The tantalum isotopes ${\mathrm{Ta}}^{170}$ and ${\mathrm{Ta}}^{171}$ were produced via the following reactions: ${\mathrm{Ho}}^{165}({\mathrm{C}}^{12},6n){\mathrm{Ta}}^{171}$, ${\mathrm{Tb}}^{159}({\mathrm{O}}^{16},4n){\mathrm{Ta}}^{171}$, ${\mathrm{Ho}}^{165}({\mathrm{C}}^{12},7n){\mathrm{Ta}}^{170}$, and ${\mathrm{Tb}}^{159}({\mathrm{O}}^{16},5n){\mathrm{Ta}}^{170}$. The half-life of ${\mathrm{Ta}}^{171}$ was determined to be 25 ± 2 min and of ${\mathrm{Ta}}^{170}$, 7 ± 2 min. About 60 $\gamma$ rays were assigned to the ${\mathrm{Ta}}^{171}$ decay, while in ${\mathrm{Ta}}^{170}$ decay, only the excitations of the first- and second-excited states of ${\mathrm{Hf}}^{170}$ were observed.

• Received 16 October 1970

DOI:https://doi.org/10.1103/PhysRevLett.25.1499