The multiple nuclides identification algorithm with low consumption and strong robustness is crucial for rapid radioactive source searching.This study investigates the design of a low-consumption multiple nuclides ide...The multiple nuclides identification algorithm with low consumption and strong robustness is crucial for rapid radioactive source searching.This study investigates the design of a low-consumption multiple nuclides identification algorithm for portable gamma spectrometers.First,the gamma spectra of 12 target nuclides(including the background case)were measured to create training datasets.The characteristic energies,obtained through energy calibration and full-energy peak addresses,are utilized as input features for a neural network.A large number of single-and multiple-nuclide training datasets are generated using random combinations and small-range drifting.Subsequently,a multi-label classification neural network based on a binary cross-entropy loss function is applied to export the existence probability of certain nuclides.The designed algorithm effectively reduces the computation time and storage space required by the neural network and has been successfully implemented in a portable gamma spectrometer with a running time of t_(r)<2 s.Results show that,in both validation and actual tests,the identification accuracy of the designed algorithm reaches 94.8%,for gamma spectra with a dose rate of d≈0.5μSv∕h and a measurement time t_(m)=60 s.This improves the ability to perform rapid on-site nuclide identification at important sites.展开更多
Objective:To assess the detection efficiencies of liquid radioisotopes in a well-type NaI(Tl)gamma spectrometer,focusing on the short-lived isotopes^(99)Tcm,^(131)I,and^(18)F.Methods:The detection efficiencies of liqu...Objective:To assess the detection efficiencies of liquid radioisotopes in a well-type NaI(Tl)gamma spectrometer,focusing on the short-lived isotopes^(99)Tcm,^(131)I,and^(18)F.Methods:The detection efficiencies of liquid 99Tcm,131I,and 18F in a well-type NaI(Tl)gamma spectrometer were systematically investigated through calibration experiments and Monte Carlo simulations,and accounting for the coincidence-summing effect.Results:The results indicated that the detection efficiencies of^(99)Tcm,^(131)I,and^(18)F varied from 64.4%to 72.3%,34.8%-43.1%and 27.3%-28.5%for different sample volumes ranging from 15 mL to 80 mL,respectively.The simulated detection efficiencies were highly consistent with the experimental results,with a largest relative deviation of 5%for the 3 radionuclides and 4 different sample volumes.Conclusion:The consistent results between the calibration experiments and Monte Carlo simulations reveal that this measuring device possesses high detection efficiencies of 99Tcm,131I,and 18F,making it suitable for measuring low-level activity radioactive liquids,such as radioactive waste liquids to be discharged.展开更多
Iodine-131 is a highly toxic and volatile artificial radionuclide that is easily inhaled or ingested by the human body and selectively accumulates in thyroid tissue.With the development of nuclear medicine and nuclear...Iodine-131 is a highly toxic and volatile artificial radionuclide that is easily inhaled or ingested by the human body and selectively accumulates in thyroid tissue.With the development of nuclear medicine and nuclear power plants,the unintended release of ^(131)I has been widely studied,and the in vivo measurement of ^(131)I in the thyroid has become a research hotspot in the field of radiation protection.In recent decades,several methods and devices have been developed for in vivo measurements with respect to different measurement purposes and requirements.In this work,for more accurate determinations of individual ^(131)I in the thyroid in the field,the uncertainties of measurements by using portable gamma spectrometers were reviewed and analyzed,and monitoring strategies for improving the accuracy were proposed and prospected.展开更多
The measurement principle and analysis method of natural gamma-ray spectra using Nal(T1) scintillation spectrometer are briefly described first, thed block diagrams of the HD-8004 Nal(T1) gamma-ray spectrometer. Fina...The measurement principle and analysis method of natural gamma-ray spectra using Nal(T1) scintillation spectrometer are briefly described first, thed block diagrams of the HD-8004 Nal(T1) gamma-ray spectrometer. Finally, sample measurements are listed and discussed. The results are quite promising. Based on the analysis of these measurements, measures to improve the accuracy of spectrum measurement are proposed. It is well hoped that these measures call contribute to the development and application of gamma-ray spectrum measurement.展开更多
