The depopulation of ${}_{}{}^{180}{}_{}{}^{}\mathrm{Ta}_{}^{\mathit{m}}{}_{}{}^{}$ by Coulomb excitation was investigated in a thick-target experiment using beams of ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ and ${}_{}{}^{36}{}_{}{}^{}\mathrm{S}$ with energies of 70–130 MeV on disks of natural tantalum. The resulting ${}_{}{}^{180}{}_{}{}^{}\mathrm{Ta}$ ground-state population was measured by detecting its eight-hour decay. At the higher incident energies the observed ${}_{}{}^{180}{}_{}{}^{}\mathrm{Ta}$ yield is dominated by sub-Coulomb neutron pickup transfer reactions on the ${10}^4$ times more abundant ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$. At the lower incident energies in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Ta}$ ground-state yield is found to be compatible with Coulomb excitation of the isomer to an intermediate level with energies ${\mathit{E}}_{\mathit{x}}$<1 MeV and a reduced transition probability B(E2)≃0.02–0.25 Weisskopf units. Consequences for the astrophysical production mechanism of ${}_{}{}^{180}{}_{}{}^{}\mathrm{Ta}$ are discussed.

• Received 11 May 1994

DOI:https://doi.org/10.1103/PhysRevC.50.2198