Decay ofTc97Ground State

The half-life of the ground state of ${\mathrm{Tc}}^{97}$ was found to be (2.6±0.4)×${10}^6$ years by comparison of its $K$ x-ray intensity with that from the 90-day ${\mathrm{Tc}}^{97m}$ isomeric state. The $\frac{L}{K}$-capture ratio of ${\mathrm{Tc}}^{97}$ was compared with that of ${\mathrm{Tc}}^{96}$; a somewhat larger ratio is indicated for the former. No $\gamma$ rays were observed that could be attributed to ${\mathrm{Tc}}^{97}$. The relation of these results to the occurrence of technetium in certain stars and to its possible occurrence in the earth's crust is discussed. Improved measurements of the ${\mathrm{Tc}}^{98}$ $\gamma$-ray energies yielded values of 669±5 kev and 769±6 kev.