Yield Ratios for the Isomeric Pair Sc44m,44 Formed in (α, αn) and (α, n) Reactions

Abstract

The yield ratio of ${\mathrm{Sc}}^{44m}/{\mathrm{Sc}}^{44}$ was measured in ${\mathrm{Sc}}^{45}(\alpha , \alpha n){\mathrm{Sc}}^{44}$ reactions with helium ions of energies between 20 and 43 Mev and at 320 Mev. The measured ratio was nearly constant at a value of 1.5 between 20 and 43 Mev and was 0.62 at 320 Mev. The ${\mathrm{Sc}}^{44m}/{\mathrm{Sc}}^{44}$ ratio was measured in ${\mathrm{K}}^{41}(\alpha , n){\mathrm{Sc}}^{44}$ reactions at 10 and 43 Mev with values of 0.3 and 0.9, respectively. The isomer ratio was calculated for the ${\mathrm{K}}^{41}(10-\mathrm{Mev} \alpha , n){\mathrm{Sc}}^{44}$ reaction by means of a compound-nucleus model, and for the ${\mathrm{Sc}}^{45}(320-\mathrm{Mev} \alpha , \alpha n){\mathrm{Sc}}^{44}$ reaction by means of a classical knock-on model. The calculated ratios were 0.32 and 0.51, respectively.