authors":"Xinyu Yang , Jian Yang , Guoqiang Zeng , Haowen Deng , Chengshuai Tian , Chuanhao Hu","doi":"10.1016/j.radmeas.2025.107583","DOIUrl":"10.1016/j.radmeas.2025.107583","url":null,"abstract":"<div><div>For radioactive source localization, traditional Compton cameras are limited by the imaging field-of-view (FOV) and low detection efficiency, resulting in slow response in complex environments. To address the limitations in the azimuthal sensitivity of conventional dual-layer scintillator detectors and the sensitive volume of semiconductor detectors, this study proposes an omnidirectional Compton camera based on four-sided scintillator detectors with a square ring-shaped structure. This imaging system features omnidirectional sensitivity with a continuous 360° azimuthal response, significantly enhancing detection efficiency by minimizing the escape of scattered photons. The smallest imaging unit utilizes an independent CsI(Tl) crystal coupled with a single SiPM, which reduces light propagation loss and improves light collection efficiency to enhance energy resolution. To simplify the electronic systems, a serial readout circuit is employed to reduce the readout channels. The experimental results demonstrate that the total energy resolution for the <sup>137</sup>Cs source was 6.2 % (FWHM) after calibrating the position and energy. Using the maximum likelihood expectation maximization algorithm for image reconstruction, the imaging system achieves accurate localization of radioactive sources with an angular resolution of 12° and clearly distinguishes the position of two radioactive sources.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107583"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683165","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 : 2026-02-01Epub Date: 2025-12-08DOI: 10.1016/j.radmeas.2025.107588
Clemens Woda , Michael Discher
Emergency dosimetry using mobile phone components has become an increasingly interesting field for post-accident dose assessment. This study investigates the TL and OSL emission properties of alumina substrates from resistors and inductors found in mobile phone circuit boards, with a focus on the dosimetric potential of the red Cr3+-related TL emission. Spectral measurements reveal three primary emission bands around 330 nm and 410 nm, attributable to F+ and F centers respectively, and a dominant emission at 695 nm, characteristic of Cr3+. In TL, the Cr3+ emission clearly dominates, particularly in resistors, with intensity exceeding that of the blue/UV emissions by up to two orders of magnitude. The red TL signal exhibits a linear dose response over a wide range (from mGy to >10 Gy), low intrinsic background, and fading characteristics consistent with anomalous fading (∼20.7 %/decade). Dose recovery experiments immediately after irradiation confirm accuracy within 7 %, a minor dose overestimation caused by minor desensitization. The red TL signal is optically bleachable, similar to its blue/UV counterpart. Irradiation trials with intact smartphones demonstrated that the red TL method delivers dose estimates within 25 % of the reference dose, comparable to established methods using display glass or OSL on resistors. Importantly, dose estimation using only a single resistor achieved similar sensitivity to protocols requiring ten components in the blue/UV range. These results highlight the potential of red TL for accurate, sensitive, and minimally invasive retrospective dosimetry. The method offers distinct advantages in scenarios where only few components are available and enables the prospect of non-destructive measurements.
{"title":"TL/OSL emission spectrometry of alumina substrates of electronic components in mobile phones: potential of the red TL emission for retrospective dosimetry","authors":"Clemens Woda , Michael Discher","doi":"10.1016/j.radmeas.2025.107588","DOIUrl":"10.1016/j.radmeas.2025.107588","url":null,"abstract":"<div><div>Emergency dosimetry using mobile phone components has become an increasingly interesting field for post-accident dose assessment. This study investigates the TL and OSL emission properties of alumina substrates from resistors and inductors found in mobile phone circuit boards, with a focus on the dosimetric potential of the red Cr<sup>3+</sup>-related TL emission. Spectral measurements reveal three primary emission bands around 330 nm and 410 nm, attributable to F<sup>+</sup> and F centers respectively, and a dominant emission at 695 nm, characteristic of Cr<sup>3+</sup>. In TL, the Cr<sup>3+</sup> emission clearly dominates, particularly in resistors, with intensity exceeding that of the blue/UV emissions by up to two orders of magnitude. The red TL signal exhibits a linear dose response over a wide range (from mGy to >10 Gy), low intrinsic background, and fading characteristics consistent with anomalous fading (∼20.7 %/decade). Dose recovery experiments immediately after irradiation confirm accuracy within 7 %, a minor dose overestimation caused by minor desensitization. The red TL signal is optically bleachable, similar to its blue/UV counterpart. Irradiation trials with intact smartphones demonstrated that the red TL method delivers dose estimates within 25 % of the reference dose, comparable to established methods using display glass or OSL on resistors. Importantly, dose estimation using only a single resistor achieved similar sensitivity to protocols requiring ten components in the blue/UV range. These results highlight the potential of red TL for accurate, sensitive, and minimally invasive retrospective dosimetry. The method offers distinct advantages in scenarios where only few components are available and enables the prospect of non-destructive measurements.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107588"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790522","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 : 2026-02-01Epub Date: 2025-11-28DOI: 10.1016/j.radmeas.2025.107570
