Neutrons arising from the breakup of a 30 MeV/nucleon C-19 beam on a tantalum target have been measured using the 98 element array DEMON. A narrow, forward peaked neutron angular distribution, with a corresponding momentum spread considerably smaller than those measured simultaneously for N-21, O-22 and F-24 was observed for charged fragments with Z < Z(proj). Interpreted in terms of the core-breakup reaction model, the results support the existence of a one neutron halo in C-19.
Marques, F., Ninane, A., & et al. (1996). Neutrons from the breakup of C-19. Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics, 381(4), 407-412. https://doi.org/10.1016/0370-2693(96)00617-X (Original work published 1996)