First beta-decay spectroscopy of In-135 and new beta-decay branches of In-134

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.

Fine structure in the α decay of 218At

An α-decay study of 218At was performed at the CERN-ISOLDE facility. Laser-ionized beams of 218At were mass separated and implanted into an α−γ detection setup. Coincidence α−γ data were collected for the first time and a more precise half-life value of T1/2=1.27(6) s was measured. A new α-decay scheme was deduced based on the extracted reduced α-decay widths for fine-structure decays. The results from this work lead to a preferred spin and parity assignment of Jπ=(3−); however, Jπ=(2)− cannot be fully excluded.

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

Fine structure in the alpha decay of At-218

New beta-decaying state in Bi-214

13 pags., 7 figs., 3 tabs.