This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in...This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in natural water are provided by natural and artificial radionuclides such as ^(40) K,^(137)Cs,and radionuclides belonging to ^(238)U and ^(232)Th series.The main a emitters related to gamma emissions in natural water are ^(224)Ra(240.98 keV)and ^(226)Ra(186.21 keV),and the β^(-) emitters are ^(40) K(1460.85 keV),^(214)Bi(609.31 keV),^(208)Tl(583.19 keV),and ^(214)Pb(351.93 keV).The formula for gross α and β^(-) activity concentration is based on these radionuclides,and the short half-life decay products are considered in the calculation.The detection efficiency of the device across energy region(0–3 MeV)is obtained through Monte Carlo simulation,and a calibration experiment is conducted to verify the simulation results.Gamma radioactivity is measured continuously for 114 d in Pixian County and Dongfeng Canal located in the Zouma River,Chengdu,Sichuan Province,China.A comparison of the calculation results and monitoring data from the Sichuan Management and Monitoring Center Station of Radioactive Environment indicates that the percentage and absolute error of a activity concentration is lower than 53%and 0.02 Bq/L,respectively,and that of β-activity concentration is lower than 33.2%and 0.016 Bq/L,respectively.The method can rapidly determine gross α and β^(-) activity concentrations in natural water online.展开更多
Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase min...Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.展开更多
The activity concentrations of natural radionuclides <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K, were measured in (16) sandstone samples collected from two regions of Sau...The activity concentrations of natural radionuclides <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K, were measured in (16) sandstone samples collected from two regions of Saudi Arabia, Region 1 (Al Wajh on Red Sea coast and Al Ula north-East of Medina), Region 2 (North of Al Ula and Az Zabirah, North-West of Hail) by (HPGe gamma spectrometer). The activity concentration average values of the radionuclides <sup>226</sup>Ra, <sup>232</sup>Th, and <sup>40</sup>K in the sandstone samples (Region 1) ranged from 10.97 ± 0.43, 27.68 ± 0.37 and 64.56 ± 0.74 Bq/kg respectively. These values are less than the international values reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000), in (Region 2), average values ranged from 2465.49 ± 0.00, 2042.00 ± 0.00 and 2259.65 ± 0.64 Bq/kg respectively. These values are higher than the values reported by (UNSCEAR, 2000). Average values of radium equivalent activity Ra<sub>eq</sub> (Bq/Kg), absorbed dose rate D (nGy/h), annual effective radiation dose D<sub>eff</sub> (mSv/y), External index (H<sub>ex</sub>) and Internal index (H<sub>in</sub>) were in (region 1) 21.13, 27.22, 11.75, 0.07 and 0.10 respectively, in (region 2) 5775.19, 1787.78, 846.58, 11.57 and 15.64 respectively. These results are lower (except annual effective radiation dose) in (region 1) and higher in (region 2) than the world recommended values by (UNSCEAR, 2000). Also, samples were analyzed by Atomic Absorption spectrometer (AAS) for Al, Ca, Fe, K, Mg and Bi in % elements concentrations. Average value in (region 1) (Al Wajh and Al Ula) are 4.42, 0.41, 1.37, 0.04 and 0.03, (in region 2) (N. Al Ula and Az Zabirah) are 12.50, 10.05, 1.01, 1.19, 0.04 respectively. Classifications of sandstone depend on the content of these elements. These results are important for the safety of dwellers and user of sandstone in constructions.展开更多
A new digital logarithmic airborne gamma ray spectrometer is designed in this study. The spectrometer adopts a high-speed and high-accuracy logarithmic amplifier （LOGll4） to amplify the pulse signal logarithmically ...A new digital logarithmic airborne gamma ray spectrometer is designed in this study. The spectrometer adopts a high-speed and high-accuracy logarithmic amplifier （LOGll4） to amplify the pulse signal logarithmically and to improve the utilization of the ADC dynamic range because the low-energy pulse signal has a larger gain than the high-energy pulse signal. After energy calibration, the spectrometer can clearly distinguish photopeaks at 239, 352, 583 and 609 keV in the low-energy spectral sections. The photopeak energy resolution of 137Cs improves to 6.75% from the original 7.8%. Furthermore, the energy resolution of three photopeaks, namely, K, U, and Th, is maintained, and the overall stability of the energy spectrum is increased through potassium peak spectrum stabilization. Thus, it is possible to effectively measure energy from 20 keV to 10 MeV.展开更多
文摘The multiple nuclides identification algorithm with low consumption and strong robustness is crucial for rapid radioactive source searching.This study investigates the design of a low-consumption multiple nuclides identification algorithm for portable gamma spectrometers.First,the gamma spectra of 12 target nuclides(including the background case)were measured to create training datasets.The characteristic energies,obtained through energy calibration and full-energy peak addresses,are utilized as input features for a neural network.A large number of single-and multiple-nuclide training datasets are generated using random combinations and small-range drifting.Subsequently,a multi-label classification neural network based on a binary cross-entropy loss function is applied to export the existence probability of certain nuclides.The designed algorithm effectively reduces the computation time and storage space required by the neural network and has been successfully implemented in a portable gamma spectrometer with a running time of t_(r)<2 s.Results show that,in both validation and actual tests,the identification accuracy of the designed algorithm reaches 94.8%,for gamma spectra with a dose rate of d≈0.5μSv∕h and a measurement time t_(m)=60 s.This improves the ability to perform rapid on-site nuclide identification at important sites.
