Production of nuclei in neutron unbound states via primary fragmentation of ⁴⁸Ca

The method of sequential neutron decay spectroscopy beginning with a primary beam of 60 MeV/nucleon ⁴⁸Ca was investigated as a potential tool to measure unbound resonances in neutron-rich nuclei. Neutrons were measured in coincidence with fragments, and unbound resonances were observed for ¹⁰Li, ^12,13Be, and ²³O. The method is currently limited to resonances with small decay energies (E_decay ≲ 100   keV) in lighter (Z ≤ 10) nuclei, and the possibility of extending it to heavier, more neutron-rich nuclei will be discussed.