Alpha-Alpha Scattering in the Energy Range 5 to 9 Mev

The scattering of alpha particles from helium has been experimentally studied in the energy range 5 to 9 Mev by the measurement of three excitation functions at the center-of-mass angles 30^∘{} 33{'}, 54^∘{} 44{'}, and 70^∘{} 7{'}. A phase-shift analysis has been performed which indicates that only the S- and D-wave phase shifts are necessary to fit the data in this energy region. Only the well-known D state at approximately 2.9 Mev in Be⁸ was observed. The D state has been compared to the single-level dispersion theory and level parameters have been extracted which are compatible with the alpha-particle model of Be⁸.