The ${}^{93}\mathrm{Nb}$($t,{}^3\mathrm{He}$) reaction at 115 MeV/nucleon was studied to demonstrate that nuclear level densities and $\gamma$-ray strength functions can be extracted from charge-exchange reactions at intermediate energies using the Oslo technique. The matrix of excitation energy in ${}^{93}\mathrm{Zr}$, reconstructed from the ($t,{}^3\mathrm{He}$) reaction, versus the energy of $\gamma$ rays emitted by the excited ${}^{93}\mathrm{Zr}$ nuclei, was obtained in an experiment with the S800 Spectrograph operated in coincidence with the GRETINA $\gamma$-ray detector. The extracted level density and $\gamma$-ray strength function obtained by applying the Oslo method to this matrix were used to estimate the ${}^{92}\mathrm{Zr}(n,\gamma ){}^{93}\mathrm{Zr}$ cross section by combining the new results with other experimental data and theoretical calculations for $E1$ and $M1$ strength functions at higher energies. Good agreement with direct measurements of the ${}^{92}\mathrm{Zr}(n,\gamma ){}^{93}\mathrm{Zr}$ cross section was found. The contribution from the upbend in the extracted $\gamma$-ray strength function was important to achieve the consistency, as the neutron-capture cross section without this contribution is significantly below the direct measurements otherwise. Since charge-exchange reactions at intermediate energies have long been used for extracting Gamow-Teller strengths, the successful demonstration of the charge-exchange Oslo method enables experiments in which ($n,\gamma$) cross sections and Gamow-Teller strengths can be measured simultaneously, which is of benefit for astrophysical studies.

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• Charge-exchange reactions
• Gamma-ray strength functions
• Level densities
• Nuclear astrophysics
• Nuclear reactions
• Nuclear structure & decays
• Radiative capture
• 90 ≤ A ≤ 149