Fragmentation of unstable neutron-rich oxygen beams

Fragmentation of secondary beams of neutron-rich, unstable ${}^{19,20,21}\mathrm{O}$ isotopes at beam energies near 600 MeV/nucleon was studied by measuring the production cross sections for carbon, nitrogen, and oxygen fragments. Data for stable ${}^{17,18}\mathrm{O}$ beams were obtained as well. The measurements serve to illuminate the isospin dependence of the fragmentation process. The experimental results are compared to those from empirical parametrization and those from abrasion-ablation models.