Speaker
Description
In this work, we present recent results obtained in different neutron-induced fission campaigns at Lohengrin (ILL), using a hybrid setup made of HPGe clover detectors and LaBr3 scintillators. The latter were employed to measure lifetimes, down to a few ps, using γ-ray fast-timing techniques [1]. In particular, results on $^{131}$Sb [2] and $^{96}$Rb [3] will be discussed. In the first case, the lifetime of the 11/2$^+$ state was measured, yielding T$_{1/2}$ = 3(2) ps, the first such result in neutron-rich antimony nuclei and one of the shortest ever measured in beam with this experimental technique. Consequences on the origin and development of collectivity in the vicinity of the doubly magic $^{132}$Sn nucleus will be presented in the framework of the shell model. In the second case, particular emphasis will be given to the observation of a retarded E2 transition deexciting the 4− state in 96Rb. This γ ray connects the strongly deformed band above 450 keV with near-spherical low-lying states. Its impact on the shape-coexistence phenomenon in this exotic mass region around N=60 will be addressed.
[1] J.-M. Régis et al., Nucl. Instrum. Methods Phys. Res., Sect. A 955, 163258 (2020).
[2] S. Bottoni et al., Phys. Rev. C 107, 014322 (2023).
[3] E. R. Gamba, S. Bottoni et al., Phys. Rev. C 108, 064301 (2023).