Abstract
The reaction has been studied using an anticoincidence-shielded scintillation spectrometer. Excitation functions were measured for proton energies of 0.85-1.96 MeV. Resonances were found at bombarding energies of 1.061±0.002, 1.55, 1.739±0.002, and 1800±0.004 MeV, corresponding to the well-known excited states of at 8.283±0.003, 8.75, 8.915±0.003, and 8.972±0.005 MeV. Gamma-ray spectra show that the 8.28-MeV level decays to the ground state (54%), the 5.24-MeV level (43%), and the 6.18-MeV level (2%). In addition, coincidence spectra revealed a 1% branch through the 6.86-MeV level, which level decays to the 5.24-MeV level. No evidence was found for decay of the 8.28-MeV level to a previously reported level at 7.17 MeV. The 8.75-MeV level decays by way of the 5.19-MeV level and by way of the 6.18-MeV level. The 8.915-MeV level decays to the ground state (21%), the 5.19-MeV level (23%), the 6.18-MeV level (30%), and the 6.86-MeV level (26%). The 8.97-MeV level decays 93% to the ground state and 6% to the 5.19-MeV state. Based upon measured transition strengths and the angular distribution of the ground-state gamma rays, the spin of the 8.915-MeV level is established as ; the 8.972-MeV level is or and the 6.86-MeV level has a spin of either or . Off-resonance spectra for near 1.2 MeV indicate direct capture into the 6.79-MeV level, the ground state, and also the 7.55-MeV level. The excitation function of radiation to ground from the bound states of indicate that the broad level of at 9.53 MeV decays almost entirely directly to the ground state or to the ground state and to unbound levels.
- Received 19 April 1966
DOI:https://doi.org/10.1103/PhysRev.149.863
©1966 American Physical Society