Kα1andKα2X-Ray Energies of Neptunium, Plutonium, and Americium

The $K{\alpha }_1$ and $K{\alpha }_2$ x-ray energies of Np, Pu, and Am have been measured with a Cauchois-type bent-crystal transmission spectrometer. The energies of these transitions have been determined to an accuracy of 5 eV. The $K{\alpha }_1-K{\alpha }_2$ differences agree within the experimental error with differences obtained from the previously reported $L$ x-ray energies.