T. Genetay , L. Tlustos , M. Campbell , F. Bochud , P. Carbonez , J. Damet
This work presents, to the best of the authors’ knowledge, the first attempt at reconstructing X-ray spectra with a hybrid pixel detector for radiation protection applications in the scattered field around fluoroscopy devices. The performance of the Timepix4 detector was evaluated under reference conditions using RQR beam qualities. A dedicated methodology was developed to correct for detection efficiency, explicitly accounting for contributions from Compton scattering and the photoelectric effect. Accuracy was assessed through Monte Carlo simulations and comparisons with published RQR reference spectra. In addition, particle fluence measurements obtained with Timepix4 were validated against values derived from kerma factors and ionisation chamber measurements performed in a calibration laboratory. The results show excellent agreement between reconstructed and reference spectra up to , with residuals below 1.7% and relative photon fluence shifts within 5%. At higher energies, discrepancies increase due to the low detection efficiency of the silicon sensor, requiring large correction factors and leading to greater statistical fluctuations. Nevertheless, the system demonstrated acceptable performance up to , with fluence shifts remaining below 16%. Linearity was confirmed across all beam qualities and intensities investigated, consistent with previous studies on earlier Timepix ASIC generations. Overall, these findings demonstrate that Timepix4 can provide reliable spectral and fluence measurements in reference X-ray beams, offering valuable information for radiation protection studies in scattered fields where conventional detectors are of limited use. Future improvements in readout bandwidth and spectral deconvolution methods are expected to extend its applicability to higher energies and clinical environments.
{"title":"RQR beam qualities measurement with the Timepix4 detector","authors":"T. Genetay , L. Tlustos , M. Campbell , F. Bochud , P. Carbonez , J. Damet","doi":"10.1016/j.radmeas.2025.107570","DOIUrl":"10.1016/j.radmeas.2025.107570","url":null,"abstract":"<div><div>This work presents, to the best of the authors’ knowledge, the first attempt at reconstructing X-ray spectra with a hybrid pixel detector for radiation protection applications in the scattered field around fluoroscopy devices. The performance of the Timepix4 detector was evaluated under reference conditions using RQR beam qualities. A dedicated methodology was developed to correct for detection efficiency, explicitly accounting for contributions from Compton scattering and the photoelectric effect. Accuracy was assessed through Monte Carlo simulations and comparisons with published RQR reference spectra. In addition, particle fluence measurements obtained with Timepix4 were validated against values derived from kerma factors and ionisation chamber measurements performed in a calibration laboratory. The results show excellent agreement between reconstructed and reference spectra up to <span><math><mrow><mn>70</mn><mspace></mspace><mtext>keV</mtext></mrow></math></span>, with residuals below 1.7% and relative photon fluence shifts within 5%. At higher energies, discrepancies increase due to the low detection efficiency of the silicon sensor, requiring large correction factors and leading to greater statistical fluctuations. Nevertheless, the system demonstrated acceptable performance up to <span><math><mrow><mn>120</mn><mspace></mspace><mtext>keV</mtext></mrow></math></span>, with fluence shifts remaining below 16%. Linearity was confirmed across all beam qualities and intensities investigated, consistent with previous studies on earlier Timepix ASIC generations. Overall, these findings demonstrate that Timepix4 can provide reliable spectral and fluence measurements in reference X-ray beams, offering valuable information for radiation protection studies in scattered fields where conventional detectors are of limited use. Future improvements in readout bandwidth and spectral deconvolution methods are expected to extend its applicability to higher energies and clinical environments.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107570"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617332","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}
Rn-222 in water is not only a potential threat to human health, but also an important tracer for studying groundwater flow and crustal fracture system. The physical model of the existing method for measuring Rn-222 in water by the spray technique has not been made public. In this paper, a mathematical model for measuring Rn-222 concentration in water by spray method is established. A small spray device is designed and combined with RAD7 radon monitor to form a field measurement system for Rn-222 concentration in water. Six groups of field experiments were carried out in different locations around Yixin Lake in Hengyang Normal University, Hunan Province to verify the effectiveness of the model. The results show that the determination coefficient (R2) of the model is higher than 0.87, and the conversion efficiency of Rn-222 from water phase to gas phase is higher than 77 %, and the conversion efficiency is within two standard deviations. At the same time, the influence of leakage on the measurement results is analyzed. When the leakage rate exceeds 1 10−4 s−1, the measured Rn-222 concentration in water will be underestimated by about 20 %. The sensitivity of this measurement system is 0.0012 CPM/(Bq/m3). At a water temperature of 34.1 °C, the detection concentration range is from 0.7 to 133,689 Bq/m3.This study provides theoretical basis and technical support for rapid and accurate in-situ measurement of Rn-222 in natural water.
