Cross Sections and Isomer Ratios for the Isomeric Pair ${\mathrm{Y}}^{90g}$ and ${\mathrm{Y}}^{90m}$ in the ${\mathrm{Rb}}^{87}(\alpha , n)$ and ${\mathrm{Y}}^{89}(d, p)$ Reactions

Excitation functions and cross section ratios for the isomeric pair ${\mathrm{Y}}^{90g}$ and ${\mathrm{Y}}^{90m}$ produced from ${\mathrm{Rb}}^{87}$ by ($\alpha , n$) reaction and from ${\mathrm{Y}}^{89}$ by ($d, p$) reaction were measured from 11-18 and 5-12 MeV, respectively. The isomer ratios produced in ($d, p$) reaction are approximately an order of magnitude smaller than those obtained by ($\alpha , n$) reaction; the total cross sections for both reactions are comparable. The differences in the isomer ratio curves are accounted for by differences in mechanism. The experimental isomer ratios obtained in the ($\alpha , n$) reaction are compared with the predicted values calculated in the manner of Huizenga and Vandenbosch. The results are discussed.