This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in ...This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in an inter-comparison exercise. Although the results of LabSOCS and ANGLE for ^(241)Am emitting lowenergy gamma rays were not very satisfactory, all of the three efficiency calibration methods passed acceptance criteria. The results confirmed the reliability of the calculation codes ANGLE and LabSOCS as alternative efficiency calibration methods in high-purity-germanium gamma spectrometry. This study is likely to promote the further application of the ANGLE and LabSOCS calculation codes in radioactivity measurements.展开更多
In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-24...In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-241 in the lungs,and Pb-210 in the skull.Throughout the measurements,the radiation background is the key factor that determines the sensitivity of the counter.Therefore,to facilitate in vivo measurements,a well-designed shielding room is required to create a low-background environment.However,because the compositions of the radiation background are quite complicated,the respective contributions from each source remain obscure,which places a considerable burden on seeking an optimized design of shielding rooms that strikes the optimum balance between the construction cost and background suppression effect.In this study,we conducted a systematic experimental investigation on the radiation background outside and inside four representative body counters with assorted designs using a variety of radiation detectors,including high-purity germanium detectors,CdZnTe detector,radon emanometer,and gamma-ray dosimeter.By carefully controlling the experimental conditions and synergetic analysis of the measurement results,in conjunction with previous studies,we separated and determined the relative contributions induced by environmental radiation(4%),airborne radon and its daughters(2%),the normal radioactivity of human subjects arising from K-40(58%),cosmic rays(12%),and radioactivity in shielding materials and measuring instruments(24%).Furthermore,based on these results,we discuss practical guidelines to design a shielding room for body counters.展开更多
A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(1...A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(13.5 MeV,13.8 MeV,14.1 MeV,14.4 MeV,14.8 MeV)relative to the^(93)Nb(n,2n)^(92)mNb reaction CS.The target was high-purity natural Xe gas under high pressure.The T(d,n)4He reaction produces neutrons.TALYS code(version 1.95)for nuclear reactions was used for calculations,with default parameters and nuclear level density models.The uncertainties in the measured CS data were thoroughly analyzed using the covariance analysis method.The results were compared with theoretical values,evaluation data,and previous experimental findings.CS data of the 134Xe(n,2n)133mXe and 134Xe(n,2n)133gXe reactions and the corresponding isomeric CS ratios at 13.5 MeV,13.8 MeV,and 14.1 MeV neutron energies are reported for the first time.This research advances our knowledge of pre-equilibrium emission in the(n,2n)reaction channel by resolving inconsistencies in the Xe data.展开更多
Introduction:The effective dose caused by the external exposure of medical radiation workers has dramatically declined in China.By contrast,less attention has been given to internal exposure to radiation.This study ai...Introduction:The effective dose caused by the external exposure of medical radiation workers has dramatically declined in China.By contrast,less attention has been given to internal exposure to radiation.This study aimed to describe the national monitoring of the internal exposure of Chinese nuclear medicine(NM)workers from 2021 to 2023.These findings provide essential baseline data for enhancing radiation protection protocols in NM facilities and optimizing national internal exposure monitoring.Methods:All the non-military hospitals in China with an NM program were investigated.Portable gamma spectrometers were used to measure the ^(131)I activities of the thyroid of staff members at ^(131)I treatment sites.Results:A total of 998 hospitals in China had an NM program in 2023.Detectable rate(measurements above minimum detectable activity)decreased from 26.2%in 2021 to 20.1%in 2023.The proportion of measurements exceeding 1.0×10^(2) Bq decreased from 12.8%in 2021 to 10.0%in 2023.The detectable rate varied with job categories(P=0.001),with the detectable rate of cleaners being the highest.Conclusions:In China,^(131)I was detected in the thyroid of about one-fifth of the subjects working at radioiodine treatment sites.Detectable rate exhibited a slow downward trend in recent years.展开更多