{"title":"Physical model construction and experimental verification of measuring Rn-222 concentration in water by spray method","authors":"Shicheng Luo, Zhongkai Fan, Ruomei Xie, Xinyue Yang, Xianfa Mao, Chenxi Zu, Feng Xiao, Hongbo Xu, Yi Liu, Hao You, Haoyu You, Jia Liu, Cheng Luo, Hongzhi Yuan, Yanliang Tan","doi":"10.1016/j.radmeas.2025.107573","DOIUrl":"10.1016/j.radmeas.2025.107573","url":null,"abstract":"<div><div>Rn-222 in water is not only a potential threat to human health, but also an important tracer for studying groundwater flow and crustal fracture system. The physical model of the existing method for measuring Rn-222 in water by the spray technique has not been made public. In this paper, a mathematical model for measuring Rn-222 concentration in water by spray method is established. A small spray device is designed and combined with RAD7 radon monitor to form a field measurement system for Rn-222 concentration in water. Six groups of field experiments were carried out in different locations around Yixin Lake in Hengyang Normal University, Hunan Province to verify the effectiveness of the model. The results show that the determination coefficient (R<sup>2</sup>) of the model is higher than 0.87, and the conversion efficiency of Rn-222 from water phase to gas phase is higher than 77 %, and the conversion efficiency is within two standard deviations. At the same time, the influence of leakage on the measurement results is analyzed. When the leakage rate exceeds 1 <span><math><mrow><mo>×</mo></mrow></math></span> 10<sup>−4</sup> s<sup>−1</sup>, the measured Rn-222 concentration in water will be underestimated by about 20 %. The sensitivity of this measurement system is 0.0012 CPM/(Bq/m<sup>3</sup>). At a water temperature of 34.1 °C, the detection concentration range is from 0.7 to 133,689 Bq/m<sup>3</sup>.This study provides theoretical basis and technical support for rapid and accurate in-situ measurement of Rn-222 in natural water.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107573"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617333","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}
CeF3-doped oxyfluoride scintillating glasses with the composition 50SiO2 – 20Al2O3 – 10BaF2 – 10Gd2O3 – 10Li2O (SABGL) were synthesized via the melt-quenching method under a carbon-reducing environment to stabilize Ce3+. The optical absorption spectra confirmed the characteristic 4f → 5d transitions of Ce3+ and a slight red shift associated with structural modifications at higher CeF3 contents. Photoluminescence (PL) measurements revealed strong blue emission centered at ∼438 nm, increasing monotonically with CeF3 concentration up to 1.5 wt%. Excitation spectra showed distinct bands from both Ce3+ and Gd3+, confirming efficient Gd3+ → Ce3+ energy transfer. Time-resolved PL decay exhibited tri-exponential behavior, indicating multiple Ce3+ environments typical of an amorphous glass host, with the fastest component reflecting efficient radiative relaxation. Under X-ray excitation, all samples produced clear blue radioluminescence, and X-ray imaging of an IC chip demonstrated spatial resolutions of 11.0–11.8 LP/mm, comparable to commercial BGO. Radiation-shielding parameters calculated using WinXCom showed high mass attenuation coefficients and elevated effective atomic numbers (Zeff ≈ 32–36 at low energies), attributed to the incorporation of Ba, Gd, and Ce. Compared with a Cs2O-Fe2O3-P2O5 reference glass, the SABGL system exhibited superior attenuation below ∼0.07 MeV, confirming its suitability for low-energy photon detection and shielding. Overall, the combined scintillation performance, high spatial resolution, and favorable photon-interaction properties demonstrate that CeF3-doped SABGL glasses, particularly the 1.5 wt% composition is promising, scalable candidates for low-energy X-ray imaging and radiation-shielding applications.