基金supported by the State Administration for Market Regulation Innovation Talent Program(No.QNBJ202304)Shanghai Municipal Health Commission(No.GWVI-11.1-40)Science and Technology Program of the Shanghai Municipal Administration for Market Regulation,(No.2022–07),China.
文摘Objective:To assess the detection efficiencies of liquid radioisotopes in a well-type NaI(Tl)gamma spectrometer,focusing on the short-lived isotopes^(99)Tcm,^(131)I,and^(18)F.Methods:The detection efficiencies of liquid 99Tcm,131I,and 18F in a well-type NaI(Tl)gamma spectrometer were systematically investigated through calibration experiments and Monte Carlo simulations,and accounting for the coincidence-summing effect.Results:The results indicated that the detection efficiencies of^(99)Tcm,^(131)I,and^(18)F varied from 64.4%to 72.3%,34.8%-43.1%and 27.3%-28.5%for different sample volumes ranging from 15 mL to 80 mL,respectively.The simulated detection efficiencies were highly consistent with the experimental results,with a largest relative deviation of 5%for the 3 radionuclides and 4 different sample volumes.Conclusion:The consistent results between the calibration experiments and Monte Carlo simulations reveal that this measuring device possesses high detection efficiencies of 99Tcm,131I,and 18F,making it suitable for measuring low-level activity radioactive liquids,such as radioactive waste liquids to be discharged.
基金partially supported by the National Natural Science Foundation of China(No.11775053).
文摘Iodine-131 is a highly toxic and volatile artificial radionuclide that is easily inhaled or ingested by the human body and selectively accumulates in thyroid tissue.With the development of nuclear medicine and nuclear power plants,the unintended release of ^(131)I has been widely studied,and the in vivo measurement of ^(131)I in the thyroid has become a research hotspot in the field of radiation protection.In recent decades,several methods and devices have been developed for in vivo measurements with respect to different measurement purposes and requirements.In this work,for more accurate determinations of individual ^(131)I in the thyroid in the field,the uncertainties of measurements by using portable gamma spectrometers were reviewed and analyzed,and monitoring strategies for improving the accuracy were proposed and prospected.
文摘The measurement principle and analysis method of natural gamma-ray spectra using Nal(T1) scintillation spectrometer are briefly described first, thed block diagrams of the HD-8004 Nal(T1) gamma-ray spectrometer. Finally, sample measurements are listed and discussed. The results are quite promising. Based on the analysis of these measurements, measures to improve the accuracy of spectrum measurement are proposed. It is well hoped that these measures call contribute to the development and application of gamma-ray spectrum measurement.
基金the National Science Foundation of China(No.41774147)the National Key R&D Program of China(No.2017YFC0602105)+1 种基金the Science–Technology Support Plan Projects of Sichuan Province(No.2020YJ0334)the Sichuan Science and Technology Program(No.2020JDRC0108).
