Abstract
Ge(Li) spectrometry has been used to study the -ray deexcitation of states of produced in the reaction at MeV. Precision excitation energies were determined from both singles and coincidence measurements. Multiparameter data collection techniques were used to store -ray spectra measured at in coincidence with groups populating various final states of . particles were detected in an annular detector at , thus defining a narrow cone of forward-going recoils which stopped in the Ni target backings. The observed Doppler shifts were analyzed, via the Doppler-shift attenuation method, to determine the lifetimes of the initial -emitting states. Resulting excitation energies (in keV) and meanlives (in psec) for the first 15 excited states of are as follows: 1982.16 ± 0.20 (), 3555.07 ± 0.45 (> 4.0), 3634.50 ± 0.40 (1.33 ± 0.20), 3920.6 ± 0.4 (0.024 ± 0.010), 4456.1 ± 0.5 (0.065 ± 0.015), 5098.5 ± 1.2 (0.062 ± 0.025), 5260.4 ± 1.2 (0.12 ± 0.03), 5336.4 ± 0.6 (0.20 ± 0.04), 5377.8 ± 1.2 (< 0.03), 5530.5 ± 0.6 (< 0.025), 6196.3 ± 1.2 (...), 6351.3 ± 0.6 (< 0.035), 6404.4 ± 1.2 (0.03 ± 0.015), 6881.6 ± 1.2 (< 0.025), and 7116.9 ± 1.2 (<0.025). The angular correlations data for each transition were fitted, as a function of , in order to determine relative intensities and thus branching ratios. An analysis of the correlation data provides confirmation or support for previously reported conclusions on spin-parity assignments, and in addition restricts possible assignments for the 6351-keV state to . These results are compared to previous data on and to theoretical considerations.
- Received 30 January 1973
DOI:https://doi.org/10.1103/PhysRevC.7.2239
©1973 American Physical Society