{"title":"Preparation and characterization of Ce3+-Doped oxyfluoride glass for X-ray scintillation and imaging applications","authors":"Prapon Lertloypanyachai , Tharadol Donjewphrai , Adisak Honok , Weerapong Chewpraditkul , Danping Chen , Piyachat Meejitpaisan , Anon Angnanon , Wuttichai Chaiphaksa , Supakit Yonphan , Jakrapong Kaewkhao","doi":"10.1016/j.radmeas.2025.107589","DOIUrl":"10.1016/j.radmeas.2025.107589","url":null,"abstract":"<div><div>CeF<sub>3</sub>-doped oxyfluoride scintillating glasses with the composition 50SiO<sub>2</sub> – 20Al<sub>2</sub>O<sub>3</sub> – 10BaF<sub>2</sub> – 10Gd<sub>2</sub>O<sub>3</sub> – 10Li<sub>2</sub>O (SABGL) were synthesized via the melt-quenching method under a carbon-reducing environment to stabilize Ce<sup>3+</sup>. The optical absorption spectra confirmed the characteristic 4f → 5d transitions of Ce<sup>3+</sup> and a slight red shift associated with structural modifications at higher CeF<sub>3</sub> contents. Photoluminescence (PL) measurements revealed strong blue emission centered at ∼438 nm, increasing monotonically with CeF<sub>3</sub> concentration up to 1.5 wt%. Excitation spectra showed distinct bands from both Ce<sup>3+</sup> and Gd<sup>3+</sup>, confirming efficient Gd<sup>3+</sup> → Ce<sup>3+</sup> energy transfer. Time-resolved PL decay exhibited tri-exponential behavior, indicating multiple Ce<sup>3+</sup> environments typical of an amorphous glass host, with the fastest component reflecting efficient radiative relaxation. Under X-ray excitation, all samples produced clear blue radioluminescence, and X-ray imaging of an IC chip demonstrated spatial resolutions of 11.0–11.8 LP/mm, comparable to commercial BGO. Radiation-shielding parameters calculated using WinXCom showed high mass attenuation coefficients and elevated effective atomic numbers (<em>Z</em><sub><em>eff</em></sub> ≈ 32–36 at low energies), attributed to the incorporation of Ba, Gd, and Ce. Compared with a Cs<sub>2</sub>O-Fe<sub>2</sub>O<sub>3</sub>-P<sub>2</sub>O<sub>5</sub> reference glass, the SABGL system exhibited superior attenuation below ∼0.07 MeV, confirming its suitability for low-energy photon detection and shielding. Overall, the combined scintillation performance, high spatial resolution, and favorable photon-interaction properties demonstrate that CeF<sub>3</sub>-doped SABGL glasses, particularly the 1.5 wt% composition is promising, scalable candidates for low-energy X-ray imaging and radiation-shielding applications.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107589"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790453","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 well-known CR-39, or poly allyl diglycol carbonate (PADC), has been widely used for personal neutron dosimetry for over 40 years. For providers of individual monitoring service (IMS) of neutron dose, it is necessary to establish an automatic reading system for CR-39 detectors in two aspects: to quickly measure a large number of detectors returned from users, and to ensure precision and accuracy that meet the requirements of the ISO/IEC 17025 standard. In this study, a novel high-speed and precise system composed of three parts was developed: (I) image acquisition of etched tracks on CR-39 detectors using an optical microscope with an autofocusing module and a high-speed scanning stage, (II) image processing of the tracks using an integrated software for automatic pit-counting on CR-39 (ISAP-39), including dedicated image processing in two steps, judging exposure in screening mode and evaluating neutron dose in precise reading mode, and (III) data reviewing by dosimetry experts. In the performance evaluation of the system, the following results were confirmed: high-speed scanning with 30 s per detector, high image-processing performance with 0 % false positive detection rate for neutron-induced tracks in screening and over 83 % true positive rate in precise reading, capability to describe differences in track features due to different neutron sources, and capability for precise dose measurements, including coefficient of variation, linearity, and track counting uncertainties. Moreover, in the operational study, the system was confirmed to be valid in terms of the screening function, threshold setting, pass rate stability in screening, and validity of precise reading and data reviewing. Consequently, the CR-39 reading system was proven to have sufficient performance in terms of reading speed and measurement precision.
