Depopulation of ${}^{180}{Ta}^{m}$ by Coulomb excitation and possible astrophysical consequences

The depopulation of

{}^{180}{Ta}^{m}

by Coulomb excitation was investigated in a thick-target experiment using beams of

{}^{32}S

and

{}^{36}S

with energies of 70–130 MeV on disks of natural tantalum. The resulting

{}^{180}{Ta}

ground-state population was measured by detecting its eight-hour decay. At the higher incident energies the observed

{}^{180}{Ta}

yield is dominated by sub-Coulomb neutron pickup transfer reactions on the

10^{4}

times more abundant

{}^{181}{Ta}

. At the lower incident energies in

{}^{180}{Ta}

ground-state yield is found to be compatible with Coulomb excitation of the isomer to an intermediate level with energies

E_{x}

<1 MeV and a reduced transition probability B(E2)≃0.02–0.25 Weisskopf units. Consequences for the astrophysical production mechanism of

{}^{180}{Ta}

are discussed.

This publication has 27 references indexed in Scilit:

Depopulation ofTam180by Coulomb excitation and possible astrophysical consequences