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 ${\mathrm{Be}}^8$ 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 ${\mathrm{Be}}^8$.

• Received 13 August 1959

DOI:https://doi.org/10.1103/PhysRev.117.525