Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive $^{222}$Ra and $^{228}$Ra Beams

There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole ($E3$) matrix elements have been determined for transitions in $^{222,228}$Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of $E$3 matrix elements for different nuclear transitions is explained by describing $^{222}$Ra as pear-shaped with stable octupole deformation, while $^{228}$Ra behaves like an octupole vibrator.

The observation of vibrating pear-shapes in radon nuclei (vol 10, 2473, 2019)

Coulomb excitation of the vertical bar T-z vertical bar=1/2, A=23 mirror pair

New isomers in the full seniority scheme of neutron-rich lead isotopes: The role of effective three-body forces

The neutron-rich lead isotopes, up to Pb216, have been studied for the first time, exploiting the fragmentation of a primary uranium beam at the FRS-RISING setup at GSI. The observed isomeric states exhibit electromagnetic transition strengths which deviate from state-of-the-art shell-model calculations. It is shown that their complete description demands the introduction of effective three-body interactions and two-body transition operators in the conventional neutron valence space beyond Pb208. © 2012 American Physical Society.

Total absorption spectroscopy study of the β decay of 86Br and 91Rb

The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyväskylä and further purified using the JYFLTRAP. 86Br and 91Rb are considered to be major contributors to the decay heat in reactors. In addition, 91Rb was used as a normalization point in direct measurements of mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should be renor…