Fast-timing measurements using LaBr₃(Ce) detectors in the neutron-rich N = 20 region

Variations in the proton and neutron numbers inside the nucleus lead to changes in the nuclear shell structure. Nuclear transition rates are sensitive indicators of those changes, so-called “nuclear shell evolution”, which depend in part on knowledge of the level lifetimes. Radioactive nuclei were implanted into a CeBr₃ scintillator coupled to a Position-Sensitive Photomultiplier Tube (PSPMT) as part of a β decay experiment in the neutron-rich N = 20 region conducted at the National Superconducting Cyclotron Laboratory (NSCL). This allowed for correlating the decays to the implanted ions using spatial and temporal techniques. 15 LaBr₃(Ce) detectors, providing fast timing measurement and γ radiation detection, were used to generate time-difference spectra for β-delayed γ radiation following a decay event to measure half-lives. In the neutron-rich N = 20 region, corrections for the energy-dependent time-walk effects and validation results will be provided.