Cross-sections of the(n,2n) reactions for neodymium(Nd) isotopes induced by 14 MeV neutrons were measured in this work by using the activation and relative methods. The measured cross-sections of the ^(150)Nd(n,2n)^(1...Cross-sections of the(n,2n) reactions for neodymium(Nd) isotopes induced by 14 MeV neutrons were measured in this work by using the activation and relative methods. The measured cross-sections of the ^(150)Nd(n,2n)^(149)Nd,^(148)Nd(n,2n)^(147)Nd, and ^(142)Nd(n,2 n)^(141)Nd reactions were 1854 ± 81, 1789 ± 119, and 1559 ± 98 mb, respectively, at a neutron energy of 14.2 ± 0.2 MeV,and 1485 ± 74, 1726 ± 85, and 1670 ± 119 mb, respectively, at 14.9 ± 0.2 MeV. The results were compared with the experimental values from the reported literature, with the evaluated data from the ENDF/B-VII.1, CENDL-3.1, and JENDL-4.0 libraries, and with the curves calculated by the Talys-1.8 code.展开更多
Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)C...Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,serve as burnup monitors,assessing the number of fissions induced by neutrons on ^(235)U.However,current experimental data for these fission products worldwide are inconsistent,introducing significant uncertainty into related scientific research.In this study,we employed the Potential-driving Model to calculate the independent yields of ^(235)U and evaluate its advantages in such calculations.Additionally,we investigated the energy dependence of independent yields to select important products.Furthermore,we calculated the cumulative yields of ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,and compared them with existing literature data to explore the energy dependence of fission products for ^(235)U.Given the lack of fission product yield data above 14.8 MeV,we extended our calculated incident neutron energy to 20 MeV,aiming to support future scientific research.The Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments;thus,we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al.,which effectively describes the experimental data of the average total kinetic energy of fragments formed in ^(235)U fission.In this paper,we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.展开更多
Irradiation breeding is an important technique in the effort to solve food shortages and improve the quality of agricultural products.In this study,a field test was implemented on the M3 generation of two mutant pea p...Irradiation breeding is an important technique in the effort to solve food shortages and improve the quality of agricultural products.In this study,a field test was implemented on the M3 generation of two mutant pea plants gained from previous neutron radiation of pea seeds.The relationship between agronomic characteristics and yields of the mutants was investigated.Moreover,differences in physiological and biochemical properties and seed nutrients were analyzed.The results demonstrated that the plant height,effective pods per plant,and yield per plant of mutant Leaf-M1 were 45.0%,43.2%,and 50.9%higher than those of the control group,respectively.Further analysis attributed the increase in yield per plant to the increased branching number.The yield per plant of mutant Leaf-M2 was 7.8%higher than that of the control group,which could be related to the increased chlorophyll content in the leaves.There was a significant difference between the two mutants in the increase in yield per plant owing to morphological variation between the two mutants.There were significant differences in SOD activity and MDA content between the two mutants and the control,indicating that the physiological regulation of the two mutants also changed.In addition,the iron element content of seeds of the two mutants was about 10.9%lower than in the seeds of the control group,a significant difference.These findings indicate that the mutants Leaf-M1 and Leaf-M2 have breeding value and material value for molecular biological studies.展开更多
A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During...A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study,an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is >204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion(D_1^+,D_2^+, and D_3^+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.展开更多
