Coulomb dissociation of halo nuclei

Coulomb dissociation of loosely bound nuclei ¹¹Be and ¹⁵C have been studied in a kinematically complete measurement. For ¹¹Be, the n-¹⁰Be relative energy spectrum has been analyzed as a function of the impact parameter, b. The obtained spectrum with b ≥ 30 fm agrees very well with the first order perturbation theory assuming a pure Coulomb process. It suggests that a selection of the impact parameter is effective to exclude the higher order effect and the nuclear breakup contribution from the measured dissociation cross section. The spectroscopic factor for ¹⁰Be(0⁺) ⊗ 1s_1/2 in the ground state is then extracted to be 0.69(3). The result of ¹⁵C has been applied to determine the ¹⁴C(n,γ)¹⁵C cross section, which is relevant to the stellar nuclear synthesis such as the CNO cycle in low mass AGB stars. The obtained neutron capture cross section is consistent with that of the p-wave direct capture process.