Coulomb dissociation of a halo nucleus 11Be at 72 A MeV

Abstract

We have measured the excitation energy spectrum of the 10Be+n system in the Coulomb dissociation of the one-neutron-halo nucleus 11Be on a Pb target at 72 A MeV. We have determined the dipole strength distribution dB ( E1) / dEx which shows a strong peak at about 800 keV excitation energy. The spectral shape is consistent with a direct breakup model. The Coulomb post accelaration effect has been observed also to support the direct breakup mechanism. The E1 dominance of the Coulomb dissociation is confirmed by observed angular distributions of 10Be in the 11Be rest frame.