We irradiated pea seeds with neutrons from a ^(252)Cf source and studied the radiation dose effects on various morphological development parameters during the growth of M_(1) generation peas.We found that in the dose ...We irradiated pea seeds with neutrons from a ^(252)Cf source and studied the radiation dose effects on various morphological development parameters during the growth of M_(1) generation peas.We found that in the dose range of 0.51-9.27 Gy,with the increase in neutron-absorbed dose,the morphological development parameters of M_(1) generation peas at the initial seedling stage showed an obvious trend with three fluctuations.With the development of pea,this trend gradually weakened.Further analysis and verification showed that the main trend in the M_(1) generation of pea seeds was an inhibitory effect induced by neutron irradiation and there was a good linear correlation between the inhibitory effect and neutron absorption dose We successfully demonstrated the background removal of mutant plants and defined morphological developmen parameters for peas that match the overall development of plants.Our results will positively impact neutron mutation breeding and automatic agriculture.展开更多
The potential-driving model is used to describe the driving potential distribution and to calculate the preneutron emission mass distributions for different incident energies in the 237 Np(n, f)reaction. The potential...The potential-driving model is used to describe the driving potential distribution and to calculate the preneutron emission mass distributions for different incident energies in the 237 Np(n, f)reaction. The potential-driving model is implemented in Geant4 and used to calculate the fission-fragment yield distributions, kinetic energy distributions, fission neutron spectrum and the total nubar for the 237 Np(n, f)reaction. Compared with the built-in G4 ParaFissionModel, the calculated results from the potential-driving model are in better agreement with the experimental data and evaluated data. Given the good agreement with the experimental data, the potential-driving model in Geant4 can describe well the neutron-induced fission of actinide nuclei, which is very important for the study of neutron transmutation physics and the design of a transmutation system.展开更多
Novel measurements of the neutron energy spectra of the 9Be(d,n)10B reaction with a thick beryllium target are performed using a fast neutron time-of-flight(TOF)spectrometer for the neutron emission angles θ=0°a...Novel measurements of the neutron energy spectra of the 9Be(d,n)10B reaction with a thick beryllium target are performed using a fast neutron time-of-flight(TOF)spectrometer for the neutron emission angles θ=0°and 45°,and the incident deuteron energies are 250 and 300 keV,respectively.The neutron contributions from the 9Be(d,n)10B reaction are distributed relatively independently for the ground state and the first,second,and third excited states of 10B.The branching ratios of the 9Be(d,n)10B reaction for the different excited states of 10B are obtained for the neutron emission angles θ=0°and 45°,and the incident deuteron energies are 250 and 300 keV,respectively.The branching ratio of the 9Be(d,n)10B reaction for the third excited state decreases with increase in the incident deuteron energy,and the branching ratios for the ground state and the second excited state increase with increase in the neutron emission angle.展开更多
The scission point model is improved by considering the excitation-dependent liquid drop model to calculate mass distributions for neutron-induced actinide nuclei fission.Excitation energy effects influence the deform...The scission point model is improved by considering the excitation-dependent liquid drop model to calculate mass distributions for neutron-induced actinide nuclei fission.Excitation energy effects influence the deformations of light and heavy fragments.The improved scission point model shows a significant advance with regard to accuracy for calculating pre-neutron-emission mass distributions of neutron-induced typical actinide fission with incident-neutron-energies up to 99.5 MeV.The theoretical frame assures that the improved scission point model is suitable for evaluating the fission fragment mass distributions,which will provide guidance for studying fission physics and designing nuclear fission engineering and nuclear transmutation systems.展开更多
文摘Cross-sections of the(n,2n) reactions for neodymium(Nd) isotopes induced by 14 MeV neutrons were measured in this work by using the activation and relative methods. The measured cross-sections of the ^(150)Nd(n,2n)^(149)Nd,^(148)Nd(n,2n)^(147)Nd, and ^(142)Nd(n,2 n)^(141)Nd reactions were 1854 ± 81, 1789 ± 119, and 1559 ± 98 mb, respectively, at a neutron energy of 14.2 ± 0.2 MeV,and 1485 ± 74, 1726 ± 85, and 1670 ± 119 mb, respectively, at 14.9 ± 0.2 MeV. The results were compared with the experimental values from the reported literature, with the evaluated data from the ENDF/B-VII.1, CENDL-3.1, and JENDL-4.0 libraries, and with the curves calculated by the Talys-1.8 code.
