Fragment Yields Calculated in a Time-Dependent Microscopic Theory of Fission

Younes, W.; Gogny, D.

doi:10.2172/1053671

Cited by 20 publications

(52 citation statements)

References 16 publications

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“…The SkM* EDF favors slightly more asymmetric configurations whereas we observe the opposite for D1S. Note that the shift of the D1S peak toward symmetry is consistent with earlier work by Younes and Gogny relying on a different collective space and a totally different numerical implementation both of the DFT and TDGCM+GOA solver [34]; see also [33] for details of the TDGCM+GOA solver used then. The widths of the predicted mass yields match the experiment within roughly 1 mass unit.…”

Section: Fission Yields Obtained With Skm* and D1ssupporting

confidence: 89%

“…To build a low deformation wave packet, we begin with computing a series of quasi-bound states as described in [33,34]. This is achieved by extrapolating the inner potential barrier with a quadratic form, which defines a new potential V (q).…”

Section: Initial Statementioning

confidence: 99%

“…In this work, we adopted the empirical approach described in [34,52], which is based on computing the flux of the collective wave packet. The TDGCM+GOA equation implies the following continuity equation for the quantity |g(q, t)| 2 γ 1/2 (q),…”

Section: Fission Fragment Distributionsmentioning

confidence: 99%

“…While the TDGCM was already introduced as early as 1991 [25], there have been very few applications to the calculation of fission fragment distributions [33,34]. Here, we will perform a comprehensive study by examining in details the role in the collective dynamics of the initial state and of the collective inertia.…”

Section: Introductionmentioning

confidence: 99%

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Fission fragment charge and mass distributions inPu239(n,f)in the adiabatic nuclear energy density functional theory

Regnier

Dubray

Schunck³

et al. 2016

Phys. Rev. C

141

120

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Background: Accurate knowledge of fission fragment yields is an essential ingredient of numerous applications ranging from the formation of elements in the r-process to fuel cycle optimization for nuclear energy. The need for a predictive theory applicable where no data is available, together with the variety of potential applications, is an incentive to develop a fully microscopic approach to fission dynamics.Purpose: In this work, we calculate the pre-neutron emission charge and mass distributions of the fission fragments formed in the neutron-induced fission of 239 Pu using a microscopic method based on nuclear density functional theory (DFT).Methods: Our theoretical framework is the nuclear energy density functional (EDF) method, where large amplitude collective motion is treated adiabatically using the time dependent generator coordinate method (TDGCM) under the Gaussian overlap approximation (GOA). In practice, the TDGCM is implemented in two steps. First, a series of constrained EDF calculations map the configuration and potential energy landscape of the fissioning system for a small set of collective variables (in this work, the axial quadrupole and octupole moments of the nucleus). Then, nuclear dynamics is modeled by propagating a collective wave packet on the potential energy surface. Fission fragment distributions are extracted from the flux of the collective wave packet through the scission line.Results: We find that the main characteristics of the fission charge and mass distributions can be well reproduced by existing energy functionals even in two-dimensional collective spaces. Theory and experiment agree typically within 2 mass units for the position of the asymmetric peak. As expected, calculations are sensitive to the structure of the initial state and the prescription for the collective inertia. We emphasize that results are also sensitive to the continuity of the collective landscape near scission.Conclusions: Our analysis confirms that the adiabatic approximation provides an effective scheme to compute fission fragment yields. It also suggests that, at least in the framework of nuclear DFT, three-dimensional collective spaces may be a prerequisite to reach 10% accuracy in predicting pre-neutron emission fission fragment yields.

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Section: Fission Yields Obtained With Skm* and D1ssupporting

confidence: 89%

Section: Initial Statementioning

confidence: 99%

Section: Fission Fragment Distributionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fission fragment charge and mass distributions inPu239(n,f)in the adiabatic nuclear energy density functional theory

Regnier

Dubray

Schunck³

et al. 2016

Phys. Rev. C

141

120

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show abstract

“…two to three orders of magnitude slower than typical single-particle excitations. Such a separation is the central assumption of the time-dependent generator coordinate method (TDGCM), which provides an effective, quantum-mechanical method to compute fission fragment yields [25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Description of induced nuclear fission with Skyrme energy functionals: Static potential energy surfaces and fission fragment properties

et al. 2014

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Eighty years after its experimental discovery, a description of induced nuclear fission based solely on the interactions between neutrons and protons and quantum many-body methods still poses formidable challenges. The goal of this paper is to contribute to the development of a predictive microscopic framework for the accurate calculation of static properties of fission fragments for hot fission and thermal or slow neutrons. To this end, we focus on the 239 Pu(n,f) reaction and employ nuclear density functional theory with Skyrme energy densities. Potential energy surfaces are computed at the Hartree-Fock-Bogoliubov approximation with up to five collective variables. We find that the triaxial degree of freedom plays an important role, both near the fission barrier and at scission. The impact of the parameterization of the Skyrme energy density and the role of pairing correlations on deformation properties from the ground-state up to scission are also quantified. We introduce a general template for the quantitative description of fission fragment properties. It is based on the careful analysis of scission configurations, using both advanced topological methods and recently proposed quantum many-body techniques. We conclude that an accurate prediction of fission fragment properties at low incident neutron energies, although technologically demanding, should be within the reach of current nuclear density functional theory.

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Microscopic Calculation of Fission Fragment Mass Distributions at Increasing Excitation Energies

Schunck¹,

Matheson²,

Regnier³

2020

Compound-Nuclear Reactions

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Fragment Yields Calculated in a Time-Dependent Microscopic Theory of Fission

Cited by 20 publications

References 16 publications

Fission fragment charge and mass distributions inPu239(n,f)in the adiabatic nuclear energy density functional theory

Fission fragment charge and mass distributions inPu239(n,f)in the adiabatic nuclear energy density functional theory

Description of induced nuclear fission with Skyrme energy functionals: Static potential energy surfaces and fission fragment properties

Microscopic Calculation of Fission Fragment Mass Distributions at Increasing Excitation Energies

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