Objective:To evaluate the effectiveness of a portable thyroid radioiodine meter in on-site monitoring to enhance the monitoring precision of radioiodine inhaled by nuclear medicine staff and patients.Methods:A portabl...Objective:To evaluate the effectiveness of a portable thyroid radioiodine meter in on-site monitoring to enhance the monitoring precision of radioiodine inhaled by nuclear medicine staff and patients.Methods:A portable thyroid radioiodine meter was developed to measure the 131I activity in the thyroid.Performance tests of the portable thyroid radioiodine meter were conducted using calibration sources and testing methodologies adhering to national metrological standards.Results:The thyroid radioiodine meter exhibited integral non-linearity,8-h measurement stability,measurement linearity,and an energy resolution of 0.42%,1.05%,1.56%,and 7.11%,respectively for ^(137)Cs at 661.66 keV.Additionally,its minimum detectable activity for ^(131)I at 364.49 keV was approximately 22 Bq(10 min).Conclusion:The developed thyroid radioiodine meter features elevated performance and great potential for application in nuclear medicine and monitoring of responses to nuclear or radiological emergencies.展开更多
After the nuclear accident at the Fukushima Daiichi Nuclear Power Plant(Fukushima nuclear accident)in 2011,Japan quickly took emergency measures to reduce radiation hazards posed by the released radioactive materials....After the nuclear accident at the Fukushima Daiichi Nuclear Power Plant(Fukushima nuclear accident)in 2011,Japan quickly took emergency measures to reduce radiation hazards posed by the released radioactive materials.As a neighboring country of Japan across the East China Sea,China has also taken some corresponding prevention and control measures.China has continuously strengthened the monitoring of radioactivity in food in recent years.This paper discusses the revision of standards for radioactivity in food,the improvement of methods and equipment,and the updating of monitoring systems performed in China and Japan over the last ten years after the Fukushima Daiichi accident.In addition,this paper outlines the recent problems left over from the nuclear accident,puts forward some views on the progress of important topics,and gives some thoughts and prospects on the further improvement of the monitoring systems of radioactivity in food in China.展开更多
Objective:To explore the concentration level of radionuclide in mushrooms in northeast China,and to analyze the risk of the effective dose of edible mushrooms to the human body.Methods:A total of 68 samples of 18 spec...Objective:To explore the concentration level of radionuclide in mushrooms in northeast China,and to analyze the risk of the effective dose of edible mushrooms to the human body.Methods:A total of 68 samples of 18 species of mushrooms from three regions in northeast China and Beijing as control were collected from 2017 to 2020.The activity of radionuclide in mushrooms was measured by gammaspectrometry,and the activity was analyzed by statistical analysis.The relationship between ^(137)Cs and ^(40)K content in mushrooms was explored.Results:^(238)U was undetected in all samples.The activity concentration of ^(226)Ra,^(232)Th,^(40)K,^(137)Cs were in range of 1–34.3,2.26–32.3,208–2,388 and 0.6–130.3 Bq/kg,respectively.The ^(137)Cs and ^(40)K concentrations in mushrooms were not correlated.The risk analysis of radioactivity in the collected mushrooms showed that the highest effective dose of the 18 kinds of mushrooms was 0.042 mSv.Conclusion:The radionuclide content of mushrooms in northeast China is within the normal range.The mushrooms will not cause risk to human health.展开更多
Introduction:For investigating the potential contaminations from the applications of nuclear energy and techniques,the radioactivity of both natural and artificial radionuclides in foods in China were surveyed during ...Introduction:For investigating the potential contaminations from the applications of nuclear energy and techniques,the radioactivity of both natural and artificial radionuclides in foods in China were surveyed during the period of 2012–2019,and the public’s exposure to radiation due to the consumption of these foods were estimated.Methods:The surveillance was conducted using the National Monitoring Network for Radioactivity in Food from 2012 to 2019.Food samples were collected,and radioactivity was determined using HPGe gammaray spectrometer by local institutes.Results:From 2012 to 2019,a total of 6,129 food samples including those collected around nuclear power plants and uranium mines were collected and analyzed,and no samples with activity concentrations of 238U,228Ra,226Ra,40K,or 137Cs were found to exceed Chinese national standards.Among the 7 types of surveyed foods,the natural radionuclide levels of tea and seaweed were relatively high,and the activity concentration of 137Cs in milk and dairy products was higher than that of other foods.Conclusions and Implications for Public Health Practice:The results of all the surveyed samples were within the scope of Chinese national standards.Different regions should improve monitoring systems,establish corresponding food emergency warning systems,and prepare strategies and measures for handling public health accidents.展开更多
