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Related papers: Quantification of spin alignment in fission by sim…

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We investigate the angular momentum removal from fission fragments (FFs) through neutron and $\gamma$-ray emission, where we find that about half the neutrons are emitted with angular momenta $\ge 1.5\hbar$ and that the change in angular…

Nuclear Theory · Physics 2021-12-01 I. Stetcu , A. E. Lovell , P. Talou , T. Kawano , S. Marin , S. A. Pozzi , A. Bulgac

This study proposes a theoretical model for studying the spin characteristics and angular correlations of fission fragments of heavy nuclei. The mechanisms of spin formation, including the influence of transverse vibrations, are considered…

Nuclear Theory · Physics 2025-03-13 D. E. Lyubashevsky , A. A. Pisklyukov , S. V. Klyuchnikov , P. V. Kostryukov

The strong deformation present immediately after scission has consequences for the angular momentum population of the fragments as well as the angular distribution of their decay radiation. We find that the usual spin-cutoff…

Nuclear Theory · Physics 2019-03-13 G. F. Bertsch , T. Kawano , LM. Robledo

This paper presents a theoretical description of the spin distributions of fragments from low-energy induced and spontaneous nuclear fission, expressed in an analytical form. The mechanism of pumping high spin values for deformed fission…

We extend a conventional description of the fusion-fission fragment angular distributions by introducing the correlation between compound nucleus states carrying different total angular momenta. This correlation results in the strong…

Nuclear Theory · Physics 2019-11-28 Oleksandr Gorbachenko , Sergey Kun

Angular distribution and correlation measurements are an essential part in nuclear structure experiments, especially when spectroscopic information of a specific nucleus is unknown. In most cases, the experimental determination of the…

Nuclear Theory · Physics 2022-03-09 A. Chalil , T. Materna , O. Litaize , A. Chebboubi , F. Gunsing

Background: The role of angular momentum in fission has long been discussed but the observable effects are difficult to quantify. Purpose: We discuss a variety of effects associated with angular momentum in fission and present quantitative…

Nuclear Theory · Physics 2021-01-27 R. Vogt , J. Randrup

The emission of neutrons and gamma rays by fission fragments reveal important information about the properties of fragments immediately following scission. The initial fragment properties, correlations between fragments, and emission…

This study explores the role of nucleon exchange for the generation of the fission fragment angular momenta. For a number of typical fission cases, samples of 10,000 shape evolutions are generated by Langevin simulation and, subsequently,…

Nuclear Theory · Physics 2026-03-31 Jorgen Randrup , Pavel Nadtochy , Christelle Schmitt , Katarzyna Mazurek

Fission fragment angular distributions can provide an important constraint on fission theory, improving predictive fission codes, and are a prerequisite for a precise ratio cross section measurement. Available anisotropy data is sparse,…

In recent years, investigations of angular distributions of fragments in neutron-induced nuclear fission have been extended to intermediate energies, up to 200 MeV, as well as to a wide range of target isotopes. Using as an example the…

Nuclear Theory · Physics 2022-01-12 A. L. Barabanov , A. S. Vorobyev , A. M. Gagarski , O. A. Shcherbakov , L. A. Vaishnene

During nuclear fission, a heavy nucleus splits into two rotating fragments. The associated angular momentum is large, yet the mechanism of its generation and its dependence on the mass of fragments remain poorly understood. In this Letter,…

Nuclear Theory · Physics 2021-08-11 Petar Marević , Nicolas Schunck , Jorgen Randrup , Ramona Vogt

Nuclear time-dependent density functional theory is used to investigate spin generation and entanglement of fission fragments in spontaneous fission of $^{252}$Cf, incorporating both axial and non-axial deformations. Axially symmetric…

Nuclear Theory · Physics 2026-05-26 B. Li , D. D. Zhang , D. Vretenar , T. Nikšić , P. W. Zhao , J. Meng

New experimental and theoretical results obtained in 2021 made it acutely clear that more than 80 years after the discovery of nuclear fission we do not understand the generation and dynamics of fission fragment (FF) intrinsic spins well,…

Nuclear Theory · Physics 2023-12-29 Guillaume Scamps , Ibrahim Abdurrahman , Matthew Kafker , Aurel Bulgac , Ionel Stetcu

We differentiate the event-by-event n-$\gamma$ multiplicity data from \ce{^{252}Cf}(sf) with respect to the energies of the emitted particles as well as their relative angles of emission. We determine that neutron emission enhances…

The anisotropy in the angular distribution of the fusion-fission and quasifission fragments for the $^{16}$O+$^{238}$U, $^{19}$F+$^{208}$Pb and $^{32}$S+$^{208}$Pb reactions is studied by analyzing the angular momentum distributions of the…

We present the first fully unrestricted microscopic calculations of the primary fission fragment intrinsic spins and of the fission fragments' relative orbital angular momentum for $^{236}$U$^*$, $^{240}$Pu$^*$, and $^{252}$Cf using the…

Nuclear Theory · Physics 2022-01-14 Aurel Bulgac , Ibrahim Abdurrahman , Kyle Godbey , Ionel Stetcu

A recent analysis of experimental data [J. Wilson $et. al$, Nature $\mathbf 590$, 566 (2021)] found that the angular momenta of nuclear fission fragments are uncorrelated. Based on this finding, the authors concluded that the spins are…

Nuclear Theory · Physics 2021-08-11 J. Randrup , R. Vogt

Several sources of angular anisotropy for fission fragments and prompt neutrons have been studied in neutron-induced fission reactions. These include kinematic recoils of the target from the incident neutron beam and the fragments from the…

Nuclear Theory · Physics 2020-09-02 A. E. Lovell , P. Talou , I. Stetcu , K. J. Kelly
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