Determination of the Po-190 alpha reduced width

The isotope Po-190 was produced in the Sm-144(Ti-48,2n) reaction and its alpha-decay energy and half-life were measured to be 7.49(4) MeV and 2.0(-1.0)(+0.5) ms, respectively. These data compare as follows with preliminary values reported by Quint et al.: E(alpha) = 7482(20) keV and a T-1/2 = 9.6(-4.4)(+47) ms. While the two energies agree, the half-lives differ by a factor of almost 5. The earlier data yield an ct reduced width which is much smaller than those of neighboring nuclides; our Po-190 energy and half-life result in a width that fits the overall alpha-decay-rate systematics in the mass region above the Z = 82 closed shell.