The reaction cross-sections of ^(124)Xe(n,2n)^(123)Xe,^(126)Xe(n,2n)^(125)Xe,^(128)Xe(n,2n)^(127)Xe,^(130)Xe(n,2n)^(129)mXe,^(132)Xe(n,2n)^(131)mXe,^(130)Xe(n,p)^(130)I,^(131)Xe(n,p)^(131)I,and ^(132)Xe(n,p)^(132)I we...The reaction cross-sections of ^(124)Xe(n,2n)^(123)Xe,^(126)Xe(n,2n)^(125)Xe,^(128)Xe(n,2n)^(127)Xe,^(130)Xe(n,2n)^(129)mXe,^(132)Xe(n,2n)^(131)mXe,^(130)Xe(n,p)^(130)I,^(131)Xe(n,p)^(131)I,and ^(132)Xe(n,p)^(132)I were measured at the 13.5,13.8,14.1,14.4,and 14.8 MeV neutron energies.The monoenergetic neutrons were generated via the ^(3)H(d,n)^(4)He reaction at the China Academy of Engineering Physics using the K-400 Neutron Generator with a solid ^(3)H-Ti target.A high-purity germanium detector was employed to measure the activities of the product.The reactions ^(93)Nb(n,2n)^(92m)Nb and ^(27)Al(n,α)^(24)Na were adopted for neutron flux calibration.The cross sections of the(n,2n)and(n,p)reactions of the xenon isotopes were obtained within the 13-15 MeV neutron energy range.These cross-sections were then compared with the IAEA-exchange format(EXFOR)database-derived experimental data,together with the evaluation results of the CENDL-3,ENDF/B-Ⅷ.0,JENDL-4.0,RUSFOND,and JEFF-3.3 data libraries,as well as the theoretical excitation function obtained using the TALYS-1.95 code.The cross-sections of the reactions(except for the ^(124)Xe(n,2n)^(123)Xe and ^(132)Xe(n,p)^(132)I)at 13.5,13.8,and 14.1 MeV are reported for the first time in this study.The obtained results are beneficial in providing better cross-section constraints for the reactions in the 13-15 MeV region,thus improving the quality of the corresponding database.Meanwhile,these data can also be used for the verification of relevant nuclear reaction model parameters.展开更多
基金supported by the Support Program of the Ministry of Science and Technology(No.2014FY211000)the National Key Technology Research and Development Program(No.2013BAK03B05)
文摘This study reports the performances of efficiency calibrations for high-purity-germanium gamma-ray spectrometry using the source-, Laboratory Sourceless Object Calibration Software(LabSOCS)-and ANGLE-based methods in an inter-comparison exercise. Although the results of LabSOCS and ANGLE for ^(241)Am emitting lowenergy gamma rays were not very satisfactory, all of the three efficiency calibration methods passed acceptance criteria. The results confirmed the reliability of the calculation codes ANGLE and LabSOCS as alternative efficiency calibration methods in high-purity-germanium gamma spectrometry. This study is likely to promote the further application of the ANGLE and LabSOCS calculation codes in radioactivity measurements.
基金supported by the Central University Basic Scientific Research Business Expenses Special Funds under the project name Research on Applied Physics under Low 385 Radiation Background(No. 2018NTST07)2021 Nuclear and Radiation Safety Technic Evaluation Project,Ministry of Ecology and Environment (No.NSCCG2021-052)
文摘In vivo measurement of radioactivity based on various body counters is arguably the leading measure used to determine the distribution and activity of radionuclides in human subjects,such as I-131 in the thyroid,Am-241 in the lungs,and Pb-210 in the skull.Throughout the measurements,the radiation background is the key factor that determines the sensitivity of the counter.Therefore,to facilitate in vivo measurements,a well-designed shielding room is required to create a low-background environment.However,because the compositions of the radiation background are quite complicated,the respective contributions from each source remain obscure,which places a considerable burden on seeking an optimized design of shielding rooms that strikes the optimum balance between the construction cost and background suppression effect.In this study,we conducted a systematic experimental investigation on the radiation background outside and inside four representative body counters with assorted designs using a variety of radiation detectors,including high-purity germanium detectors,CdZnTe detector,radon emanometer,and gamma-ray dosimeter.By carefully controlling the experimental conditions and synergetic analysis of the measurement results,in conjunction with previous studies,we separated and determined the relative contributions induced by environmental radiation(4%),airborne radon and its daughters(2%),the normal radioactivity of human subjects arising from K-40(58%),cosmic rays(12%),and radioactivity in shielding materials and measuring instruments(24%).Furthermore,based on these results,we discuss practical guidelines to design a shielding room for body counters.
