Abstract
The formation and decay of all the gamma-ray emitting states produced in bombarding with protons in the energy range MeV has been studied. Re-examination of the gamma-ray decay scheme of showed no evidence for the existence of either a 1.74- or a 1.84-MeV transition; the value was obtained for the alpha-unstable 5.16-MeV level. Gamma rays from the first excited states of and were also observed; the energy of the latter was determined to be 3.35±0.01 MeV. The formation of the positron-emitting ground state of was studied by means of the annihilation radiation. Giant-resonance structures in the region MeV were observed in the yield curves for all reactions that did not leave the final nucleus in a state. A strong correlation between maximum cross sections and reaction energies is noted, but this correlation in itself does not appear to be sufficient to explain the marked suppression of the final states. It is shown that a resonance in the four-particle system could be responsible for the giant-resonance structures.
- Received 23 December 1965
DOI:https://doi.org/10.1103/PhysRev.145.736
©1966 American Physical Society