Bulletin of the American Physical Society
5th Joint Meeting of the APS Division of Nuclear Physics and the Physical Society of Japan
Volume 63, Number 12
Tuesday–Saturday, October 23–27, 2018; Waikoloa, Hawaii
Session 1WCA: Nuclear Fission Turns 80 I |
Hide Abstracts |
Chair: Ramona Vogt, Lawrence Livermore National Laboratory Room: Hilton Kohala 2 |
Tuesday, October 23, 2018 9:00AM - 9:30AM |
1WCA.00001: A closer look at prompt fission data Invited Speaker: Patrick Talou In this talk, I will provide a brief overview of recent advances in the modeling of the decay of fission fragments and the description of post-scission prompt data through the use of the FREYA and CGMF Monte Carlo fission event generators, which have been developed to describe the complex distributions and correlations of prompt neutrons and photons. Of fundamental interest are questions related to the dynamics of the fission process, the sharing of the excitation energy between the two fragments at scission, the production of angular momentum in each partner fragment, and the nuclear structure of neutron-rich nuclei formed in the fission process. Of particular interest to applications are correlations in energy, multiplicity and angle of the emitted particles, which can be used advantageously as signatures of the fission process. |
Tuesday, October 23, 2018 9:30AM - 10:00AM |
1WCA.00002: Overview of recent theory advances in fission yields Invited Speaker: Jorgen Randrup The theory of fission dynamics is currently experiencing a multitude of significant advances. The present talk gives an overview of the most recent ones, with a view towards the calculation of fission fragment yields. Among the microscopic approaches, the time-dependent density functional approach with pairing has now become sufficiently tractable to allow extensive dynamical calculations to be carried out and a variety of important quantities have been extracted, including the resulting fragment mass distributions as well as the excitations and kinetic energies of the fragments. Spontaneous fission has also been addressed in various ways. Moreover, it has become possible to use microscopic calculations to test some of the key assumptions made in the transport treatments; in particular, it was found that the dissipation is indeed very strong, lending support to the idealization of overdamped shape evolution. Important advances have been made in the transport treatment of nuclear shape dynamics by invoking more microscopic information. In particular, the use of microscopically calculated shape-dependent level densities to guide the stochastic evolution has established a consistent framework for treating the dependence on energy and angular-momentum because the gradual disappearance of shell and pairing effects are automatically included. Notably, the large pairing correlations in the fission barrier region may cause the resulting fragment yields to exhibit a non-monotonic energy dependence. Furthermore, use of the microscopic level densities of the individual nascent fragments as a basis for distributing the available excitation energy at scission leads to a reasonably good reproduction of the fragment mass dependence of the neutron multiplicity. |
Tuesday, October 23, 2018 10:00AM - 10:30AM |
1WCA.00003: Fission yield measurement using multi-nucleon transfer reactions Invited Speaker: Kentaro Hirose The multi-nucleon transfer (MNT) reaction, where a few nucleons are given from a beam nucleus to a target nucleus, is very useful way to populate a multitude of nuclides in a wide excitation energy range. We have developed a detector system at the JAEA tandem accelerator facility to measure fission observables such as fission-fragment mass distributions (FFMD), prompt fission neutron multiplicities and so on for compound nuclei produced in the MNT reaction using actinide targets. The system consists of a silicon DE-E telescope and multi-wire proportional counters for detection of ejectiles and fission fragments, respectively. An array of liquid scintillators is placed around the target for neutron detection. By identifying the ejectile, the initial compound nucleus is also identified. At high excitation energies, fission of nuclides produced via neutron emission from the initial compound nucleus also contribute to FFMD. In the present study, effects of the multi-chance fission on FFMDs were successfully separated by a combination of a systematic data set obtained from experiments using 18O beams and actinide targets and a dynamical fission calculation based on the fluctuation-dissipation model. In the workshop, results of the prompt-fission neutron measurement will also be presented. |
Tuesday, October 23, 2018 10:30AM - 11:00AM |
1WCA.00004: COFFEE BREAK
|
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700