Influence of the pairing vibrations on spontaneous fission probability

doi:10.1016/0375-9474(89)90559-9

Nuclear Physics A

Volume 504, Issue 3, 20 November 1989, Pages 589-604

https://doi.org/10.1016/0375-9474(89)90559-9 Get rights and content

Abstract

The potential-energy surface and the mass parameters of the even-even transplutonium elements are evaluated. Our microscopic hamiltonian consists of the Nilsson potential, the two-body residual interaction in the local approximation and the pairing forces. The calculations are performed in the generator coordinate method with the extended gaussian-overlap approximation.

The coupling of the pairing vibrations with the fission mode (elongation and neck) reduces the WKB estimates of the fission lifetimes by a few orders of magnitude.

References (17)

D.M. Brink et al.
Nucl. Phys.
(1968)
A. Góźdź et al.
Nucl. Phys.
(1985)
A. Góźdź et al.
Nucl. Phys.
(1985)
A. Góźdź et al.
Nucl. Phys.
(1986)
D.R. Bès et al.
Nucl. Phys.
(1970)
V.M. Strutinsky
Nucl. Phys.
(1968)
M. Brack et al.
Rev. Mod. Phys.
(1972)
S.G. Nilsson et al.
Nucl. Phys.
(1969)
S. Piłat et al.
Z. Phys.
(1989)

There are more references available in the full text version of this article.

Cited by (63)

Theory of nuclear fission
2022, Progress in Particle and Nuclear Physics
Atomic nuclei are quantum many-body systems of protons and neutrons held together by strong nuclear forces. Under the proper conditions, nuclei can break into two (sometimes three) fragments which will subsequently decay by emitting particles. This phenomenon is called nuclear fission. Since different fission events may produce different fragmentations, the end-products of all fissions that occurred in a small chemical sample of matter comprise hundreds of different isotopes, including $α$ particles, together with a large number of emitted neutrons, photons, electrons and antineutrinos. The extraordinary complexity of this process, which happens at length scales of the order of a femtometer, mostly takes less than a femtosecond but is not entirely over until all the lingering $β$ decays have completed – which can take years – is a fascinating window into the physics of atomic nuclei. While fission may be more naturally known in the context of its technological applications, it also plays a crucial role in the synthesis of heavy elements in astrophysical environments. In both cases, simulations are needed for the many systems or energies inaccessible to experiments in the laboratory. In this context, the level of accuracy and precision required poses formidable challenges to nuclear theory. The goal of this article is to provide a comprehensive overview of the theoretical methods employed in the description of nuclear fission.
Nuclear Data Sheets for A=244
2017, Nuclear Data Sheets
Available information pertaining to the nuclear structure of ground and excited states for all known nuclei with mass numbers A=244 have been compiled and evaluated. The adopted level and decay schemes, as well as the detailed nuclear properties and configuration assignments based on experimental data are presented for these nuclides. When there are insufficient data, expected values from systematics of nuclear properties and/or theoretical calculations are quoted. Unexpected or discrepant experimental results are also noted. Information provided in ²⁴⁴U is tentative as it is from the possible production in the study of 1960Di03 of debris of the first large-scale thermonuclear test (Ivy Mike) of November 1, 1952 in the Pacific Ocean. No new experimental data are available for ²⁴⁴Np with the information for g.s Jπ considered tentative. Experimental work is needed for ²⁴⁴Np as theoretical work and systematics along with the Gallagher-Moszkowski rules that suggest either Jπ=2⁺ or $7^{-}$ . Jπ = ( $7^{-}$ ) g.s has been considered by the evaluator due to population of high spin states in the beta decay study. In ²⁴⁴Pu, a new K isomer was identified and in addition rotational bands built on the isomer have been observed via the deep inelastic excitation. However, there has been no new measurements since the last evaluation to determine the ratio of the energy levels of the first 4⁺ state to the first 2⁺ state (E4+/E2⁺) in ²⁴⁴Pu that showed a discrepancy from a typical value of 3.333. In the current evaluation, the evaluator has considered the 110γ measured in the ²⁴⁴Np β-decay questionable. Further research into the determination of the gammas depopulating these levels is necessary. In ²⁴⁴Am, specifically the (d,p) transfer reaction and in the (n, γ) secondary γ's, there are a large number of gammas that are unplaced. Since its last measurement in 1966, the electron capture dataset has been updated with a tentative partial level scheme for ²⁴⁴Cm which also provided a new half-life measurement for ²⁴⁴Bk. In ²⁴⁴Fm, a fusion evaporation experiment measured the half-life and provided upper limits for the SF, α decay, and ε branching. A summary and compilation of the discovery of various isotopes in this mass region is given in 2013Fr02 (²⁴⁴Np, ²⁴⁴Pu, ²⁴⁴Am, ²⁴⁴Cm, ²⁴⁴Bk, and ²⁴⁴Cf), 2011Me01 (²⁴⁴Es), and 2013Th02 (²⁴⁴Fm). This work supersedes the 2003 evaluation by Y.A. Akovali (2003Ak04).
Spontaneous fission, cluster emission and alpha decay of <sup>222</sup>Ra in a unified description
2017, Annals of Physics
Three disintegration modes of the parent nucleus $^{222} Ra$ , namely the fission, the cluster emission and the alpha decay, are treated in a unified manner. The half-lives are calculated by taking into account the penetration probabilities through the potential barrier along disintegration trajectories in the deformation space appropriate to each kind of decay. These trajectories start from the same parent ground state configuration. The disintegration paths are obtained from the least action principle. The deformation energy is calculated within the macroscopic–microscopic procedure based on the Woods–Saxon two center shell model. The effective mass is determined microscopically with the cranking method and the Gaussian Overlap Approximation. The nuclear shape parametrization is characterized by the most important five degrees of freedom encountered in fission, corresponding to the elongation, the mass asymmetry, the necking and the two fragment deformations. Partial half-life results for alpha-decay and cluster emission processes treated as superasymmetric fission agree with the experimental data. The spontaneous fission half-life is predicted. Molecular states are evidenced for the superasymmetric fission process as a result of the large shell effects in the nascent fragments.
On Microscopic Energy Corrections Around Scission Configuration
2015, Physics Procedia
The spontaneous fission of actinides is analysed by the macroscopic - microscopic method based on the Lublin Strasbourg Drop model and the two deformed Nilsson wells or Yukawa folded single particle potentials. The microscopic corrections are obtained within the Strutinsky prescription and the BCS theory. In the scission point the shell correction possess the additive property but this is not true for pairing correlations during asymmetric fission. Here the shape dependent pairing force of the δ or Gogny type should be used and the pairing strength should grow with increasing deformation of fissioning nucleus. The examples of sponta- neous fission results are presented. The possibility of β decay accompanying the spontaneous fission is noticed.
Multimodal fission from self-consistent calculations
2024, Physical Review C
Coupling shape and pairing vibrations in a collective Hamiltonian based on nuclear energy density functionals (II): Low-energy excitation spectra of triaxial nuclei
2023, arXiv

View all citing articles on Scopus

^☆: Supported in part by the Polish Ministry of National Education, Project CPBP 01.06.

¹: Present address: Department of Physics, Technische Universität München, 8046 Garching, Fed. Rep. Germany.

View full text

Influence of the pairing vibrations on spontaneous fission probability☆

Abstract

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Nucl. Phys.

Rev. Mod. Phys.

Nucl. Phys.

Z. Phys.