Effects of microscopic transport coefficients on fission observables calculated by the Langevin equation

Usang, M. D.; Ivanyuk, F. A.; Ishizuka, Chikako; Chiba, Satoshi

doi:10.1103/physrevc.94.044602

Cited by 59 publications

(50 citation statements)

References 43 publications

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“…One can see that the use of the finite-depth TCWS potential (blue) reproduces the experimental peak positions and their widths better than the infinite-depth TCSM potential (green). For comparison, results of the 3D Langevin model using the TCSM [5] is shown (black). Both of the 3D TCSM model and the 4D TCWS model can reproduce well the whole structure of the experimental FFMDs.…”

Section: Numerical Resultsmentioning

confidence: 99%

“…The fifth parameter ǫ is defined as the ratio of the potential height E at z = 0 to the value E 0 of the left and right harmonic oscillator potentials at z = 0, see Fig 1. In our present and previous calculations [5], we have fixed ǫ = 0.35. This value leads to shapes that are very close to the so called optimal shapes [16] -the shapes that correspond to the lowest liquid drop energy at fixed elongation and mass asymmetry.…”

Section: The Two-center Shell Modelmentioning

confidence: 99%

“…In this model, however, important features of nuclear dynamics such as energy dissipation cannot be treated, due to the assumption of overdamped motion. Thus several important quantities in fission such as the prescission kinetic energy (PKE) [5] and the fission time scale [6] have not been considered at the moment in this framework.…”

Section: Introductionmentioning

confidence: 99%

“…The model can also determine the fission time scale, which is not the case for the Random-walk method [3]. At present there are several groups which use the Langevin approach for the description of the fission process [5,[7][8][9][10][11]. Due to the difficulty of the calculation of the multi-dimensional transport coefficients used in the Langevin equations, and due to the lack of sufficient resources for numerical calculations the number of shape parameters in most cases is restricted to 2 or 3 collective variables.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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We developed a four-dimensional Langevin model which can treat the deformation of each fragment independently and applied it to low energy fission of 236 U, the compound system of the reaction n+ 235 U. The potential energy is calculated with the deformed two-center Woods-Saxon (TCWS) and the Nilsson type potential with the microscopic energy corrections following the Strutinsky method and BCS pairing. The transport coefficients are calculated by macroscopic prescriptions. It turned out that the deformation for the light and heavy fragments behaves differently, showing a sawtooth structure similar to that of the neutron multiplicities of the individual fragments ν(A). Furthermore, the measured total kinetic energy T KE(A) and its standard deviation are reproduced fairly well by the 4D Langevin model based on the TCWS potential in addition to the fission fragment mass distributions. The developed model allows a multi-parametric correlation analysis among, e.g., the three key fission observables, mass, TKE, and neutron multiplicity, which should be essential to elucidate several long-standing open problems in fission such as the sharing of the excitation energy between the fragments.

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Section: Numerical Resultsmentioning

confidence: 99%

Section: The Two-center Shell Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2017

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“…3.1 where the calculation is done for a range of excitation energy. Previously [9], we have shown for 236 U detailed analysis of the fission observables calculated using Langevin equation with microscopic transport coefficients.…”

Section: Introductionmentioning

confidence: 99%

Effects of microscopic transport coefficients on fission observables calculated by Langevin equation and its systematics

et al. 2017

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Abstract. The Langevin dynamical description of fission observables is inspired by the random evolution of shape parameters across the potential surface. In these work, we shall use mass and friction tensors inspired from Linear Response Theory (microscopic transport coefficients) and obtain the fission observables associated with these calculations. We compare these microscopic results with calculations using hydrodynamical mass tensor and wall-window friction tensor (macroscopic transport coefficients). We are able to calculate the fission product yield, Coulomb kinetic energy and prescission kinetic energy from the Langevin calculation. This allows us to observe the systematic of average light and heavy mass fission product yield calculated using both microscopic and macroscopic calculations. We also compare the results of microscopic and macroscopic calculation total kinetic energy (TKE) with Viola's TKE systematics. In the case of 236,239 U compound nucleus, we do the microscopic calculation for several excitation energy up to 30 MeV and afterwards compare it to the TKE of experimental data and corresponding macroscopic TKE. Reasonable agreement of microscopic TKE to experiment is obtained which shows decreasing TKE with increasing excitation energy. Macroscopic TKE however, is independent of excitation energy and thus contrary to experimental data.

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