Study of thePt189→Ir189→Os189Decay Chain

Permanent magnet electron spectrographs, a double-focusing electron spectrometer, and gamma-scintillation spectrometers have been used to measure the energies and intensities of radiations which accompany the decay of ${\mathrm{Pt}}^{189}$. From these data, the conversion coefficients, multipolarities, and mixing ratios of a number of the transitions have been determined. Some new transitions are reported, and a revised level scheme, incorporating all but one of the observed transitions, is proposed for ${\mathrm{Ir}}^{189}$. A half-life of 10.87±0.12 h has been determined for ${\mathrm{Pt}}^{189}$. The gamma-scintillation spectrum obtained from a pure source of ${\mathrm{Ir}}^{189}$ is reported. The half-life of ${\mathrm{Ir}}^{189}$ which has been measured is 13.3±0.1 days.