Speaker
Description
The multi-humped fission barrier is the result of superposing microscopic shell corrections to the macroscopic liquid drop model [1]. A manifestation of that is the existence of shape isomers [2, 3], as observed in several actinide nuclides. However, the - most often - double-humped barrier is much more than just a concept, since it is related to several fission observables. These data may have an impact on both fundamental nuclear physics and nuclear applications. Sometimes, model calculations of the barrier are performed and observables like various cross sections are predicted [4], which then have to withstand comparison with experimental results. In a recent work [5] it was demonstrated how different measured data from the decay of the shape isomer in $^{235}$U together with fission fragment properties could be used to estimate barrier parameters and to construct the shape of the fission barrier. While that work is based on neutron-induced fission measurements, a recent experiment at GSI was performed to study fission isomers, produced in fragmentation reactions, with the FRS. Data analysis from this experiment is still ongoing, but we will give an overview of the results obtained so far and present the current status of the data treatment.
References:
[1] V. M. Strutinsky, Nucl. Phys. $\textbf{A95}$, 420 (1967).
[2] S. Bjørnholm and J. E. Lynn, Rev. Mod. Phys. $\textbf{52}$, 725 (1980).
[3] P. Thirolf and D. Habs, Prog. Part. Nucl. Phys. $\textbf{49}$, 325 (2002).
[4] M. Sin, R. Capote, M.W. Herman, and A.Trkov, Nucl. Data Sheets $\textbf{139}$, 138 (2017).
[5] A. Oberstedt and S. Oberstedt, Phys. Rev. C $\textbf{104}$, 024611 (2021).