Probing nuclear dissipation with particle multiplicity in heavy-ion-induced light fissioning systems

Ye, W.; Wang, N.; Tian, J.

doi:10.1103/physrevc.90.041604

Cited by 11 publications

(9 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Refined dynamical approaches along these lines have continued with increasing degree of sophistication and success (e.g. [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]).…”

Section: Introductionmentioning

confidence: 99%

Microscopic dynamical description of proton-induced fission with the constrained molecular dynamics model

et al. 2015

View full text Add to dashboard Cite

The microscopic description of nuclear fission still remains a topic of intense basic research. Understanding nuclear fission, apart from a theoretical point of view, is of practical importance for energy production and the transmutation of nuclear waste. In nuclear astrophysics, fission sets the upper limit to the nucleosynthesis of heavy elements via the r-process. In this work we initiated a systematic study of intermediate energy proton-induced fission using the Constrained Molecular Dynamics (CoMD) code. The CoMD code implements an effective interaction with a nuclear matter compressibility of K=200 (soft EOS) with several forms of the density dependence of the nucleon-nucleon symmetry potential. Moreover, a constraint is imposed in the phase-space occupation for each nucleon restoring the Pauli principle at each time step of the collision. A proper choice of the surface parameter of the effective interaction has been made to describe fission. In this work, we present results of fission calculations for proton-induced reactions on : a) 232 Th at 27 and 63 MeV, b) 235 U at 10, 30, 60 and 100 MeV, and c) 238 U at 100 and 660 MeV. The calculated observables include fission-fragment mass distributions, total fission energies, neutron multiplicities and fission times. These observables are compared to available experimental data. We show that the microscopic CoMD code is able to describe the complicated many-body dynamics of the fission process at intermediate and high energy and give a reasonable estimate of the fission time scale. Sensitivity of the results to the density dependence of the nucleon symmetry potential (and, thus, the nuclear symmetry energy) is found. Further improvements of the code are necessary to achieve a satisfactory description of low energy fission in which shell effects play a dominant role.Understanding the mechanism of nuclear fission, that is the transformation of a single heavy nucleus into two receeding fragments, has been a long journey of fruitful research and debate and, still today, is far from being complete. Upon its discovery, fission was interpreted by Meitner and Frisch [22] as the division of a charged liquid drop due to the interplay of the repulsive Coulomb force between the protons and the surface tension due to the attractive nucleon-nucleon interaction. In the seminal paper of Bohr and Wheeler [23], fission was described with a liquid-drop model and the first estimates of fission probalilities were obtained based on statistical arguments. The first detailed calculations of potential energies of deformed nuclear drops were performed by Frankel and Metropolis in 1947 [24] employing the ENIAC, one of the first digital computers. Despite the success in the interpretation of fission based on the liquid-drop model, the prevailing asymmetry in the mass distribution of the minor actinides could not be deciphered until shell corrections to the macroscopic liquid drop were taken into account (see below). A detailed statistical model that could describe asymmetric fission was...

show abstract

Section: Introductionmentioning

confidence: 99%

Microscopic dynamical description of proton-induced fission with the constrained molecular dynamics model

et al. 2015

View full text Add to dashboard Cite

show abstract

“…In such a sharp Z partitioning scheme, charge fluctuations are nonexistent: the isobaric charge variance oz , which corresponds to the width of the fission-fragment Z distribution at fixed A (often referred to as charge-dispersion [22]), is zero. To our knowledge, the absence of charge fluctuations is common to all available Langevin codes used at day, although the most probable charge may be derived from one or another hypotheses [2][3][4][23][24][25][26][27][28][29].…”

mentioning

confidence: 99%

Description of isotopic fission-fragment distributions within the Langevin approach

2015

View full text Add to dashboard Cite

International audienceDynamical calculations based on the four-dimensional stochastic Langevin approach are extended to thedescription of fragment isotopic distributions in fission at moderate-to-high excitation energy. Benefiting fromprevious theoretical work on charge-asymmetry relaxation times, and existing experimental charge-dispersioncurves from low-energy fission, charge fluctuations are introduced at the scission point in an effective way.Comparison with recent suited measurements shows a good description over the full fragment production. Thedevelopment proposed in this work can easily be implemented in other codes used in the field

show abstract

“…In refs. [21,22], the results of twodimensional Langevin calculations of the mass distribution were presented for the 227 Pa compound nucleus at low excitation energies. Moreover, the shell corrections were taken into account when calculating the potential energy, level-density parameter, and the deformation dependence of the penetrability coefficient in determining the particle-emission widths.…”

Section: Mass Distribution Of Fission Fragmentsmentioning

confidence: 99%

“…In such a "sharp" scheme, charge fluctuations are inexistent: the isobaric charge variance σ Z -given by the width of the charge-dispersion curve at fixed mass [221]-is zero. To our knowledge, the absence of charge fluctuations is common to (nearly) all available Langevin codes, although the most probable charge may be derived from one or another hypotheses [21,27,52,63,185,[225][226][227][228].…”

Section: Charge Variancementioning

confidence: 99%

Fission fragment distributions within dynamical approach

et al. 2017

View full text Add to dashboard Cite

The review covers recent developments and achievements in the dynamical description of fission process at high excitation energy. It is shown that the dynamical approach based on multidimensional Langevin equations combined with the statistical description of nuclear decay by particles evaporation is capable of fairly well describing the formation of fission fragment mass-energy, charge, and angular distributions of fission fragments in coincidence with the pre-and post-scission particle emission. The final yields of fission and evaporation residues channels products could be obtained. The detailed description of fission dynamics allows studying different stages of fission process, indicating the most important ingredients governing fission process and studying in detail such fundamental nuclear properties as nuclear viscosity and fission timescale. The tasks and perspectives of multidimensional dynamical approach are also discussed.

show abstract

Probing nuclear dissipation with particle multiplicity in heavy-ion-induced light fissioning systems

Cited by 11 publications

References 55 publications

Microscopic dynamical description of proton-induced fission with the constrained molecular dynamics model

Microscopic dynamical description of proton-induced fission with the constrained molecular dynamics model

Description of isotopic fission-fragment distributions within the Langevin approach

Fission fragment distributions within dynamical approach

Contact Info

Product

Resources

About