基金Supported by the National Natural Science Foundation of China(12075105)the NSFC-Nuclear Technology Innovation Joint Fund(U2167203)+1 种基金the Major Science and Technology Projects of Gansu Province(22ZD6GB020)the Fundamental Research Funds for the Central Universities of China(lzujbky-2022-ey14,Izujbky-2022-kb07)。
文摘Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices.Certain fission products,such as ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,serve as burnup monitors,assessing the number of fissions induced by neutrons on ^(235)U.However,current experimental data for these fission products worldwide are inconsistent,introducing significant uncertainty into related scientific research.In this study,we employed the Potential-driving Model to calculate the independent yields of ^(235)U and evaluate its advantages in such calculations.Additionally,we investigated the energy dependence of independent yields to select important products.Furthermore,we calculated the cumulative yields of ^(95)Zr,^(99)Mo,^(140)Ba,^(144)Ce,and ^(147)Nd,and compared them with existing literature data to explore the energy dependence of fission products for ^(235)U.Given the lack of fission product yield data above 14.8 MeV,we extended our calculated incident neutron energy to 20 MeV,aiming to support future scientific research.The Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments;thus,we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al.,which effectively describes the experimental data of the average total kinetic energy of fragments formed in ^(235)U fission.In this paper,we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.
基金supported by the National Natural Science Foundation of China(No.11675069)the Fundamental Research Funds for the Central Universities of China(No.lzujbky-2019-kb09)。
文摘Irradiation breeding is an important technique in the effort to solve food shortages and improve the quality of agricultural products.In this study,a field test was implemented on the M3 generation of two mutant pea plants gained from previous neutron radiation of pea seeds.The relationship between agronomic characteristics and yields of the mutants was investigated.Moreover,differences in physiological and biochemical properties and seed nutrients were analyzed.The results demonstrated that the plant height,effective pods per plant,and yield per plant of mutant Leaf-M1 were 45.0%,43.2%,and 50.9%higher than those of the control group,respectively.Further analysis attributed the increase in yield per plant to the increased branching number.The yield per plant of mutant Leaf-M2 was 7.8%higher than that of the control group,which could be related to the increased chlorophyll content in the leaves.There was a significant difference between the two mutants in the increase in yield per plant owing to morphological variation between the two mutants.There were significant differences in SOD activity and MDA content between the two mutants and the control,indicating that the physiological regulation of the two mutants also changed.In addition,the iron element content of seeds of the two mutants was about 10.9%lower than in the seeds of the control group,a significant difference.These findings indicate that the mutants Leaf-M1 and Leaf-M2 have breeding value and material value for molecular biological studies.
基金supported by the National Key Scientific Instrument and Equipment Development Project of China(2013YQ40861)the National Natural Science Foundations of China(11875155,11705071)the Fundamental Research Funds for the Central Universities of China(lzujbky-2019-kb09)
文摘A compact D–D neutron generator, with a peak neutron yield of D–D reactions up to 2.48×10~8 n/s is being developed at Lanzhou University in China for application in real-time neutron activation analysis. During tests, the problem of back acceleration of secondary electrons liberated from the neutron production target by deuterium ions bombardment was encountered. In this study,an electric field method and a magnetic field method for suppressing secondary electrons are designed and experimentally investigated. The experimental results show that the electric field method is superior to the magnetic field method. Effective suppression of the secondary electrons can be achieved via electrostatic suppression when the bias voltage between the target and the extraction-accelerating electrode is >204 V. Furthermore, the secondary electron emission coefficient for the mixed deuterium ion(D_1^+,D_2^+, and D_3^+) impacting on molybdenum is estimated. In the deuterium energy range of 80–120 keV, the estimated secondary electron emission coefficients are approximately 5–5.5 for the mixed deuterium ion glancing incidence of 45° and approximately 3.5–3.9 for the mixed deuterium ion normal incidence.
