Chemically separated and isotopically separated sources of 6.2-day ${}_{}{}^{206}{}_{}{}^{}\mathrm{Bi}$ produced by the ($p,xn$) reactions on lead were used to study the excited states of ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$. $\gamma$-ray data were taken with a Compton-suppression spectrometer and with a Ge(Li)-Ge(Li) two-parameter analyzer system. From these, 66 $\gamma$ rays were identified in the decay of ${}_{}{}^{206}{}_{}{}^{}\mathrm{Bi}$ and 61 of these transitions have been placed from coincidence results, energy sums and differences, and intensity considerations in a decay scheme with 19 excited states. New levels at 2826.4, 2939.6, 3225.5, and 3244.1 keV have been deduced. Spins and parities for all but one excited state were deduced from published internal-conversion electron intensities, relative $\gamma$-ray intensities, $log\mathrm{ft}$ values, and existing angular distribution measurements from particle reactions. The branching ratios, transition multipolarities, and lifetimes for many of the ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ levels were calculated by using the wave functions that result from shell-model calculations with phenomenological as well as realistic interactions, and calculations using the two-nucleon random phase approximation.

• Received 21 April 1972

DOI:https://doi.org/10.1103/PhysRevC.6.1870