Incorporation of a tilting coordinate into the multidimensional Langevin dynamics of heavy-ion-induced fission: Analysis of experimental data from fusion-fission reactions

Nadtochy, P. N.; Ryabov, E. G.; Gegechkori, A. E.; Anischenko, Yu. A.; Адеев, Г. Д.

doi:10.1103/physrevc.89.014616

Cited by 59 publications

(25 citation statements)

References 95 publications

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“…Most of the results obtained in these works seem compatible with presaddle reduced dissipation parameters between 2 and 6 × 10 21 s −1 , while the saddle-to-scission dynamics is better described by using larger values around 30 × 10 21 s −1 . However, these conclusions contradict recent results obtained with sophisticated Langevin calculations [25,29], where the value of the dissipation parameter slightly decreases with deformation.…”

contrasting

confidence: 89%

Presaddle and postsaddle dissipative effects in fission using complete kinematics measurements

et al. 2016

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International audienceA complete kinematics measurement of the two fission fragments was used for the first time to investigatefission dynamics at small and large deformations. Fissioning systems with high excitation energies, compactshapes, and low angular momenta were produced in inverse kinematics by using spallation reactions of leadprojectiles. A new generation experimental setup allowed for the first full and unambiguous identification inmass and atomic number of both fission fragments. This measurement permitted us to accurately determinefission cross sections, the charge distribution, and the neutron excess of the fission fragments as a function of theatomic number of the fissioning system. These data are compared with different model calculations to extractinformation on the value of the dissipation parameter at small and large deformations. The present results do notshow any sizable dependence of the nuclear dissipation parameter on temperature or deformation

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confidence: 89%

Presaddle and postsaddle dissipative effects in fission using complete kinematics measurements

et al. 2016

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“…Moreover, attempts for restraining the statistical-model parameters have also been reported [29]; however, a consistent description of the experimental data for all three observables, namely , fission, and ER excitation functions for shell closed nuclei, is yet to be achieved. In this direction, recent developments in multi-dimensional stochastic approaches have been fairly successful in describing the fission characteristics of excited nuclei [30][31][32][33][34][35]. However, a simultaneous description of the experimental data and a systematic study of shell closed nuclei are yet to be attempted.…”

Section: ≈ =mentioning

confidence: 99%

Investigating the fission dynamics of the following neutron shell closed nuclei within a stochastic dynamical approach: ²¹⁰Po, ²¹²Rn, and ²¹³Fr*

Arora¹,

Sugathan²,

Chatterjee³

2023

Chinese Phys. C

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Dissipative dynamics of nuclear fission is a well confirmed phenomenon described either by a Kramers-modified statistical model or by a dynamical model employing the Langevin equation. Though dynamical models as well as statistical models incorporating fission delay are found to explain the measured fission observables in many studies, it nonetheless shows conflicting results for shell closed nuclei in the mass region 200. Analysis of recent data for neutron shell closed nuclei in excitation energy range 40−80 MeV failed to arrive at a satisfactory description of the data and attributed the mismatch to shell effects and/or entrance channel effects, without reaching a definite conclusion. In the present work we show that a well established stochastic dynamical code simultaneously reproduces the available data of pre-scission neutron multiplicities, fission and evaporation residue excitation functions for neutron shell closed nuclei 210Po and 212Rn and their isotopes 206Po and 214,216Rn without the need for including any extra shell or entrance channel effects. The calculations are performed by using a phenomenological universal friction form factor with no ad-hoc adjustment of model parameters. However, we note significant deviation, beyond experimental errors, in some cases of Fr isotopes.

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“…A study based on Langevin models indicated that employing the chaosweighted friction [64], which predicts a presaddle friction value analogous to that used here, and assuming a small postsaddle friction β, underestimates significantly the measured prescission neutron multiplicity of heavy fissioning systems (A ∼ 250), showing that a larger β [41] needs to be incorporated into model calculations. In addition, multi-dimensional Langevin calculations were made [65,66] which even predict a small decrease of the friction parameter with deformation by introducing a reduction factor k s ( 1) for the wall formula. This type of friction was found to be able to reproduce the fission excitation function, but it also significantly underestimates the measured prescission neutron multiplicity of heavy fissioning systems (A > 240); see Table I in Ref.…”

Section: (B)]mentioning

confidence: 99%

Effect of pre-equilibrium emission on probing postsaddle nuclear dissipation with neutrons

田舰¹,

叶巍²

2016

Chinese Phys. C

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Using the stochastic Langevin model coupled with a statistical decay model, we study the influence of pre-equilibrium (PE) emission on probing postsaddle friction (β) with neutrons. A postsaddle friction value of (14−16.5) ×10 21 s −1 and (11−13) ×10 21 s −1 is obtained from comparing calculated and measured prescission neutron multiplicities of heavy fissioning systems 248 Fm and 256 Fm in the absence and presence of the deformation factor. Moreover, it is found that a larger β is required to fit multiplicity data after the PE effect is accounted for, and that the effect becomes stronger when more energy is removed by PE particles. Our findings suggest that, to more accurately determine the postsaddle friction strength through the measurement of prescission neutrons, in addition to incorporating the contribution of PE evaporation source into the experimental multi-source analysis for particle energy spectra in coincidence with fission fragments, on the theoretical side, it is very important to make a precise evaluation of the energy that PE emission carries away from excited compound systems produced in heavy-ion fusion reactions.

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Incorporation of a tilting coordinate into the multidimensional Langevin dynamics of heavy-ion-induced fission: Analysis of experimental data from fusion-fission reactions

Cited by 59 publications

References 95 publications

Presaddle and postsaddle dissipative effects in fission using complete kinematics measurements

Presaddle and postsaddle dissipative effects in fission using complete kinematics measurements

Investigating the fission dynamics of the following neutron shell closed nuclei within a stochastic dynamical approach: ²¹⁰Po, ²¹²Rn, and ²¹³Fr*

Effect of pre-equilibrium emission on probing postsaddle nuclear dissipation with neutrons

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Incorporation of a tilting coordinate into the multidimensional Langevin dynamics of heavy-ion-induced fission: Analysis of experimental data from fusion-fission reactions

Cited by 59 publications

References 95 publications

Presaddle and postsaddle dissipative effects in fission using complete kinematics measurements

Presaddle and postsaddle dissipative effects in fission using complete kinematics measurements

Investigating the fission dynamics of the following neutron shell closed nuclei within a stochastic dynamical approach: 210Po, 212Rn, and 213Fr*

Effect of pre-equilibrium emission on probing postsaddle nuclear dissipation with neutrons

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Product

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Investigating the fission dynamics of the following neutron shell closed nuclei within a stochastic dynamical approach: ²¹⁰Po, ²¹²Rn, and ²¹³Fr*