文摘This paper describes a low-cost and fast method to evaluate gross α and β^(-) radioactivities in natural water based on an online high-purity germanium detector gamma measurement system.The major gamma activities in natural water are provided by natural and artificial radionuclides such as ^(40) K,^(137)Cs,and radionuclides belonging to ^(238)U and ^(232)Th series.The main a emitters related to gamma emissions in natural water are ^(224)Ra(240.98 keV)and ^(226)Ra(186.21 keV),and the β^(-) emitters are ^(40) K(1460.85 keV),^(214)Bi(609.31 keV),^(208)Tl(583.19 keV),and ^(214)Pb(351.93 keV).The formula for gross α and β^(-) activity concentration is based on these radionuclides,and the short half-life decay products are considered in the calculation.The detection efficiency of the device across energy region(0–3 MeV)is obtained through Monte Carlo simulation,and a calibration experiment is conducted to verify the simulation results.Gamma radioactivity is measured continuously for 114 d in Pixian County and Dongfeng Canal located in the Zouma River,Chengdu,Sichuan Province,China.A comparison of the calculation results and monitoring data from the Sichuan Management and Monitoring Center Station of Radioactive Environment indicates that the percentage and absolute error of a activity concentration is lower than 53%and 0.02 Bq/L,respectively,and that of β-activity concentration is lower than 33.2%and 0.016 Bq/L,respectively.The method can rapidly determine gross α and β^(-) activity concentrations in natural water online.
文摘Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.
文摘The activity concentrations of natural radionuclides <sup>226</sup>Ra, <sup>232</sup>Th and <sup>40</sup>K, were measured in (16) sandstone samples collected from two regions of Saudi Arabia, Region 1 (Al Wajh on Red Sea coast and Al Ula north-East of Medina), Region 2 (North of Al Ula and Az Zabirah, North-West of Hail) by (HPGe gamma spectrometer). The activity concentration average values of the radionuclides <sup>226</sup>Ra, <sup>232</sup>Th, and <sup>40</sup>K in the sandstone samples (Region 1) ranged from 10.97 ± 0.43, 27.68 ± 0.37 and 64.56 ± 0.74 Bq/kg respectively. These values are less than the international values reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR, 2000), in (Region 2), average values ranged from 2465.49 ± 0.00, 2042.00 ± 0.00 and 2259.65 ± 0.64 Bq/kg respectively. These values are higher than the values reported by (UNSCEAR, 2000). Average values of radium equivalent activity Ra<sub>eq</sub> (Bq/Kg), absorbed dose rate D (nGy/h), annual effective radiation dose D<sub>eff</sub> (mSv/y), External index (H<sub>ex</sub>) and Internal index (H<sub>in</sub>) were in (region 1) 21.13, 27.22, 11.75, 0.07 and 0.10 respectively, in (region 2) 5775.19, 1787.78, 846.58, 11.57 and 15.64 respectively. These results are lower (except annual effective radiation dose) in (region 1) and higher in (region 2) than the world recommended values by (UNSCEAR, 2000). Also, samples were analyzed by Atomic Absorption spectrometer (AAS) for Al, Ca, Fe, K, Mg and Bi in % elements concentrations. Average value in (region 1) (Al Wajh and Al Ula) are 4.42, 0.41, 1.37, 0.04 and 0.03, (in region 2) (N. Al Ula and Az Zabirah) are 12.50, 10.05, 1.01, 1.19, 0.04 respectively. Classifications of sandstone depend on the content of these elements. These results are important for the safety of dwellers and user of sandstone in constructions.
基金Supported by National Natural Science Foundation of China(40904054)National High Technology Research and Development Program 863(2012AA061803)
文摘A new digital logarithmic airborne gamma ray spectrometer is designed in this study. The spectrometer adopts a high-speed and high-accuracy logarithmic amplifier （LOGll4） to amplify the pulse signal logarithmically and to improve the utilization of the ADC dynamic range because the low-energy pulse signal has a larger gain than the high-energy pulse signal. After energy calibration, the spectrometer can clearly distinguish photopeaks at 239, 352, 583 and 609 keV in the low-energy spectral sections. The photopeak energy resolution of 137Cs improves to 6.75% from the original 7.8%. Furthermore, the energy resolution of three photopeaks, namely, K, U, and Th, is maintained, and the overall stability of the energy spectrum is increased through potassium peak spectrum stabilization. Thus, it is possible to effectively measure energy from 20 keV to 10 MeV.
