Ponente
Descripción
The availability, for higher intense beams at Riken, of a 100 pnA $^{238}$U, in combination with the increased efficiency of the $\gamma$-ray detection array compared to the previous EURICA campaign, opens the way to new experimental studies in the largely unexplored region of neutron-rich rare-earth nuclei. The structure of these nuclei is important from both nuclear astrophysics and nuclear structure perspectives, with respect to the r-process formation of the rare-earth-element (REE) abundance peak, nuclear shape changes and shell evolution [1].
With this proposal, we aim at investigating the neutron-rich nuclei with 170$<$A$<$180, focusing on the Er, Dy and Gd isotopes where K-isomers are predicted to appear. The presence of isomers will allow us to perform gamma-ray spectroscopy below the isomeric states for the first time in several nuclei in this region. We will perform isomeric and β-decay measurements, with a focus on 100 ns $\rightarrow$ ms isomers as entry points to the most neutron-rich structures, exploiting the germanium detector array coupled to the WAS3ABi active stopper.
This measurement will provide an insight in quasiparticle structures and energies, shape, sub-shell and K-mixing effects, and help to develop our understanding of the formation of the r-process REE abundance peak.
[1] W.J. Huang et al., Eur. Phys. J. A 55 (2019) 96
