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 (Edecay≲100 keV) in lighter (Z⩽10) nuclei, and the possibility of extending it to heavier, more neutron-rich nuclei will be discussed.