Fission properties of the actinide nuclei are deduced from theoretical analysis.We investigate potential energy surfaces and fission barriers and predict the fission fragment mass yields of actinide isotopes.The resul...Fission properties of the actinide nuclei are deduced from theoretical analysis.We investigate potential energy surfaces and fission barriers and predict the fission fragment mass yields of actinide isotopes.The results are compared with experimental data where available.The calculations were performed in the macroscopic-microscopic approximation With the Lublin-Strasbourg Drop(LSD)for the macroscopic part,and the microscopic energy corrections were evaluated in the Yukawa-folded potential.The Fourier nuclear shape parametrization is used to describe the nuclear shape,including the non-axial degree of freedom.The fission fragment mass yields of the nuclei considered are evaluated within a 3D colletive model using the Borm-Oppenheimer approximation.展开更多
Pre-neutron fragment mass yields in the vicinity of the thermal neutron energy are highly important for applications because of the larger fission cross sections of the^(235)U(n,f)and^(239)Pu(n,f)reactions.In this pap...Pre-neutron fragment mass yields in the vicinity of the thermal neutron energy are highly important for applications because of the larger fission cross sections of the^(235)U(n,f)and^(239)Pu(n,f)reactions.In this paper,preneutron fragment mass yields at incident energies from thermal up to 20 MeV are systematically studied using an empirical fission potential(EFP)model,the potential parameters of which are obtained from the measured data.The energy dependences of the peaks and valleys of the pre-neutron fragment mass yields are described by exponential and linear functions for the^(235)U(n,f)and^(239)Pu(n,f)reactions,respectively.The energy dependences of the evaporation neutrons,which play a crucial role in the reasonable description of pre-neutron fragment mass yields,are also obtained from the fission cross sections.The pre-neutron fragment mass yields in this study are not only consistent with the results of previous studies in regions of several Me Vs but also agree well with existing measured data at incident energies from thermal up to 20 MeV.The results show that the feasibility of this EFP model is verified in this extended energy region.展开更多
A simple approach is proposed to describe the experimental data for the widths of the fission-fragment mass yields in^(197)Au and^(209)Bi at low and intermediate energies.The approach is based on the expressions for t...A simple approach is proposed to describe the experimental data for the widths of the fission-fragment mass yields in^(197)Au and^(209)Bi at low and intermediate energies.The approach is based on the expressions for the temperature dependence of the width of the fission-fragment mass yield and the mass of the most probable fragment.The expression for the width of the fission-fragment mass yield depends on the mass of the most probable fragment,the surface terms of the energy level density parameter,the temperature and the stiffness parameter of the potential related to mass-asymmetric degree of freedom.It is shown that the contribution of the surface term of the energy level density parameter is important for describing the experimental data in a wide range of energies.展开更多
The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 ...The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 fm.The standard Gogny interactions g0,g0 as,and gOass were adopted in simulating the collisions at an impact parameter of b=0 fm.It was found,using an isobaric yield ratio method,that temperature of the primary fragment depends on the incident energy and hardness of the interaction potential.The temperature obtained in this work agrees with the results by the self-consistent fitting method.展开更多
Photofission fragments mass yield for^(232)Th,^(234;238) U,^(237) Np, and^(239;240;242) Pu isotopes are investigated.The calculations are done using a developed approach based on Gorodisskiy's phenomenological for...Photofission fragments mass yield for^(232)Th,^(234;238) U,^(237) Np, and^(239;240;242) Pu isotopes are investigated.The calculations are done using a developed approach based on Gorodisskiy's phenomenological formalism. The Gorodisskiy's method is developed to be applied for the neutron-induced fission. Here we revised it for application to photofission. The effect of emitted neutron prior to fission on the fission fragment mass yields has also been studied. The peak-to-valley ratio is extracted for the240 Pu isotope as a function of energy. Obtained results of the present formalism are compared with the available experimental data. Satisfactory agreement is achieved between the results of present approach and the experimental data.展开更多
A new statistical method for systematizing the nuclei fission fragments, investigation of their mass and charge spectra and neutron fission parameters has been suggested. In proposed method, the mass and charge yields...A new statistical method for systematizing the nuclei fission fragments, investigation of their mass and charge spectra and neutron fission parameters has been suggested. In proposed method, the mass and charge yields of nucleons are determined from the equilibrium conditions of the nuclear fragments post-fission ensemble. Here we consider protons and neutrons of different fragments as statistically non-equivalent. The abilities of the proposed statistical method for explanation of the U, Pa, Th, Ac and Ra post-fission fragments ordering and neutron emission function calculation have been demonstrated.展开更多
基金the Polish National Science Center(2018/30/Q/ST2/00185)the National Natural Science Foundaion of China(11961131010,11790325)。
文摘Fission properties of the actinide nuclei are deduced from theoretical analysis.We investigate potential energy surfaces and fission barriers and predict the fission fragment mass yields of actinide isotopes.The results are compared with experimental data where available.The calculations were performed in the macroscopic-microscopic approximation With the Lublin-Strasbourg Drop(LSD)for the macroscopic part,and the microscopic energy corrections were evaluated in the Yukawa-folded potential.The Fourier nuclear shape parametrization is used to describe the nuclear shape,including the non-axial degree of freedom.The fission fragment mass yields of the nuclei considered are evaluated within a 3D colletive model using the Borm-Oppenheimer approximation.