基金supported by the National Natural science Foundation of China(Nos.11875016,12165006).
文摘A lead-shielded HPGe detector and offlineγ-ray spectra of the residual product were used to measure the cross section(CS)and ratios of isomeric CS(σm/σg)in^(134)Xe(n,2n)^(133m),gXe reactions at different energies(13.5 MeV,13.8 MeV,14.1 MeV,14.4 MeV,14.8 MeV)relative to the^(93)Nb(n,2n)^(92)mNb reaction CS.The target was high-purity natural Xe gas under high pressure.The T(d,n)4He reaction produces neutrons.TALYS code(version 1.95)for nuclear reactions was used for calculations,with default parameters and nuclear level density models.The uncertainties in the measured CS data were thoroughly analyzed using the covariance analysis method.The results were compared with theoretical values,evaluation data,and previous experimental findings.CS data of the 134Xe(n,2n)133mXe and 134Xe(n,2n)133gXe reactions and the corresponding isomeric CS ratios at 13.5 MeV,13.8 MeV,and 14.1 MeV neutron energies are reported for the first time.This research advances our knowledge of pre-equilibrium emission in the(n,2n)reaction channel by resolving inconsistencies in the Xe data.
文摘Introduction:The effective dose caused by the external exposure of medical radiation workers has dramatically declined in China.By contrast,less attention has been given to internal exposure to radiation.This study aimed to describe the national monitoring of the internal exposure of Chinese nuclear medicine(NM)workers from 2021 to 2023.These findings provide essential baseline data for enhancing radiation protection protocols in NM facilities and optimizing national internal exposure monitoring.Methods:All the non-military hospitals in China with an NM program were investigated.Portable gamma spectrometers were used to measure the ^(131)I activities of the thyroid of staff members at ^(131)I treatment sites.Results:A total of 998 hospitals in China had an NM program in 2023.Detectable rate(measurements above minimum detectable activity)decreased from 26.2%in 2021 to 20.1%in 2023.The proportion of measurements exceeding 1.0×10^(2) Bq decreased from 12.8%in 2021 to 10.0%in 2023.The detectable rate varied with job categories(P=0.001),with the detectable rate of cleaners being the highest.Conclusions:In China,^(131)I was detected in the thyroid of about one-fifth of the subjects working at radioiodine treatment sites.Detectable rate exhibited a slow downward trend in recent years.
文摘Objective:To evaluate the effectiveness of a portable thyroid radioiodine meter in on-site monitoring to enhance the monitoring precision of radioiodine inhaled by nuclear medicine staff and patients.Methods:A portable thyroid radioiodine meter was developed to measure the 131I activity in the thyroid.Performance tests of the portable thyroid radioiodine meter were conducted using calibration sources and testing methodologies adhering to national metrological standards.Results:The thyroid radioiodine meter exhibited integral non-linearity,8-h measurement stability,measurement linearity,and an energy resolution of 0.42%,1.05%,1.56%,and 7.11%,respectively for ^(137)Cs at 661.66 keV.Additionally,its minimum detectable activity for ^(131)I at 364.49 keV was approximately 22 Bq(10 min).Conclusion:The developed thyroid radioiodine meter features elevated performance and great potential for application in nuclear medicine and monitoring of responses to nuclear or radiological emergencies.
文摘After the nuclear accident at the Fukushima Daiichi Nuclear Power Plant(Fukushima nuclear accident)in 2011,Japan quickly took emergency measures to reduce radiation hazards posed by the released radioactive materials.As a neighboring country of Japan across the East China Sea,China has also taken some corresponding prevention and control measures.China has continuously strengthened the monitoring of radioactivity in food in recent years.This paper discusses the revision of standards for radioactivity in food,the improvement of methods and equipment,and the updating of monitoring systems performed in China and Japan over the last ten years after the Fukushima Daiichi accident.In addition,this paper outlines the recent problems left over from the nuclear accident,puts forward some views on the progress of important topics,and gives some thoughts and prospects on the further improvement of the monitoring systems of radioactivity in food in China.
