Study of the Beyond-Neutron-Threshold Structure in the $N=50$ Region from $\beta$-Delayed Neutron and $\gamma$ Spectroscopy at ALTO
Résumé
We have recently launched an experimental program at ALTO to investigate the structure of the neutron-threshold region. This endeavor was further encouraged by the unexpected observation of “ultra”-high-energy γ-rays (8-9 MeV) in the β-delayed emission products of 83Ga (Z=31; N=52; T1/2=312 ms; Qβ=11.7 MeV) sources collected at the BEDO station. These results clearly point towards the existence of structures in the threshold region of the daughter-nucleus excitation spectrum, governing the decay properties in the 78Ni region.