基金Supported by the National Natural Science Foundation of China(12065003)the Natural Science Foundation of Guangxi(2019GXNSFDA185011)+2 种基金the Key Laboratory of Neutron Physics China Academy of Engineering Physics(2018BA03)the Scientific Research and Technology Development Project of Guilin(20210104-2)the Central Government Guides Local Scientic and Technological Development Funds of China(Guike ZY22096024)。
文摘Pre-neutron fragment mass yields in the vicinity of the thermal neutron energy are highly important for applications because of the larger fission cross sections of the^(235)U(n,f)and^(239)Pu(n,f)reactions.In this paper,preneutron fragment mass yields at incident energies from thermal up to 20 MeV are systematically studied using an empirical fission potential(EFP)model,the potential parameters of which are obtained from the measured data.The energy dependences of the peaks and valleys of the pre-neutron fragment mass yields are described by exponential and linear functions for the^(235)U(n,f)and^(239)Pu(n,f)reactions,respectively.The energy dependences of the evaporation neutrons,which play a crucial role in the reasonable description of pre-neutron fragment mass yields,are also obtained from the fission cross sections.The pre-neutron fragment mass yields in this study are not only consistent with the results of previous studies in regions of several Me Vs but also agree well with existing measured data at incident energies from thermal up to 20 MeV.The results show that the feasibility of this EFP model is verified in this extended energy region.
文摘A simple approach is proposed to describe the experimental data for the widths of the fission-fragment mass yields in^(197)Au and^(209)Bi at low and intermediate energies.The approach is based on the expressions for the temperature dependence of the width of the fission-fragment mass yield and the mass of the most probable fragment.The expression for the width of the fission-fragment mass yield depends on the mass of the most probable fragment,the surface terms of the energy level density parameter,the temperature and the stiffness parameter of the potential related to mass-asymmetric degree of freedom.It is shown that the contribution of the surface term of the energy level density parameter is important for describing the experimental data in a wide range of energies.
基金supported by the Program for Science and Technology Innovation Talents in Universities of Henan Province(13HASTIT046)Henan Normal University for the Excellent Youth(154100510007)the support from the Creative Experimental Project of National Undergraduate Students(CEPNU201510476017)
文摘The primary fragments in ^(40)Ca +^(40)Ca reactions at 35,50,80,100,140,and 300 MeV/u were simulated using the antisymmetrized molecular dynamics model,in the phase space at t=300 fm/c with a coalescence radius R_c=5 fm.The standard Gogny interactions g0,g0 as,and gOass were adopted in simulating the collisions at an impact parameter of b=0 fm.It was found,using an isobaric yield ratio method,that temperature of the primary fragment depends on the incident energy and hardness of the interaction potential.The temperature obtained in this work agrees with the results by the self-consistent fitting method.
文摘Photofission fragments mass yield for^(232)Th,^(234;238) U,^(237) Np, and^(239;240;242) Pu isotopes are investigated.The calculations are done using a developed approach based on Gorodisskiy's phenomenological formalism. The Gorodisskiy's method is developed to be applied for the neutron-induced fission. Here we revised it for application to photofission. The effect of emitted neutron prior to fission on the fission fragment mass yields has also been studied. The peak-to-valley ratio is extracted for the240 Pu isotope as a function of energy. Obtained results of the present formalism are compared with the available experimental data. Satisfactory agreement is achieved between the results of present approach and the experimental data.
文摘A new statistical method for systematizing the nuclei fission fragments, investigation of their mass and charge spectra and neutron fission parameters has been suggested. In proposed method, the mass and charge yields of nucleons are determined from the equilibrium conditions of the nuclear fragments post-fission ensemble. Here we consider protons and neutrons of different fragments as statistically non-equivalent. The abilities of the proposed statistical method for explanation of the U, Pa, Th, Ac and Ra post-fission fragments ordering and neutron emission function calculation have been demonstrated.