文摘Objective:To explore the concentration level of radionuclide in mushrooms in northeast China,and to analyze the risk of the effective dose of edible mushrooms to the human body.Methods:A total of 68 samples of 18 species of mushrooms from three regions in northeast China and Beijing as control were collected from 2017 to 2020.The activity of radionuclide in mushrooms was measured by gammaspectrometry,and the activity was analyzed by statistical analysis.The relationship between ^(137)Cs and ^(40)K content in mushrooms was explored.Results:^(238)U was undetected in all samples.The activity concentration of ^(226)Ra,^(232)Th,^(40)K,^(137)Cs were in range of 1–34.3,2.26–32.3,208–2,388 and 0.6–130.3 Bq/kg,respectively.The ^(137)Cs and ^(40)K concentrations in mushrooms were not correlated.The risk analysis of radioactivity in the collected mushrooms showed that the highest effective dose of the 18 kinds of mushrooms was 0.042 mSv.Conclusion:The radionuclide content of mushrooms in northeast China is within the normal range.The mushrooms will not cause risk to human health.
文摘Introduction:For investigating the potential contaminations from the applications of nuclear energy and techniques,the radioactivity of both natural and artificial radionuclides in foods in China were surveyed during the period of 2012–2019,and the public’s exposure to radiation due to the consumption of these foods were estimated.Methods:The surveillance was conducted using the National Monitoring Network for Radioactivity in Food from 2012 to 2019.Food samples were collected,and radioactivity was determined using HPGe gammaray spectrometer by local institutes.Results:From 2012 to 2019,a total of 6,129 food samples including those collected around nuclear power plants and uranium mines were collected and analyzed,and no samples with activity concentrations of 238U,228Ra,226Ra,40K,or 137Cs were found to exceed Chinese national standards.Among the 7 types of surveyed foods,the natural radionuclide levels of tea and seaweed were relatively high,and the activity concentration of 137Cs in milk and dairy products was higher than that of other foods.Conclusions and Implications for Public Health Practice:The results of all the surveyed samples were within the scope of Chinese national standards.Different regions should improve monitoring systems,establish corresponding food emergency warning systems,and prepare strategies and measures for handling public health accidents.
基金Supported by the National Natural Science Foundation of China(11875016,12165006)。
文摘The reaction cross-sections of ^(124)Xe(n,2n)^(123)Xe,^(126)Xe(n,2n)^(125)Xe,^(128)Xe(n,2n)^(127)Xe,^(130)Xe(n,2n)^(129)mXe,^(132)Xe(n,2n)^(131)mXe,^(130)Xe(n,p)^(130)I,^(131)Xe(n,p)^(131)I,and ^(132)Xe(n,p)^(132)I were measured at the 13.5,13.8,14.1,14.4,and 14.8 MeV neutron energies.The monoenergetic neutrons were generated via the ^(3)H(d,n)^(4)He reaction at the China Academy of Engineering Physics using the K-400 Neutron Generator with a solid ^(3)H-Ti target.A high-purity germanium detector was employed to measure the activities of the product.The reactions ^(93)Nb(n,2n)^(92m)Nb and ^(27)Al(n,α)^(24)Na were adopted for neutron flux calibration.The cross sections of the(n,2n)and(n,p)reactions of the xenon isotopes were obtained within the 13-15 MeV neutron energy range.These cross-sections were then compared with the IAEA-exchange format(EXFOR)database-derived experimental data,together with the evaluation results of the CENDL-3,ENDF/B-Ⅷ.0,JENDL-4.0,RUSFOND,and JEFF-3.3 data libraries,as well as the theoretical excitation function obtained using the TALYS-1.95 code.The cross-sections of the reactions(except for the ^(124)Xe(n,2n)^(123)Xe and ^(132)Xe(n,p)^(132)I)at 13.5,13.8,and 14.1 MeV are reported for the first time in this study.The obtained results are beneficial in providing better cross-section constraints for the reactions in the 13-15 MeV region,thus improving the quality of the corresponding database.Meanwhile,these data can also be used for the verification of relevant nuclear reaction model parameters.
