Decay ofPm144

Abstract

${\mathrm{Pm}}^{144}$ has been produced by an ($\alpha , n$) reaction on ${\mathrm{Pr}}^{141}$ in the Copenhagen cyclotron. The half-life of ${\mathrm{Pm}}^{144}$ has been determined and found to be closer to 450 days rather than to the previously reported value of 300 days. The decay of the nuclide to levels in ${\mathrm{Nd}}^{144}$ has been studied, using a 100-channel gamma-ray analyzer and a six-gap $\beta$-ray spectrometer. Three $\gamma$ rays have been found, with the following energies: 474, 615, and 695 kev, respectively. It has been determined that the three $\gamma$ rays are $E2\mathrm{}$ transitions and that they are in cascade with one another. A decay scheme for ${\mathrm{Pm}}^{144}$, consistent with the experimental data, has been proposed.