Pm145: A New Alpha Activity

${\mathrm{Pm}}^{145}$ was prepared by means of the chain ${\mathrm{Sm}}^{144}(n, \gamma ){\mathrm{Sm}}^{145}\{\mathrm{E}.\mathrm{C}.\mathrm{}\}\{\to \}{\mathrm{Pm}}^{145}$. The alpha activity of ${\mathrm{Pm}}^{145}$ was studied by means of a gridded ionization chamber and a 512-channel pulse-height analyzer. The alpha energy was found to be 2.24±0.04 MeV, and the branching (2.8±0.6)×${10}^{-9\mathrm{}}$ alphas per disintegration. With a view to proving that the alpha activity was not due to ${\mathrm{Sm}}^{147}$, a further Sm-Pm separation was carried out with no detectable change in the branching ratio. The thermal neutron capture cross sections of ${\mathrm{Sm}}^{144}$ and ${\mathrm{Sm}}^{145}$ were estimated to be 0.7 and 110 b.