Nuclear structure of 231Ra

The study of the upper border of the octupole deformation region near A=225, where the octupole deformation vanishes in the presence of a well developed quadrupole field, is of great relevance in order to understand the interplay of octupole and quadrupole collectivities. Within the IS322 collaboration at CERN we carry out a systematic investigation of the heavy Fr-Th nuclei that presently includes 227Fr, 227,228,229Ra, 229Ac and 229,231Th. The heaviest Ra isotope we have studied so far and in which the fast timing βγγ(t) method has been applied is 231Ra.