AbstractThe $γ $γ-ray strength function ($γ $γSF) and nuclear level density (NLD) have been extracted for the first time from inverse kinematic reactions with the Oslo method. This novel technique allows measurements of these properties across a wide range of previously inaccessible nuclei. Proton–$γ $γ coincidence events from the $\mathrm {d}(^{86}\mathrm {Kr}, \mathrm {p}γ )^{87}\mathrm {Kr}$d(86Kr,pγ)87Kr reaction were measured at iThemba LABS and the $γ $γSF and NLD in $^{87}\mathrm {Kr}$87Kr was obtained. The low-energy region of the $γ $γSF is compared to shell-model calculations, which suggest this region to be dominated by M1 strength. The $γ $γSF and NLD are used as input parameters to Hauser–Feshbach calculations to constrain $(\mathrm {n},γ )$(n,γ) cross sections of nuclei using the TALYS reaction code. These results are compared to $^{86}\mathrm {Kr}(n,γ )$86Kr(n,γ) data from direct measurements.