Low-Lying Excited States ofSc46Populated in the Thermal-Neutron Capture ReactionSc45(n,γ)Sc46

The thermal-neutron capture reaction ${\mathrm{Sc}}^{45}(n,\gamma ){\mathrm{Sc}}^{46}$ was utilized to populate low-lying states in ${\mathrm{Sc}}^{46}$ by means of $\gamma$-ray cascades from the compound-nucleus capture level. Scintillation singles and coincidence $\gamma$-ray spectroscopy techniques were used to study the gamma-ray decay characteristics of the levels observed. A rather complete set of data has been obtained for transitions between levels at excitation energies up to 0.675 MeV. Levels at 0.142, 0.225, 0.289, 0.445, 0.585, and 0.675 MeV have been inferred, and the decay characteristics of each of these states have been determined. In addition, many levels up to an excitation energy of 3.62 MeV have been observed and the principal $\gamma$-ray decay modes of these states are described. Conventional and time-to-pulse-height delayed-coincidence techniques were employed to establish the "prompt" ($t_{\frac{1}{2}}\lesssim 2\times {10}^{-9\mathrm{}}$ sec) lifetimes of the 0.225-, 0.289-, 0.445-, 0.585-, and 0.675-MeV states. The isomeric character ($t_{\frac{1}{2}}=20\mathrm{}$ sec) of the state at 0.142 MeV has been confirmed. A complete decay scheme for states up to an excitation energy of 0.675 MeV is proposed, and the observed characteristics of these levels are compared with previous ($d,p$) stripping studies and recent theoretical calculations. In addition, a decay scheme is also presented which involves states at higher excitation energies (≤3.62 MeV) and includes the $\gamma$-ray decay modes observed in the present work.