The $\alpha$-decay properties of ${}^{190}$Po were investigated through the use of a fragment mass analyzer in conjunction with a double-sided Si strip detector. The isotope was produced via the ${}^{96}\mathrm{Mo}{(}^{96}\mathrm{Mo},2n)$ reaction, and its $\alpha$-decay energy and $T_{1/2}$ were measured as 7529(10) keV and ${2.4}_{-0.3}^{+0.4\mathrm{}}$ ms, respectively. The resulting reduced width is nearly identical to that of the ${}^{192,194}\mathrm{Po}$ isotopes. This is believed to result from significant mixing between the ground state $\pi \mathrm{}\left(2p\right)\mathrm{}$ and the low-lying $0^{+}\pi \mathrm{}(4p-2h)\mathrm{}$ intruder state in the Po parent. The result provides further evidence for shape coexistence in the light Po isotopes. In addition, ${}^{191}\mathrm{Po}$ was unambiguously identified, and the ${}^{186}\mathrm{Pb}$ $\alpha$-decay branch was determined experimentally for the first time.

• Received 3 February 1997

DOI:https://doi.org/10.1103/PhysRevC.55.R2142