Abstract
-particle scattering by has been studied in the energy range 18.9 to 30 MeV, using the Minnesota MP tandem Van de Graaff accelerator. The target consisted of 40 μg/ of oxygen in the form of LiOH on a 20-μg/ carbon backing. Absolute cross sections were determined with an oxygen gas target. Excitation functions were measured in 20-keV steps at eight angles over the entire energy range, using computer control of the accelerator's analyzing magnet. The center-of-mass angles were selected to be zeros of the Legendre polynomials to for elastic scattering. Inelastic scattering to the 6.05-6.13-MeV doublet in was also studied. Elastic differential cross sections were measured at 20 energies between 18.9 and 23.0 MeV. Nonstatistical structure is observed in the excitation functions. The spins and parities of the resonances are tentatively assigned on the basis of the elastic excitation functions. A phase-shift analysis of the differential cross sections has unambiguously identified resonances at 20.70 MeV ( KeV) and 21.10 MeV ( keV) in . They may be the members of the lowest-two negative-parity rotational bands in , which are expected to be near 20 MeV.
- Received 20 November 1970
DOI:https://doi.org/10.1103/PhysRevC.3.1729
©1971 American Physical Society