Photodisintegration of 9Be through the 1 /2+ state and cluster dipole resonance

Photodisintegration of ⁹Be through the 1 /2⁺ state near neutron threshold and cluster dipole resonance below giant dipole resonance was measured with quasi-monochromatic γ -ray beams produced in the inverse Compton scattering of laser photons. The cross section for the 1 /2⁺ state is revisited, being consistent with the 2001 data. The cross section for the cluster dipole resonance is consistent with the cluster dipole sum-rule which however degenerates for the two-body (n -⁸Be ) and three-body (n -α -α ) configurations.