Particle-Core Couplings Close To Neutron-Rich Doubly-Magic Nuclei

Preliminary results are presented from a recent campaign of experiments, performed at the PF1B cold-neutron facility at ILL (Grenoble, France), in which gamma-ray spectroscopy of neutron-rich nuclei produced in neutron induced fission on U-235 and Pu-241 targets was performed. By using the EXILL array, consisting of EXOGAM, GASP and ILL-Clover detectors, and a digital triggerless data acquisition system, gamma coincidences over several microseconds time windows were studied. This allowed to obtain new information on nuclei around Sn-132, such as Te-132, Sb-133 and Sn-130, in which microsecond isomeric states occur. Preliminary results on Bi-210, populated by cold-neutron capture, are also shown. The data offer the possibility to investigate the couplings between core excitations and valence particles, around the doubly magic nuclei Sn-132 and Pb-208.