Stochastic model of tilting mode in nuclear fission

Eremenko, D. O.; Drozdov, V. A.; Eslamizadex, M. H.; Fotina, O. V.; Platonov, S. Yu.; Yuminov, O. A.

doi:10.1134/s1063778806080229

Cited by 26 publications

(19 citation statements)

References 12 publications

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“…[19]. Such description is more consistent than the application of the Metropolis algorithm [20,21,49]. The Langevin equation for the K coordinate allows the modeling of the relaxation process of K states depending on the instantaneous physical properties of fissioning system such as temperature and moment of inertia instead of treating the corresponding relaxation time τ K as a free parameter [20][21][22].…”

Section: Modelmentioning

confidence: 99%

“…Finally, the quantities L c and δL were constrained from the experimental fusion cross section and L 2 . In the present study, we neglected the spins of projectile and target nuclei and assumed that the spin of the compound nucleus I L. The initial K value was generated using the Monte Carlo method from uniform distribution in the interval (−L, L) [19,20]. The initial conditions for the shape coordinates were chosen as follows.…”

Section: Modelmentioning

confidence: 99%

“…An alternative dynamical description of the evolution of the orientation degree of freedom on the basis of a Metropolis algorithm and an algorithm of Kubo-Anderson process was previously developed in Refs. [20][21][22]. This approach was successfully applied to describe fragment angular distributions from excited compound nuclei fission.…”

Section: Introductionmentioning

confidence: 98%

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Four-dimensional Langevin dynamics of heavy-ion-induced fission

et al. 2012

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A four-dimensional dynamical model based on Langevin equations was developed and applied to calculate a wide set of experimental observables for the reactions 16 O + 208 Pb → 224 Th and 16 O + 232 Th → 248 Cf over a wide range of excitation energy. The fusion-fission and evaporation residue cross sections, fission fragment mass-energy distribution parameters, prescission neutron multiplicities, and anisotropy of angular distribution of fission fragments could be reasonably reproduced using a modified one-body mechanism for nuclear friction with a reduction coefficient of the contribution from a wall formula k s 0.25 and a dissipation coefficient for the orientation degree of freedom (K coordinate) γ K 0.077 (MeV zs) −1/2 . Inclusion of the K coordinate into calculation of potential energy changes the stiffness of the nucleus with respect to mass asymmetry coordinate for the values of K = 0 and results in a shift of the Businaro-Gallone point towards larger Z 2 /A values. The experimental data on the fission fragment mass-energy distribution parameters together with mean prescission neutron multiplicity for heavy fissioning nuclei are reproduced through the four-dimensional Langevin calculations more accurately than through three-dimensional calculations.

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Section: Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

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Four-dimensional Langevin dynamics of heavy-ion-induced fission

et al. 2012

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“…They described the evolution of the coordinate K in terms of the Langevin equation in the overdamped mode. The Langevin equation for the coordinate K permits simulating the relaxation of K states with allowance for instantaneous physical properties of the fissioning system, such as its temperature and moment of inertia, instead of treating the respective relaxation time as a free parameter [9,10]; moreover, it describes the evolution of all collective degrees of freedom of the nucleus within a unified conceptual framework. Thus, the Langevin dynamics of fission induced by heavy ions must include at least four collective coordinates-three for the evolution of the nuclear shape [7,8] and one for the evolution of the K mode [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Eremenko and his coauthors [9,10] were the first who proposed considering the evolution of the orientation degree of freedom of the nucleus involved (K mode -that is, the projection of the total angular momentum I onto the symmetry axis of the nucleus) as an independent collective coordinate, relying on the Monte Carlo method implemented with the aid of an algorithm that simulates the Anderson-Kubo process. They were able to describe successfully the angular distributions of fission fragments and mean multiplicities of prescission neutrons for a number of fusion-fission reactions involving heavy ions.…”

Section: Introductionmentioning

confidence: 99%

Mass-energy distribution of fragments in Langevin dynamics of fission induced by heavy ions

Anischenko

Vanin

Адеев

2012

EPJ Web of Conferences

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Abstract. Four-dimensional Langevin equation was employed to calculate mass-energy distributions of fission fragments of highly excited compound nuclei. The research took into account not only three shape collective coordinates introduced on the basis of {c, h, α}-parametrization but also orientation degree of freedom (K-state) -spin about the symmetry axis. Overdamped Langevin equation was used to describe the evolution of the K-state. Friction tensor was calculated using the "wall+window" model of the modified one-body dissipation mechanism with a reduction coefficient from the "wall" formula k s . The calculations have been performed with k s = 0.25 and k s = 1.0. To learn more about the role of the dissipation effects the calculations have also been done with use of the chaoticity measure of nucleon movements in the nuclear shape configuration as k s parameter. Calculations were performed for the large number of compound nuclei with Z 2 /A parameter in the range 21 Z 2 /A 44. The goal was to study the mass-energy distributions not only for heavy nuclei but also for light nuclei close to the Businaro-Gallone point. Mass-energy distributions and variances of the mass fragments are well reproduced in the applied calculations for all considered compound nuclei. It was shown that inclusion of the K-state in the dynamical model produces considerable increase of the mass and energy variances. Inclusion of the chaoticity measure to the friction tensor provides a better agreement with the experiment results on mass variances.

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Investigation of fission fragments average spin based on four dimensional Langevin dynamical model

Naderi¹,

Salimi²

2017

Chinese Phys. C

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We applied the four dimensional Langevin dynamical model to investigate the average spin of fission fragments. Elongation, neck thickness, asymmetry parameter, and the orientation degree of freedom (K coordinate) are the four dimensions of the dynamical model. We assume that the collective modes depend on the emission angle of the fragments, then different parameters related to the average spin of fission fragments are calculated dynamically. The angle dependence of average spin of fission fragments is investigated by calculating the spin at angles 90° and 165°. Also, the obtained results based on the transition state model at scission point are presented. One can obtain better agreement between the results of the dynamical model and experimental data in comparison with the results of the transition state model.

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Stochastic model of tilting mode in nuclear fission

Cited by 26 publications

References 12 publications

Four-dimensional Langevin dynamics of heavy-ion-induced fission

Four-dimensional Langevin dynamics of heavy-ion-induced fission

Mass-energy distribution of fragments in Langevin dynamics of fission induced by heavy ions

Investigation of fission fragments average spin based on four dimensional Langevin dynamical model

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