Abstract
The gamma rays from the capture in of protons of energy between 0.27 and 1.2 Mev have been studied using large scintillation crystals. Excitation functions of the gamma rays leading to the 0-, 0.72-, 1.74-, 2.15-, 3.58-, and 5.16-Mev states of were computed from the measured gamma-ray spectra. In addition to the resonances previously known to exist at 0.33-, 0.99-, and 1.086-Mev proton energy [corresponding to () 6.88-, () 7.48-, and () 7.56-Mev states in ], evidence was found only for the -wave resonance near 1 Mev [() 7.5-Mev state in ] postulated by Mozer and by Dearnaly and for the influence of higher lying states. This work leaves unexplained the large isotopic-spin impurity of the 6.88-Mev level. Appreciable nonresonant capture was found for the transitions to the 0-, 0.72-, 3.58-, and 5.16-Mev states, which is probably not -wave for the latter two transitions. Accurate energy measurements and coincidence work showed that the 5.16-Mev level of is populated in preference to the 5.11-Mev level, contradicting earlier work of Clegg. Also, experimental evidence has been found which appears to be in contradiction to the spin assignment for the 7.56-Mev level of and raises doubts about the spin assignment of the 5.16-Mev level.
- Received 13 April 1959
DOI:https://doi.org/10.1103/PhysRev.115.1227
©1959 American Physical Society