In scenarios such as vehicle radiation monitoring and unmanned aerial vehicle radiation detection,rapid measurements using a NaI(Tl)detector often result in low photon counts,weak characteristic peaks,and significant ...In scenarios such as vehicle radiation monitoring and unmanned aerial vehicle radiation detection,rapid measurements using a NaI(Tl)detector often result in low photon counts,weak characteristic peaks,and significant statistical fluctuations.These issues can lead to potential failures in peak-searching-based identification methods.To address the low precision associated with short-duration measurements of radionuclides,this paper proposes an identification algorithm that leverages heterogeneous spectral transfer to develop a low-count energy spectral identification model.Comparative experiments demonstrated that transferring samples from 26 classes of simulated heterogeneous gamma spectra aids in creating a reliable model for measured gamma spectra.With only 10%of target domain samples used for training,the accuracy on real low-count spectral samples was 95.56%.This performance shows a significant improvement over widely employed full-spectrum analysis methods trained on target domain samples.The proposed method also exhibits strong generalization capabilities,effectively mitigating overfitting issues in low-count energy spectral classification under short-duration measurements.展开更多
针对国内测量85Kr探测下限较高的现状,本文通过探测其衰变产生的β射线,设计并优化探测系统的本底和探测效率,实现对85Kr极低放射性浓度的测量。在探测器设计中,采用国产正比计数管作为4π主探测器,辅以铅铜屏蔽,以塑料闪烁体作为反符...针对国内测量85Kr探测下限较高的现状,本文通过探测其衰变产生的β射线,设计并优化探测系统的本底和探测效率,实现对85Kr极低放射性浓度的测量。在探测器设计中,采用国产正比计数管作为4π主探测器,辅以铅铜屏蔽,以塑料闪烁体作为反符合探测器。通过Geant4模拟研究正比计数管的探测效率,分析了其尺寸、工作气压对探测下限的影响,提出了优化方案。模拟结果表明,最佳的正比计数管参数为半径30 mm、长度100 mm,并在压强大于1 atm的条件下可有效提高探测效率至92%以上。塑料闪烁体反符合效率达90.29%,铅铜屏蔽厚度优化为外层8 cm、内层2 cm,屏蔽效率达99.5%。根据优化得到的主探测器的探测效率和探测系统的本底,计算出理论探测下限可达16.08 m Bq/m~3,比国内正比计数管的探测下限180 m Bq/m~3降低一个数量级。本研究为开发一种成本低、结构简单、性能可靠的^(85)Kr实时监测系统提供了重要的模拟参考和理论依据。展开更多
基金supported by the National Defense Fundamental Research Project(No.JCKY2022404C005)the Nuclear Energy Development Project(No.23ZG6106)+1 种基金the Sichuan Scientific and Technological Achievements Transfer and Transformation Demonstration Project(No.2023ZHCG0026)the Mianyang Applied Technology Research and Development Project(No.2021ZYZF1005)。
文摘In scenarios such as vehicle radiation monitoring and unmanned aerial vehicle radiation detection,rapid measurements using a NaI(Tl)detector often result in low photon counts,weak characteristic peaks,and significant statistical fluctuations.These issues can lead to potential failures in peak-searching-based identification methods.To address the low precision associated with short-duration measurements of radionuclides,this paper proposes an identification algorithm that leverages heterogeneous spectral transfer to develop a low-count energy spectral identification model.Comparative experiments demonstrated that transferring samples from 26 classes of simulated heterogeneous gamma spectra aids in creating a reliable model for measured gamma spectra.With only 10%of target domain samples used for training,the accuracy on real low-count spectral samples was 95.56%.This performance shows a significant improvement over widely employed full-spectrum analysis methods trained on target domain samples.The proposed method also exhibits strong generalization capabilities,effectively mitigating overfitting issues in low-count energy spectral classification under short-duration measurements.
文摘针对国内测量85Kr探测下限较高的现状,本文通过探测其衰变产生的β射线,设计并优化探测系统的本底和探测效率,实现对85Kr极低放射性浓度的测量。在探测器设计中,采用国产正比计数管作为4π主探测器,辅以铅铜屏蔽,以塑料闪烁体作为反符合探测器。通过Geant4模拟研究正比计数管的探测效率,分析了其尺寸、工作气压对探测下限的影响,提出了优化方案。模拟结果表明,最佳的正比计数管参数为半径30 mm、长度100 mm,并在压强大于1 atm的条件下可有效提高探测效率至92%以上。塑料闪烁体反符合效率达90.29%,铅铜屏蔽厚度优化为外层8 cm、内层2 cm,屏蔽效率达99.5%。根据优化得到的主探测器的探测效率和探测系统的本底,计算出理论探测下限可达16.08 m Bq/m~3,比国内正比计数管的探测下限180 m Bq/m~3降低一个数量级。本研究为开发一种成本低、结构简单、性能可靠的^(85)Kr实时监测系统提供了重要的模拟参考和理论依据。
