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.
Primary author
Mr
Guillaume Maquart
(IPNl)
