Fast-timing spectroscopy with the <i>ν</i>-ball2 spectrometer

The fast-timing method has been used in a high-statistics experiment at ALTO@IJCLab to perform lifetime measurements of excited states in exotic nuclei. These observables and their corresponding transition probabilities are key fingerprints for the structure of atomic nuclei, as they are sensitive to small components of the wave function. Neutron-rich nuclei have been populated in a two-step fission-induced experiment. In the first stage, the neutron beam was produced by the LICORNE source in an inverse kinematics reaction with a pulsed 7 Li beam delivered by the Tandem accelerator, incident on an H 2 gas cell. The resulting neutron beam with an average energy of about 2 MeV was used in a second step to induce fissions on the 238 U secondary target. The hybrid high-efficiency v-ball2 array comprising 24 clover detectors and 20 UK FATIMA LaBr 3 (Ce) scintillators was used to detect the emitted gamma rays. Improvements are discussed in comparison to the previous v-ball1 campaign and preliminary results of the current experiment are presented.