Neck Rupture and Scission Neutrons in Nuclear Fission

Abstract

Just before a nucleus fissions a neck is formed between the emerging fission fragments. It is widely accepted that this neck undergoes a rather violent rupture, despite no direct experimental evidence, and only a few contentious theoretical treatments of this fission stage were ever performed in the more than eight decades since nuclear fission was experimentally observed by Hahn and Strassmann and described by Meitner and Frisch in 1939. In the same year, Bohr and Wheeler conjectured that the fission of the nuclear liquid drop would likely be accompanied by the rapid formation of tiny droplets, later identified with either scission neutrons or other ternary fission fragments, a process which has not yet been discussed in a fully quantum many-body framework. The main difficulty in addressing both of these stages of nuclear fission is both are highly non-equilibrium processes. Here we will present the first fully microscopic characterization of the scission mechanism, along with the spectrum and the spatial distribution of scission neutrons, and some upper limit estimates for the emission of charged particles.

5 pages, 4 figures

References in corpus (13)

• Theory of ultracold Fermi gases
• Brownian shape motion on five-dimensional potential-energy surfaces: Nuclear fission-fragment mass distributions
• Dynamical synthesis of 4He in the scission phase of nuclear fission
• Fission fragments intrinsic spins and their correlations
• Event-by-event study of prompt neutrons from 239Pu(n,f)
• Fission fragment distributions and their impact on the r-process nucleosynthesis in neutron star mergers
• Formation and distribution of fragments in the spontaneous fission of 240Pu
• Measures of complexity and entanglement in fermionic many-body systems
• Extension of the Hauser-Feshbach Fission Fragment Decay Model to Multi-Chance Fission
• Entanglement entropy, single-particle occupation probabilities, and short-range correlations
• Emission of Scission Neutrons in the Sudden Approximation
• Pure quantum extension of the semiclassical Boltzmann-Uehling-Uhlenbeck equation
• Examining the justification for the introduction of a fermion localization function

Cited by in corpus (9)

• Nuclear Quantum Many-Body Dynamics: From Collective Vibrations to Heavy-Ion Collisions (2nd edition)
• Non-Markovian character and irreversibility of real-time quantum many-body dynamics
• Time-Dependent Density Functional Theory Description of ${}^{238}$U(n,f), ${}^{240,242}$Pu(n,f) and ${}^{237}$Np(n,f) Reactions
• Non-Equilibrium Aspects of Fission Dynamics within the Time Dependent Density Functional Theory
• Local Quantum Cooling for Large Fermi Systems with Pairing
• Calculation of tetraneutron-induced reaction cross sections with optical and Hauser-Feshbach statistical models
• Isotopic fission yields of ${}^{240}$Pu as a function of the excitation energy
• A critical assessment of the current implementations of the Generator Coordinate Method
• Quasi-elastic scattering for the nuclear ground state structure: An intriguing case of ${}^{30}$Si