Gamma-Rays from the Reaction ${\mathrm{H}}^1(n,\gamma )D^2$ and the Binding Energy of the Deuteron

The binding energy of the deuteron has been determined directly as 2.230±0.007 Mev by measuring the energy of the gamma-radiation from the reaction ${\mathrm{H}}^1(n,\gamma )D^2$. The energy of this gamma-radiation was compared with that of the 2.615-Mev gamma-ray of ThC" by a spectrometer study of the photo-electrons ejected from a thin uranium radiator. The probable error of 0.007 Mev includes a probable error of 0.004 Mev in the energy of the ThC" gamma-ray.