Research on neutron-induced fission product yields of^(232)Th is crucial for understanding the competition between symmetric and asymmetric fission in actinide nuclei.However,obtaining complete isotopic yield distribu...Research on neutron-induced fission product yields of^(232)Th is crucial for understanding the competition between symmetric and asymmetric fission in actinide nuclei.However,obtaining complete isotopic yield distributions over a wide range of neutron energies remains a challenge.In this study,a Bayesian neural network model was developed to predict the independent(IND)and cumulative fission yields of^(232)Th under neutron irradiation at various incident energies.To address the limited availability of experimental data for the analysis of IND mass distributions,we substituted mass-number-based yields with the yields of specific isotopes.Furthermore,physical phenomena or quantities,such as the odd-even effect and isospin,were introduced as constraints to enhance the physical consistency of the predictions.The impact of these constraints was evaluated using mass-chain yield distributions and their dependence on energy.Incorporating physical constraints significantly improves the prediction accuracy,yielding more reliable and physically meaningful fission yield data for nuclear physics and reactor design applications.展开更多
为在γ放射性活度很大的测量中使测量系统得到更好的准确度，本文使用干扰源研究 HPGe探测器得到了测量系统死时间与计数损失的关系。在γ能量为0.3～1.3 M eV 时进行实验，使用10^4～10^5 Bq量级的放射源，修正能峰的计数率一般保持在...为在γ放射性活度很大的测量中使测量系统得到更好的准确度，本文使用干扰源研究 HPGe探测器得到了测量系统死时间与计数损失的关系。在γ能量为0.3～1.3 M eV 时进行实验，使用10^4～10^5 Bq量级的放射源，修正能峰的计数率一般保持在几十s－1，证明在误差范围（3％）内，计数损失随死时间变化的关系与射线能量和计数强度无关，任意强度的任意核素均可使用这一修正公式进行计数损失修正。展开更多
文摘基于广义约化R矩阵理论,使用RAC程序(R-matrix analysis code)综合分析了^(6)He系统中所有可以利用的实验数据,给出了氚核入射10-2—20 MeV能量范围内主要反应道的评价核数据.其中积分截面包括T(t,2n)^(4)He,T(t,n)^(5)He,T(t,d)^(4)H;微分截面包括T(t,2n)^(4)He,T(t,n)^(5)He,T(t,d)^(4)H,T(t,t)T.结果表明,RAC的评价结果与实验数据和ENDF/B-Ⅷ.1的评价数据整体符合良好.重点关注T(t,2n)^(4)He反应,评价值在10^(-2)—20 MeV范围内与已有实验数据一致,在2.9 Me V附近出现由2+能级主导的共振,在1.9 Me V处,已有实验同时测量了积分截面和角分布,本工作的评价结果在两类数据上均表现出良好的一致性,积分截面与微分截面的联合约束有效提升了R矩阵参数的稳定性和评价结果的可靠性.基于6He系统的整体评价,进一步补充了T(t,n)^(5)He和T(t,d)^(4)H反应的截面数据.本工作完善了聚变反应相关的数据基础,并为后续与镜像系统6Be系统的联合分析奠定了基础.
基金supported by the National Natural Science Foundation of China(Nos.12247126 and 12375123)Henan Postdoctoral Foundation(No.HN2024013)the Natural Science Foundation of Henan Province(No.242300421048)。
文摘Research on neutron-induced fission product yields of^(232)Th is crucial for understanding the competition between symmetric and asymmetric fission in actinide nuclei.However,obtaining complete isotopic yield distributions over a wide range of neutron energies remains a challenge.In this study,a Bayesian neural network model was developed to predict the independent(IND)and cumulative fission yields of^(232)Th under neutron irradiation at various incident energies.To address the limited availability of experimental data for the analysis of IND mass distributions,we substituted mass-number-based yields with the yields of specific isotopes.Furthermore,physical phenomena or quantities,such as the odd-even effect and isospin,were introduced as constraints to enhance the physical consistency of the predictions.The impact of these constraints was evaluated using mass-chain yield distributions and their dependence on energy.Incorporating physical constraints significantly improves the prediction accuracy,yielding more reliable and physically meaningful fission yield data for nuclear physics and reactor design applications.
文摘为在γ放射性活度很大的测量中使测量系统得到更好的准确度，本文使用干扰源研究 HPGe探测器得到了测量系统死时间与计数损失的关系。在γ能量为0.3～1.3 M eV 时进行实验，使用10^4～10^5 Bq量级的放射源，修正能峰的计数率一般保持在几十s－1，证明在误差范围（3％）内，计数损失随死时间变化的关系与射线能量和计数强度无关，任意强度的任意核素均可使用这一修正公式进行计数损失修正。
