Reinvestigation of the gamma branch from theU238shape isomer

The $\gamma$-ray decay of the $J^{\pi }=0^{+}$ shape isomer at 2557.6 keV of excitation in ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ has been reinvestigated using the ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}\mathrm{}(\mathrm{d},\mathrm{p}\mathrm{n})\mathrm{}{}_{}{}^{238}{}_{}{}^{}\mathrm{U}_{}^m{}_{}{}^{}$ reaction with a new two-detector technique. A line at 2512.7±0.5 and another possible one at 1877.6 keV are attributed to decay of the isomer. The cross section for production of the 2512.7-keV $\gamma$ ray by 18-MeV deuteron bombardment of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ is 42±12 μb, consistent with our earlier conversion-electron work on ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}_{}^m{}_{}{}^{}$. The isomer decay is about 5% by fission and 95% by $\gamma$ rays and conversion electrons.