Hafnium-184 was identified as a product of the irradiations of natural tungsten and enriched ${}_{}{}^{186}{}_{}{}^{}\mathrm{W}$ with 92- and 200-MeV protons. The activity was produced by the ${}_{}{}^{186}{}_{}{}^{}\mathrm{W}\mathrm{}(p,3p)\mathrm{}{}_{}{}^{184}{}_{}{}^{}\mathrm{Hf}$ reaction. Mass-separated samples of ${}_{}{}^{184}{}_{}{}^{}\mathrm{Hf}$ were used to study its $\beta$ and $\gamma$ decay. Some $\gamma -\gamma$ and $\beta -\gamma$ coincidence measurements were performed. The following characteristics were observed: half-life, 4.12± 0.05 h; $\beta$-ray end-point energies, 1100± 30, 850± 50, and 740± 30 keV; and $\gamma$-ray energies, 41.4, 43.9, 47.9, 139.1, 181.0, and 344.9 keV. A decay scheme is proposed for ${}_{}{}^{184}{}_{}{}^{}\mathrm{Hf}$ based on the experimental data and theoretical predictions for the excited level structure of ${}_{}{}^{184}{}_{}{}^{}\mathrm{Ta}$.

• Received 29 November 1972

DOI:https://doi.org/10.1103/PhysRevC.8.340