23-27 January 2017
Bormio, Italy
Europe/Berlin timezone

Backbending in the pear shaped 223Th nucleus : First evidence of a high spin octupole to quadrupole shape transition in the actinides.

23 Jan 2017, 17:27
3m
Bormio, Italy

Bormio, Italy

Speaker

Mr Guillaume Maquart (IPNl)

Description

An experiment as been realized using the EUROBALL IV array at Strasbourg to study the fission products produced in the reaction 208Pb(180; F ). Nevertheless, the experiment also lead to the production of 223Th produced in the fusion-evaporation channel of this reaction with three neutrons evaporated. The structure of thorium isotopes is known to present features of octupole collectivity. The aim of the present talk is to report new results about the structure of 223Th, with possible consequences on the characterization of its octupole properties. Indeed, the quality of the data allowed us to establish more than 25 new levels and extend the yrast band up to 49/2+ . This observation has brought to light a sharp backbending occuring at the highest spins promoting the 223Th as the heavier thorium isotope having an accident observed in its moment of inertia. The interpretation of this phenomenon in terms of band crossing will be discussed by comparing experimental evidences with various calculations. This backbending is the first expected evidence of a quadrupole-octupole shape transition in the actinides at high spin. Moreover, a new non-yrast structure was discovered showing very dierent features and further details will be presented.

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