Excitation of the 180mTa isomer in (γ,n) reactions and its astrophysical relevance

The yield has been determined for the excitation of 180gTa (Jπ=1+) from the 181Ta(γ,n) reaction by measurements of γ rays emitted following the electron capture and β-decays of the 8.15 h ground state. The probability σm/(σm+σg) for the production of the 180mTa isomer (Jπ=9−) after γ absorption in the energy region from 8 to 13 MeV was deduced. The role of the initial and final spins on the reaction yield, along with the relevance for nucleosynthesis of 180mTa, is discussed.