English
Related papers

Related papers: Scaling laws, transient times and shell effects in…

200 papers

Fission excitation functions of compound nuclei in a mass region where shell effects are expected to be very strong are shown to scale exactly according to the transition state prediction once these shell effects are accounted for. The fact…

Nuclear Experiment · Physics 2008-11-26 Th. Rubehn , K. X. Jing , L. G. Moretto , L. Phair , K. Tso , G. J. Wozniak

Fission in 3He and 4He induced reactions at excitation energies between the fission barrier and 140 MeV has been investigated. Twentythree fission excitation functions of various compound nuclei in different mass regions are shown to scale…

Nuclear Experiment · Physics 2007-05-23 Th. Rubehn , K. X. Jing , L. G. Moretto , L. Phair , K. Tso , G. J. Wozniak

Emission lines from highly-excited states (n >= 5) of H- and He-like ions have been detected in astrophysical sources and fusion plasmas. For such excited states, R-matrix or distorted wave calculations for electron-impact excitation are…

Instrumentation and Methods for Astrophysics · Physics 2016-08-17 L. Fernandez-Menchero , G. Del Zanna , N. R. Badnell

Essential properties of halo nuclei can be described in terms of a few low-energy constants. For neutron halo nuclei, analytical results can be found for wave functions and electromagnetic transition matrix-elements in simple but…

Nuclear Theory · Physics 2008-12-18 S. Typel , G. Baur

A systematic study of fission-barrier dependence on excitation energy has been performed using the self-consistent finite-temperature Hartree-Fock+BCS (FT-HF+BCS) formalism with the SkM* Skyrme energy density functional. The calculations…

Nuclear Theory · Physics 2009-08-18 J. A. Sheikh , W. Nazarewicz , J. C. Pei

We examine the manifestation of transient effects in fission by analysing experimental data where fission is induced by peripheral heavy-ion collisions at relativistic energies. Available total nuclear fission cross sections of 238U at 1 A…

Nuclear Experiment · Physics 2009-11-10 B. Jurado , C. Schmitt , K. -H. Schmidt , J. Benlliure , A. R. Junghans

We propose a configuration-interaction (CI) representation to calculate induced nuclear fission with explicit inclusion of nucleon-nucleon interactions in the Hamiltonian. The framework is designed for easy modeling of schematic…

Nuclear Theory · Physics 2021-02-16 G. F. Bertsch , K. Hagino

Quantum shell effects are known to affect the formation of fragments in nuclear fission. Shell effects also affect quasi-fission reactions occurring in heavy-ion collisions. Systematic time-dependent Hartree-Fock simulations of 50Ca+176Yb…

Nuclear Theory · Physics 2021-10-19 C. Simenel , P. McGlynn , A. S. Umar , K. Godbey

Rate coefficients for collisional processes such as rotational and vibrational excitation are essential inputs in many astrophysical models. When rate coefficients are unknown, they are often estimated using known values from other systems.…

Astrophysics of Galaxies · Physics 2015-06-22 Kyle M. Walker , B. H. Yang , P. C. Stancil , N. Balakrishnan , R. C. Forrey

A new experimental approach is introduced to investigate the relaxation of the nuclear deformation degrees of freedom. Highly excited fissioning systems with compact shapes and low angular momenta are produced in peripheral relativistic…

Nuclear Experiment · Physics 2009-11-10 B. Jurado , C. Schmitt , K. -H. Schmidt , J. Benlliure , T. Enqvist , A. R. Junghans , A. Kelic , F. Rejmund

Peripheral collisions with radioactive heavy-ion beams at relativistic energies are discussed as an innovative approach for probing the transient regime experienced by fissile systems evolving towards quasi-equilibrium. A dedicated…

Nuclear Experiment · Physics 2014-11-20 C. Schmitt , K. -H. Schmidt , A. Kelić , A. Heinz , B. Jurado , P. N. Nadtochy

Accounting for viscous damping within Fokker-Planck equations led to various improvements in the understanding and analysis of nuclear fission of heavy nuclei. Analytical expressions for the fission time are typically provided by Kramers'…

Nuclear Theory · Physics 2017-12-06 Chris Eccles , Sanil Roy , Thomas H. Gray , Alessio Zaccone

We present a statistical-model description of fission, in the framework of compound-nucleus decay, which is found to simultaneously reproduce data from both heavy-ion-induced fusion reactions and proton-induced spallation reactions at…

Nuclear Theory · Physics 2010-10-27 Davide Mancusi , Robert J. Charity , Joseph Cugnon

Fission excitation functions have been measured for a chain of neighboring compound nuclei, from 207Po to 212Po. We present a new analysis which provides a determination of the fission barriers and ground state shell effects with nearly…

Nuclear Experiment · Physics 2007-05-23 L. Phair , L. G. Moretto , K. X. Jing , L. Beaulieu , D. Breus , J. B. Elliott , T. S. Fan , Th. Rubehn , G. J. Wozniak

Coulomb fission mechanism may take place if the maximum Coulomb-excitation energy transfer in a reaction exceeds the fission barrier of either the projectile or target. This condition is satisfied by all the reactions used for the earlier…

Helium-like ions provide the most important X-ray spectral diagnostics in high temperature fusion and astrophysical plasmas. We previously presented computed collision strengths for O~VII including relativistic fine structure, levels up to…

Astrophysics · Physics 2009-11-11 Franck Delahaye , Anil K. Pradhan , Claude J. Zeippen

Cross-section and neutron-emission data from heavy-ion fusion-fission reactions are consistent with the fission of fully equilibrated systems with fission lifetime estimates obtained via a Kramers-modified statistical model which takes into…

Nuclear Theory · Physics 2009-12-31 J. P. Lestone , S. G. McCalla

We consider the dependence of collective flow on the nuclear surface thickness in a Boltzmann--Uehling--Uhlenbeck transport model of heavy ion collisions. Well defined surfaces are introduced by giving test particles a Gaussian density…

Nuclear Theory · Physics 2008-11-26 D. Klakow , G. Welke , W. Bauer

We use Faddeev's decomposition to solve the shell-model problem for three nucleons. The dependence on harmonic-oscillator excitations allowed in the model space, up to $32 \hbar\Omega$ in the present calculations, and on the…

Nuclear Theory · Physics 2008-11-26 P. Navratil , B. R. Barrett

The linear response approach to nuclear transport has been extended to pair correlations. The latter are treated within a mean field approximation to a pairing interaction with constant matrix elements $G$. The constraint of particle number…

Nuclear Theory · Physics 2009-10-31 F. A. Ivanyuk , H. Hofmann
‹ Prev 1 2 3 10 Next ›