基金supported by the National Natural Science Foundation of China(Nos.11675069 and 12075106)the Natural Science Foundation of Gansu Province(No.20JR10RA607)the Fundamental Research Funds for the Central Universities of China(No.lzujbky-2020-kb09)。
文摘We irradiated pea seeds with neutrons from a ^(252)Cf source and studied the radiation dose effects on various morphological development parameters during the growth of M_(1) generation peas.We found that in the dose range of 0.51-9.27 Gy,with the increase in neutron-absorbed dose,the morphological development parameters of M_(1) generation peas at the initial seedling stage showed an obvious trend with three fluctuations.With the development of pea,this trend gradually weakened.Further analysis and verification showed that the main trend in the M_(1) generation of pea seeds was an inhibitory effect induced by neutron irradiation and there was a good linear correlation between the inhibitory effect and neutron absorption dose We successfully demonstrated the background removal of mutant plants and defined morphological developmen parameters for peas that match the overall development of plants.Our results will positively impact neutron mutation breeding and automatic agriculture.
基金Supported by the National Natural Science Foundation of China(11705071,11875155,11675069,21327801)NSAF(U1830102)+2 种基金NSFC-Nuclear Technology Innovation Joint Fund(U1867213)the DSTI Foundation of Gansu(2018ZX-07)the Fundamental Research Funds for the Central Universities(lzujbky-2017-13,lzujbky-2018-bt09,lzujbky-2019-bt09)
文摘The potential-driving model is used to describe the driving potential distribution and to calculate the preneutron emission mass distributions for different incident energies in the 237 Np(n, f)reaction. The potential-driving model is implemented in Geant4 and used to calculate the fission-fragment yield distributions, kinetic energy distributions, fission neutron spectrum and the total nubar for the 237 Np(n, f)reaction. Compared with the built-in G4 ParaFissionModel, the calculated results from the potential-driving model are in better agreement with the experimental data and evaluated data. Given the good agreement with the experimental data, the potential-driving model in Geant4 can describe well the neutron-induced fission of actinide nuclei, which is very important for the study of neutron transmutation physics and the design of a transmutation system.
基金Supported by the National Natural Science Foundation of China(11875155,11705071.12075105)the NSFC-Nuclear Technology Innovation Joint Fund(U1867213),the NSAF(U1830102)+1 种基金the Fundamental Research Funds for the Central Universities of China(zujbky-2020-kb09)the Projet of National Defense Science and Technology Industry for Nuclear Power Technology Inovation Center(HDLCXZX-2019-HD-33)。
文摘Novel measurements of the neutron energy spectra of the 9Be(d,n)10B reaction with a thick beryllium target are performed using a fast neutron time-of-flight(TOF)spectrometer for the neutron emission angles θ=0°and 45°,and the incident deuteron energies are 250 and 300 keV,respectively.The neutron contributions from the 9Be(d,n)10B reaction are distributed relatively independently for the ground state and the first,second,and third excited states of 10B.The branching ratios of the 9Be(d,n)10B reaction for the different excited states of 10B are obtained for the neutron emission angles θ=0°and 45°,and the incident deuteron energies are 250 and 300 keV,respectively.The branching ratio of the 9Be(d,n)10B reaction for the third excited state decreases with increase in the incident deuteron energy,and the branching ratios for the ground state and the second excited state increase with increase in the neutron emission angle.
基金the NSFC-Nuclear Technology Innovation Joint Fund(U1867213)the NSAF(U1830102)+1 种基金the National Natural Science Foundations of China(12075105,11705071,11875155)the Fundamental Research Funds for the Central Universities(lzujbky-2021-kb09)。
文摘The scission point model is improved by considering the excitation-dependent liquid drop model to calculate mass distributions for neutron-induced actinide nuclei fission.Excitation energy effects influence the deformations of light and heavy fragments.The improved scission point model shows a significant advance with regard to accuracy for calculating pre-neutron-emission mass distributions of neutron-induced typical actinide fission with incident-neutron-energies up to 99.5 MeV.The theoretical frame assures that the improved scission point model is suitable for evaluating the fission fragment mass distributions,which will provide guidance for studying fission physics and designing nuclear fission engineering and nuclear transmutation systems.
