Inelastic Scattering of Alpha Particles by Be9 at 28.5 MeV

Differential cross sections of the elastic scattering and the inelastic scatterings of alpha particles from Be 9 at the incident energy of 28.5 MeV are obtained. The angular distributions for the ground state and 2.43 MeV state show the clear diffractive nature. For the positive parity state, the phase relation of the experiment does not agree with the diffraction theory, and the interaction radius is smaller than those for the ground state and the collective state. The peak at 1.7 MeV in pulse height spectrum is considered to be caused by a final state interaction between the S wave neutron and the Be 8 nucleus.