Cross sections for the formation of ${}_{}{}^{79}{}_{}{}^{}\mathrm{Br}_{}^{\mathit{m}}{}_{}{}^{}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}_{}^{\mathit{m}}{}_{}{}^{}$, and ${}_{}{}^{95}{}_{}{}^{}\mathrm{Tc}_{}^{\mathit{m}}{}_{}{}^{}$ nuclear states respectively through the reactions ${}_{}{}^{79}{}_{}{}^{}\mathrm{Br}$(n,n’${)}^{79}$${\mathrm{Br}}^{\mathit{m}}$, ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$(n,n’${)}^{90}$${\mathrm{Zr}}^{\mathit{m}}$, and ${}_{}{}^{96}{}_{}{}^{}\mathrm{Ru}$(n,n’p${)}^{95}$${\mathrm{Tc}}^{\mathit{m}}$ induced at 14 MeV neutron energy are measured in the laboratory using ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$(n,α${)}^{24}$Na as the reference reaction. The measured cross-section values (40±3 mb for ${}_{}{}^{79}{}_{}{}^{}\mathrm{Br}_{}^{\mathit{m}}{}_{}{}^{}$, 615±28 mb for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}_{}^{\mathit{m}}{}_{}{}^{}$, and 135±8 mb for ${}_{}{}^{95}{}_{}{}^{}\mathrm{Tc}_{}^{\mathit{m}}{}_{}{}^{}$) are in good agreement with the corresponding theoretical values (40 mb for ${}_{}{}^{79}{}_{}{}^{}\mathrm{Br}_{}^{\mathit{m}}{}_{}{}^{}$, 584 mb for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}_{}^{\mathit{m}}{}_{}{}^{}$, and 137 mb for ${}_{}{}^{95}{}_{}{}^{}\mathrm{Tc}_{}^{\mathit{m}}{}_{}{}^{}$) estimated with compound nucleus theory and by assigning the isomer ratio in the limit 2 to 5 of the spin distribution factor. Probabilities for decay of excited nucleus to metastable and ground states via various possible spin states were calculated using a partial wave analysis method, an illustration of which is provided with an example of the reaction ${}_{}{}^{115}{}_{}{}^{}\mathrm{In}$(n,2n${)}^{114}$${\mathrm{In}}^{\mathit{m}}$. This method enables calculation of the isomer ratio even if the ground state of the nucleus is not radioactive.

• Received 12 August 1992

DOI:https://doi.org/10.1103/PhysRevC.46.2246