{"title":"Development of a high-speed and precise automatic reading system of CR-39 plastic nuclear track detector for neutron dose measurements","authors":"Takuya Hashizume, Ryuji Akino, Hiroshi Sekiguchi, Chizuru Ojima, Yumi Kanie, Masami Sonda, Hiroki Hakamata, Akifumi Suzuki, Mitsuo Tsubomatsu, So Kitazawa, Yuki Oda","doi":"10.1016/j.radmeas.2025.107572","DOIUrl":"10.1016/j.radmeas.2025.107572","url":null,"abstract":"<div><div>The well-known CR-39, or poly allyl diglycol carbonate (PADC), has been widely used for personal neutron dosimetry for over 40 years. For providers of individual monitoring service (IMS) of neutron dose, it is necessary to establish an automatic reading system for CR-39 detectors in two aspects: to quickly measure a large number of detectors returned from users, and to ensure precision and accuracy that meet the requirements of the ISO/IEC 17025 standard. In this study, a novel high-speed and precise system composed of three parts was developed: (I) image acquisition of etched tracks on CR-39 detectors using an optical microscope with an autofocusing module and a high-speed scanning stage, (II) image processing of the tracks using an integrated software for automatic pit-counting on CR-39 (ISAP-39), including dedicated image processing in two steps, judging exposure in screening mode and evaluating neutron dose in precise reading mode, and (III) data reviewing by dosimetry experts. In the performance evaluation of the system, the following results were confirmed: high-speed scanning with 30 s per detector, high image-processing performance with 0 % false positive detection rate for neutron-induced tracks in screening and over 83 % true positive rate in precise reading, capability to describe differences in track features due to different neutron sources, and capability for precise dose measurements, including coefficient of variation, linearity, and track counting uncertainties. Moreover, in the operational study, the system was confirmed to be valid in terms of the screening function, threshold setting, pass rate stability in screening, and validity of precise reading and data reviewing. Consequently, the CR-39 reading system was proven to have sufficient performance in terms of reading speed and measurement precision.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107572"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790454","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}
When performing real-time dosimetry using an active-type dosimeter during clinical fluoroscopic procedures, angular dependence of dosimeter response should be taken into account. Our research group addressed this issue and proposed a triple-type dosimeter that can determine the incident angle of scattered X-rays. The triple-type detector consists of three active dosimeters. The two side dosimeters have slope filters to enhance the angular dependence and are intentionally tilted. The central dosimeter faces forward. The incident angle of X-rays () is estimated using the signal differences between the central dosimeter and the left and/or right dosimeters. Then, the absolute dose is determined by correcting the angular dependence of the central dosimeter based on the estimated . In order to verify the concept of the triple-type dosimeter, we conducted a proof-of-concept experiment using clinical X-ray fluoroscopic equipment. Scattered X-rays were generated by irradiating an elliptical cylindrical water phantom. The response of the triple-type dosimeter was evaluated by rotating it to vary the incident angle of scattered X-rays generated by the water phantom. The proposed dosimetry system could estimate the over an angular range of ±80° (with uncertainty of 1.35°), which is 30° wider than the previous version, and successfully determined the absolute doses after correction for the angular dependence of the dosimeter. Although the active-type dosimeter had a systematic uncertainty related to the angular dependence of ±15.2 %, our system succeeded in reducing the systematic uncertainty to ±3.2 %.
