Excitation curves for the ${\mathrm{Be}}^9(p, d){\mathrm{Be}}^8$ (ground state) reaction have been measured at observation angles of 15°, 45°, 70°, 90°, 110°, and 135° for proton energies between 0.8 and 3.0 Mev. These curves show pronounced resonance structure and strong interference effects between different levels. About 60 angular distributions and the total cross-section curve were constructed from the 6 differential cross-section curves. The angular distributions are peaked forward, except in the region near 1.6 Mev, where a broad resonance, interfering with nonresonant amplitudes, causes the angular distribution to become almost symmetric about 90°. The occurrence of forward peaking at all energies and the good agreement of the angular distribution at 2.84 Mev with a theoretical stripping curve suggest that a pickup process can account for a sizeable fraction of the reaction cross section, even at energies as low as 1 Mev. The total cross section indicates a resonance at 0.93 and weak maxima at 1.25, 1.65, and 2.3 Mev, but not at the $T=1\mathrm{}$ level at 2.56 Mev. The differential cross section for the ${\mathrm{Be}}^9(p, \alpha ){\mathrm{Li}}^6$ (ground state) reaction was measured at 90° from 0.8 to 3.0 Mev. In addition to the 0.93-Mev peak, this curve shows a pronounced minimum near 1.4 Mev and a weak anomaly at 2.56±0.02 Mev indicating a slight violation of the isotopic spin selection rule. An upper limit of 4×${10}^{-3\mathrm{}}$ is obtained for the $T=0\mathrm{}$ impurity of the $2^{+}$, $T=1\mathrm{}$ state at 8.89 Mev in ${\mathrm{B}}^{10}$.

• Received 27 August 1956

DOI:https://doi.org/10.1103/PhysRev.104.1307