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
The radioisotope actinium-225(^(225)Ac)has been successfully used for targeted alpha therapy in preclinical and clinical applications because of its excellent nuclear characteristics.Medium-and high-energy proton-spal...The radioisotope actinium-225(^(225)Ac)has been successfully used for targeted alpha therapy in preclinical and clinical applications because of its excellent nuclear characteristics.Medium-and high-energy proton-spallation reactions on thorium are the most important methods for producing^(225)Ac.This study examines the possibility of producing^(225)Ac by irradiating thorium oxide with medium-energy protons.Thorium-oxide sheets were irradiated with 40-,50-,60-,70-,and 80-Me V protons on the Associated Proton-beam Experiment Platform(APEP)of the China Spallation Neutron Source(CSNS).The cross sections for the formation of^(225)Ac were measured using the activation method and offline gamma-ray spectrometric technique.The experimental results were compared with the existing data from EXFOR as well as the theoretical data from the TALYS-based evaluated nuclear-data library.Based on the experimental cross section and theoretical calculations,the production yield of^(225)Ac in the irradiated thorium targets was examined.The results showed that APEP can produce sufficient quantities of^(225)Ac for purification and clinical therapy.This work is the first measurement of proton-induced nuclearreaction cross sections at the CSNS APEP.展开更多
文摘国际照明委员会(CIE)近日通知,2026年向各国家委员会分发技术报告CIE 232:2019《Discomfort Caused by Glare from Luminaires with a Non-Uniform Source Luminance(灯具光源亮度不均引起不舒适眩光)》及其勘误表。
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.
文摘在第四代反应堆的发展中,钍基反应堆(例如钍基熔盐堆)是其中一个重要的研究方向.由于钍的储量大等因素,利用中子诱发^(232)Th发生辐射俘获反应产生^(233)Th是钍基反应堆中的一个重要反应,用于产生易裂变核素^(233)U.本研究采用Monte Carlo方法,定义了一种评价靶材和中子利用效率的综合利用系数,利用多项式拟合得到了综合利用系数和靶材厚度关系,并考虑了不同入射中子数目的影响,最后得到进行此反应的靶材最佳厚度为(1.980±0.002) cm.
基金supported by the National Natural Science Foundation of China(No.12075135)the National Natural Science Foundation of China(No.12375127)。
文摘The radioisotope actinium-225(^(225)Ac)has been successfully used for targeted alpha therapy in preclinical and clinical applications because of its excellent nuclear characteristics.Medium-and high-energy proton-spallation reactions on thorium are the most important methods for producing^(225)Ac.This study examines the possibility of producing^(225)Ac by irradiating thorium oxide with medium-energy protons.Thorium-oxide sheets were irradiated with 40-,50-,60-,70-,and 80-Me V protons on the Associated Proton-beam Experiment Platform(APEP)of the China Spallation Neutron Source(CSNS).The cross sections for the formation of^(225)Ac were measured using the activation method and offline gamma-ray spectrometric technique.The experimental results were compared with the existing data from EXFOR as well as the theoretical data from the TALYS-based evaluated nuclear-data library.Based on the experimental cross section and theoretical calculations,the production yield of^(225)Ac in the irradiated thorium targets was examined.The results showed that APEP can produce sufficient quantities of^(225)Ac for purification and clinical therapy.This work is the first measurement of proton-induced nuclearreaction cross sections at the CSNS APEP.
