Abstract
The mean lifetimes of seven nuclear levels of have been measured by the Doppler-shift attenuation method. The reaction was used to populate the levels. rays were observed at 0° to the beam with a Ge(Li) detector. The results, when averaged with previous work, yield the following mean lives (in psec) for the indicated levels: 0.891 (12.25±1.75), 1.528 (3.5±0.6), 1.984 (1.74±0.34), 2.211 (), 2.572 (5.7±0.9), 2.969 (0.060±0.013), and 3.059 (0.040±0.01), where the levels are designated by their excitation energies (in MeV). For the five lowest levels the lifetimes were obtained from an analysis of Doppler-shifted line shapes; the remaining two lifetimes were determined from conventional centroid-shift analysis. The latter method also gave a lifetime of 5.2±0.9 psec for the 1.346-MeV level of . Some information was obtained on the mixing ratios of the ground-state and first-excited-state transitions from the MeV level of . Evidence for a odd-parity rotational band in is discussed.
- Received 10 May 1968
DOI:https://doi.org/10.1103/PhysRev.173.1063
©1968 American Physical Society