{"title":"A novel wearable dosimeter system that can analyze the incident direction of X-rays for medical dosimetry – Improvements to the detector arrangements and analysis algorithm –","authors":"Takashi Asahara , Rina Nishigami , Daiki Kobayashi , Natsumi Kimoto , Sota Goto , Kazuki Takegami , Rin Ishii , Mana Mitani , Mitsugi Honda , Toshihiro Iguchi , Hiroaki Hayashi","doi":"10.1016/j.radmeas.2025.107592","DOIUrl":"10.1016/j.radmeas.2025.107592","url":null,"abstract":"<div><div>When performing real-time dosimetry using an active-type dosimeter during clinical fluoroscopic procedures, angular dependence of dosimeter response should be taken into account. Our research group addressed this issue and proposed a triple-type dosimeter that can determine the incident angle of scattered X-rays. The triple-type detector consists of three active dosimeters. The two side dosimeters have slope filters to enhance the angular dependence and are intentionally tilted. The central dosimeter faces forward. The incident angle of X-rays (<span><math><mrow><msub><mi>θ</mi><mtext>in</mtext></msub></mrow></math></span>) is estimated using the signal differences between the central dosimeter and the left and/or right dosimeters. Then, the absolute dose is determined by correcting the angular dependence of the central dosimeter based on the estimated <span><math><mrow><msub><mi>θ</mi><mtext>in</mtext></msub></mrow></math></span>. In order to verify the concept of the triple-type dosimeter, we conducted a proof-of-concept experiment using clinical X-ray fluoroscopic equipment. Scattered X-rays were generated by irradiating an elliptical cylindrical water phantom. The response of the triple-type dosimeter was evaluated by rotating it to vary the incident angle of scattered X-rays generated by the water phantom. The proposed dosimetry system could estimate the <span><math><mrow><msub><mi>θ</mi><mtext>in</mtext></msub></mrow></math></span> over an angular range of ±80° (with uncertainty of 1.35°), which is 30° wider than the previous version, and successfully determined the absolute doses after correction for the angular dependence of the dosimeter. Although the active-type dosimeter had a systematic uncertainty related to the angular dependence of ±15.2 %, our system succeeded in reducing the systematic uncertainty to ±3.2 %.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107592"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790520","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}
During computed tomography (CT) examination, radiation exposures should be appropriately managed taking into considering the effects of bowtie filter, the heel effect and over-beaming effect. Furthermore, the analysis of an X-ray incident direction is important. The purpose of this study is to develop a procedure to obtain two-dimensional (2D) internal dose distributions based on actual measurements of surface dose distribution and central internal dose data. Experiments were conducted using a clinical CT scanner and four cylindrical polyacetal resin (POM) phantoms having diameters of 15–30 cm. The entrance surface doses and the central internal dose were measured by placing the optically stimulated luminescence (OSL) dosimeters on the surface and inner part of the phantom, respectively, during helical CT scans. The X-ray incident direction at the slice containing the dosimeter was estimated based on the noise distribution analysis of the CT image. Then, circumferential surface dose distributions were determined as a function of the X-ray incident direction. Based on these experimental data, we succeeded in visualizing the 2D dose distributions. The obtained dose distribution was inhomogeneous, clearly reflecting the influence of factors such as the heel effect. The uncertainty due to our methodology was estimated to be from 4.3 % to 7.4 %. Our methodology needs central internal dose data, and the absence of this data introduced additional systematic uncertainties of +6.9 % to −11.4 %. In conclusion, correcting for the effect of the X-ray incident directions for entrance surface dose and adding the central inner dose data can improve the reliability of the internal dose distribution.
{"title":"Experimental approach of internal dose map visualization during helical CT examinations: importance of X-ray incident direction analysis and central internal dose estimation","authors":"Hiroaki Hayashi , Kazuki Takegami , Rina Nishigami , Daiki Kobayashi , Sota Goto , Takashi Asahara , Natsumi Kimoto , Masaki Takemitsu , Rin Ishii , Shinichi Morimoto , Motochika Maki","doi":"10.1016/j.radmeas.2025.107586","DOIUrl":"10.1016/j.radmeas.2025.107586","url":null,"abstract":"<div><div>During computed tomography (CT) examination, radiation exposures should be appropriately managed taking into considering the effects of bowtie filter, the heel effect and over-beaming effect. Furthermore, the analysis of an X-ray incident direction is important. The purpose of this study is to develop a procedure to obtain two-dimensional (2D) internal dose distributions based on actual measurements of surface dose distribution and central internal dose data. Experiments were conducted using a clinical CT scanner and four cylindrical polyacetal resin (POM) phantoms having diameters of 15–30 cm. The entrance surface doses and the central internal dose were measured by placing the optically stimulated luminescence (OSL) dosimeters on the surface and inner part of the phantom, respectively, during helical CT scans. The X-ray incident direction at the slice containing the dosimeter was estimated based on the noise distribution analysis of the CT image. Then, circumferential surface dose distributions were determined as a function of the X-ray incident direction. Based on these experimental data, we succeeded in visualizing the 2D dose distributions. The obtained dose distribution was inhomogeneous, clearly reflecting the influence of factors such as the heel effect. The uncertainty due to our methodology was estimated to be from 4.3 % to 7.4 %. Our methodology needs central internal dose data, and the absence of this data introduced additional systematic uncertainties of +6.9 % to −11.4 %. In conclusion, correcting for the effect of the X-ray incident directions for entrance surface dose and adding the central inner dose data can improve the reliability of the internal dose distribution.</div></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":"191 ","pages":"Article 107586"},"PeriodicalIF":2.2,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738029","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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