The measurements presented here provide evidence for the existence of di-cluster structures in 10–12,14Be. Certainly, if the breakup process samples the overlap between the wavefunctions of the ground state and the excited states, the first-chance cluster breakup cross-sections, shown in Fig. 4(a), indicate that the xHe+A−xHe cluster structure does not decrease over the mass range A=10, 12 and 14. Given also that the decay energy threshold increases with mass number, the present data may even indicate a slight increase in clustering. The breakup cross-sections also appear to demonstrate that these nuclei possess a stronger structural overlap with an α–Xn–α configuration, although the reaction mechanics by which this final state is reached may be complex. That is to say that the dominant structural mode of the neutron rich isotopes may be identified with two alpha-particles plus valence neutrons. These comprehensive measurements of the neutron-removal and cluster breakup for the first time provide experimental data whereby the structure of the most neutron-rich Be isotopes can be modeled via their reactions.
