Widths of theKα1andKα2X-Ray Lines forZ>50

A Cauchois-type transmission bent-crystal spectrometer has been used to measure the full width at half-maximum of the $K{\alpha }_1$ and $K{\alpha }_2$ x rays of 36 elements from ${}_{51}{}^{}{}_{}{}^{}\mathrm{Sb}$ to ${}_{95}{}^{}{}_{}{}^{}\mathrm{Am}$. The x-ray lines were fitted by folding a Lorentzian natural line shape with a Gaussian instrumental response and integrating over the detector-slit width. The present results are systematically somewhat higher than the values deduced from recent theoretical calculations of the radiative widths and the appropriate experimental fluorescent yields.