Fission dynamics within time-dependent Hartree-Fock. II. Boost-induced fission

Goddard, P.; Stevenson, P. D.; Rios, Arnau

doi:10.1103/physrevc.93.014620

Cited by 57 publications

(40 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[29] using TDHFB, the treatment of dynamical pairing has solved the threshold anomaly [15,28,30,31], i.e. the fact that in a range of deformation larger than the barrier position, heavy systems were not fissioning in TDDFT when pairing was neglected.…”

mentioning

confidence: 99%

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

2017

View full text Add to dashboard Cite

We show that the total kinetic energy (TKE) of nuclei after the spontaneous fission of 258 Fm can be well reproduced using simple assumptions on the quantum collective phase-space explored by the nucleus after passing the fission barrier. Assuming energy conservation and phase-space exploration according to the stochastic mean-field approach, a set of initial densities is generated. Each density is then evolved in time using the nuclear time-dependent density-functional theory with pairing. This approach goes beyond mean-field by allowing spontaneous symmetry breaking as well as a wider dynamical phase-space exploration leading to larger fluctuations in collective space. The total kinetic energy and mass distributions are calculated. New information on the fission process: fluctuations in scission time, strong correlation between TKE and collective deformation as well as pre-scission particle emission, are obtained. We conclude that fluctuations of TKE and mass are triggered by quantum fluctuations.PACS numbers: 21.60. Jz, 24.75.+i, 25.85.Ca, 27.90.+b The dynamical modeling of a nuclear Fermi quantum droplet that spontaneously breaks into two pieces represents one of the most exciting challenges of nuclear physics today. Beside its description, a deeper microscopic understanding of spontaneous fission (SF) is of great importance to form the heaviest elements at the frontier of the nuclear chart [1][2][3] or to further improve our knowledge about the competition between the r-process and fission during the primordial nucleosynthesis [4]. Motivated also by its importance in nuclear energy production, intensive experimental efforts have been made to accumulate precise measurements [5][6][7][8][9]. In recent years, an increasing effort was made to remove empirical ingredients that are employed in macroscopic modeling of fission and use microscopic theories [10,11]. The nuclear Density Functional Theory (DFT) is a suitable starting point to describe some aspects related to the large amplitude collective motion (LACM). A minimal information obtained from DFT is the adiabatic collective energy landscape [11]. One challenge to describe spontaneous fission (SF) is the necessity to explicitly treat the evolution as a quantum dynamic in collective space. Progresses have been made with the Time-Dependent Generator Coordinate Method (TDGCM) [12][13][14]. This theory by treating quantally collective degrees of freedom (DOF) is promising. However, the adiabatic assumption often made becomes critical especially close to scission [15]. Dissipation of the collective motion into internal excitations also plays a key role to understand the excitation energy and kinetic energy sharing during fragments separation [16]. Understanding this dissipation requires to include many-body states beyond the adiabatic limit [17]. It is yet unclear how the pre-scission neutron and proton emissions can be incorporated in the TDGCM.The nuclear time-dependent DFT (TDDFT) overcomes some of these limitations. With recently developed symmetry unrest...

show abstract

mentioning

confidence: 99%

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

2017

View full text Add to dashboard Cite

show abstract

“…A number of models was developed for a description of the reaction mechanism in the multi-nucleon transfer process in quasi-fission reactions [1][2][3][4]. Within the last few years the time-dependent Hartree-Fock (TDHF) approach [5][6][7] has been utilized for studying the dynamics of quasifission [7][8][9][10][11][12][13][14][15][16][17] and scission dynamics [18][19][20][21][22][23]. Such calculations are now numerically feasible to perform on a 3D Cartesian grid without any symmetry restrictions and with much more accurate numerical methods [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Multinucleon transfer in central collisions of U238+U238

et al. 2017

View full text Add to dashboard Cite

Quantal diffusion mechanism of nucleon exchange is studied in the central collisions of 238 U + 238 U in the framework of the stochastic mean-field (SMF) approach. For bombarding energies considered in this work, the di-nuclear structure is maintained during the collision. Hence, it is possible to describe nucleon exchange as a diffusion process for mass and charge asymmetry. Quantal neutron and proton diffusion coefficients, including memory effects, are extracted from the SMF approach and the primary fragment distributions are calculated.

show abstract

“…Pairing correlations are also critical in order to have an efficient mechanism to maintain the sphericity of the Fermi surface while the shape of the mother nucleus evolves from a compact form up to scission. In the absence of an efficient mechanism, which would redistribute the nucleon pairs at the level-crossings occurring at the Fermi level, see Figure 1, a nucleus would fail to fission, unless excited to very large energies or elongated well beyond the our fission barrier [9,24,25].…”

Section: Pos(inpc2016)225mentioning

confidence: 99%

Microscopic Description Of Nuclear Fission

Bulgac¹,

Jin²,

Magierski³

et al. 2017

Proceedings of the 26th International Nuclear Physics Conference — PoS(INPC2016)

View full text Add to dashboard Cite

We describe the fission dynamics of 240 Pu within an implementation of the Density Functional Theory (DFT) extended to superfluid systems and real-time dynamics. We demonstrate the critical role played by the pairing correlations, which even though are not the driving force in this complex dynamics, are providing the essential lubricant, without which the nuclear shape evolution would come to a screeching halt. The evolution is found to be much slower than previously expected in this fully non-adiabatic treatment of nuclear dynamics, where there are no symmetry restrictions and all collective degrees of freedom (CDOF) are allowed to participate in the dynamics.

show abstract

Fission dynamics within time-dependent Hartree-Fock. II. Boost-induced fission

Cited by 57 publications

References 42 publications

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

Microscopic Phase-Space Exploration Modeling ofFm258Spontaneous Fission

Multinucleon transfer in central collisions of U238+U238

Microscopic Description Of Nuclear Fission

Contact Info

Product

Resources

About