scholarly journals The 4-dimensional Langevin approach to low energy nuclear fission

2018 ◽  
Vol 169 ◽  
pp. 00005
Author(s):  
F.A. Ivanyuk ◽  
C. Ishizuka ◽  
M.D. Usang ◽  
S. Chiba
Keyword(s):  
Excitation Energy ◽  
Mass Number ◽  
Nuclear Fission ◽  
Deformation Energy ◽  
Low Energy ◽  
Tooth Structure ◽  
Fission Fragments ◽  
Langevin Approach ◽  
Intrinsic Excitation ◽  
Mother Nucleus

We applied the four-dimensional Langevin approach to the description of fission of 235U by neutrons and calculated the dependence of the excitation energy of fission fragments on their mass number. For this we have fitted the compact just-before-scission configuration obtained by the Langevin calculations by the two separated fragments and calculated the intrinsic excitation and the deformation energy of each fragment accurately taking into account the shell and pairing effects and their dependence on the temperature and mass of the fragments. For the sharing of energy between the fission fragments we have used the simplest and most reliable assumption - the temperature of each fragment immediately after the neck rupture is the same as the temperature of mother nucleus just before scission. The calculated excitation energy of fission fragments clearly demonstrates the saw-tooth structure in the dependence on fragment mass number.

scholarly journals The description of the excitation energy sharing in nuclear fission within the Langevin approach

2021 ◽  
Vol 256 ◽  
pp. 00007
Author(s):  
F.A. Ivanyuk ◽  
S. Chiba
Keyword(s):  
Excitation Energy ◽  
Mass Number ◽  
Nuclear Fission ◽  
Deformation Energy ◽  
Langevin Equations ◽  
Excitation Energies ◽  
Tooth Structure ◽  
Fission Fragments ◽  
Langevin Approach ◽  
Energy Sharing

We apply the four-dimensional Langevin approach to the description of fission of 235U by neutrons and calculate the dependence of the excitation energy of fission fragments on their mass number. For this we run the Langevin equations until the compound nucleus splits into two separated fragments. This is possible since the we used in this work two-center shell model shape parametrization that describes well both compact and separated shapes. The excitation energies of each fragment are calculated assuming that the temperatures of both fragments are the same. The deformation energy of the fragment immediately after scission is added to its excitation energy. The saw-tooth structure of the dependence neutron multiplicity on the fragment’s mass number in reaction 235U + n at En = 5 Mev is qualitatively reproduced.

scholarly journals Impact of nuclear inertia momenta on fission observables

2018 ◽  
Vol 193 ◽  
pp. 01004
Author(s):  
P. Tamagno ◽  
O. Litaize
Keyword(s):  
Rigid Body ◽  
Excitation Energy ◽  
Nuclear Fission ◽  
Particle Model ◽  
Rotational Inertia ◽  
Neutron Fission ◽  
Fission Fragments ◽  
Rigid Body Model ◽  
Two Parameters ◽  
The Impact

Fission is probably the nuclear process the less accurately described with current models because it involves dynamics of nuclear matter with strongly coupled manybody interactions. It is thus diffcult to find models that are strongly rooted in good physics, accurate enough to reproduce target observables and that can describe many of the nuclear fission observables in a consistent way. One of the most comprehensive current modeling of the fission process relies on the fission sampling and Monte-Carlo de-excitation of the fission fragments. This model is implemented for instance in the FIFRELIN code. In this model fission fragments and their state are first sampled from pre-neutron fission yields, angular momentum distribution and excitation energy repartition law then the decay of both initial fragments is simulated. This modeling provides many observables: prompt neutron and gamma fission spectra, multiplicities and also fine decompositions: number of neutrons emitted as a function of the fragment mass, spectra per fragments, etc. This model relies on nuclear structure databases and on several basic nuclear models describing for instance gamma strength functions or level densities. Additionally some free parameters are still to be determined, namely two parameters describing the excitation energy repartition law, the spin cutoff of the heavy and light fragments and a rescaling parameter for the rotational inertia momentum of the fragments with respect of the rigid-body model. In the present work we investigate the impact of this latter parameter. For this we mainly substitute the corrected rigid-body value by a quantity obtained from a microscopic description of the fission fragment. The independent-particle model recently implemented in the CONRAD code is used to provide nucleonic wave functions that are required to compute inertia momenta with an Inglis-Belyaev cranking model. The impact of this substitution is analyzed on different fission observables provided by the FIFRELIN code.

scholarly journals Four-dimensional Langevin approach to low-energy nuclear fission of U236

2017 ◽  
Vol 96 (6) ◽  
Author(s):  
Chikako Ishizuka ◽  
Mark D. Usang ◽  
Fedir A. Ivanyuk ◽  
Joachim A. Maruhn ◽  
Katsuhisa Nishio ◽  
...  
Keyword(s):  
Nuclear Fission ◽  
Low Energy ◽  
Langevin Approach

The excitation energy of fragments in nuclear fission

Atomic Energy ◽  
1960 ◽  
Vol 6 (3) ◽  
pp. 184-189
Author(s):  
B. T. Geilikman
Keyword(s):  
Excitation Energy ◽  
Nuclear Fission

On Z=2 Projectile Fragments Emitted in the Interactions of 3.7A GeV 28Si in Nuclear Emulsions

1998 ◽  
Vol 07 (03) ◽  
pp. 341-355 ◽  
Author(s):  
B. K. Singh ◽  
S. K. Tuli
Keyword(s):  
Excitation Energy ◽  
Cross Sections ◽  
Mass Number ◽  
Multiplicity Distribution ◽  
Production Cross ◽  
Emission Angle ◽  
Single Source ◽  
Momentum Spread ◽  
Nuclear Emulsions ◽  
Scaling Behaviour

We report the results on partial production cross sections for Z=2 projectile fragments emitted in 28Si-emulsion interactions at 3.7 A GeV. Scaling behaviour of the multiplicity distribution of Z=2 PFs has been checked. The emission angle of Z=2 PFs has been measured and pseudorapidity distributions for these PFs have been obtained. We observe that the value of momentum spread σ(p) for Z=2 PFs grows with increasing mass number of the projectile. The emission of Z=2 PFs is consistent with a single source with an excitation energy of about 8.9 MeV. The data has been compared with available data reported for lighter as well as heavier projectiles at the same and/or different energies.

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