Temperature dependence of nuclear fission time in heavy-ion fusion-fission reactions
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Authors
Eccles, CS
Roy, S
Gray, Thomas
Zaccone, Alessio
Journal Title
Physical Review C - Nuclear Physics
Publisher
American Physical Society
Volume
96
Number
054611
Type
Article
This Version
AM
Metadata
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Eccles, C., Roy, S., Gray, T., & Zaccone, A. Temperature dependence of nuclear fission time in heavy-ion fusion-fission reactions. Physical Review C - Nuclear Physics, 96 (054611) https://doi.org/10.1103/PhysRevC.96.054611
Abstract
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' theory, which improves on the Bohr-Wheeler estimate by including the time-scale related to many-particle dissipative processes along the deformation coordinate. However, Kramers' formula breaks down for sufficiently high excitation energies where Kramers' assumption of a large barrier no longer holds. In the regime $T>1$ MeV, Kramers' theory should be replaced by a new theory based on the Ornstein-Uhlenbeck first-passage time method that is proposed here. The theory is applied to fission time data from fusion-fission experiments on $^{16}$O+$^{208}$Pb $\rightarrow$ $^{224}$Th. The proposed model provides an internally consistent one-parameter fitting of fission data with a constant nuclear friction as the fitting parameter, whereas Kramers' fitting requires a value of friction which falls out of the allowed range. The theory provides also an analytical formula that in future work can be easily implemented in numerical codes such as CASCADE or JOANNE4.
Identifiers
External DOI: https://doi.org/10.1103/PhysRevC.96.054611
This record's URL: https://www.repository.cam.ac.uk/handle/1810/271723
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