Fine Structure in theK-Series of Copper and Nickel and the Width of Spectral Lines

Width and fine structure of the $K{\alpha }_1$, $K{\alpha }_2$ and $K\beta$ lines of Ni, Cu, Mo and Ag.—High resolving power was obtained by means of the double x-ray spectrometer. The minimum width of slits was 1.75 mm. Wide slits made possible the study of the lines after second order reflection from two calcite crystals. Ionization currents were measured with a Compton type electrometer of sensitivity 5000 mm per volt at one meter. At 40 kv and in the first order the widths at half-maximum of the lines (in X.U.) were found to be: Ni $K{\alpha }_{1,2}$, 0.66; Cu $K{\alpha }_{1,2}$, 0.63; Mo $K{\alpha }_{1,2}$, 0.47; Ag $K{\alpha }_{1,2}$, 0.43; Mo $K{\beta }_{1,2}$, 0.43; Ag $K{\beta }_{1,2}$, 0.40. In the second order the estimated width of the components of Ni $K{\alpha }_{1,2}$ and Cu $K{\alpha }_{1,2}$ was 0.4 X.U. which was also the estimated width of Ni $K{\beta }_{1,2}$ and of Cu $K{\beta }_{1,2}$. Structure to the lines of nickel and copper was clearly indicated by the shapes of the curves. The first order curves of the $K\alpha$ lines of Ni and Cu showed an asymmetry on the long wave-length side which was checked as regards position and intensity by the second order curves. It was found that the lack of symmetry could be explained by the presence of weak lines at displacements 0.42 and 0.35 X.U. from Cu $K{\alpha }_1$ and Cu $K{\alpha }_2$, respectively, and 0.45 and 0.38 X.U. from Ni $K{\alpha }_1$ and Ni $K{\alpha }_2$, respectively. The $K\beta$ doublets of Mo and Ag were clearly resolved after first order reflection from two crystals. Their separations were, for Ag $K{\beta }_2-K{\beta }_1$ 0.63 X.U. and for Mo $K{\beta }_2-K{\beta }_1$, 0.58 X.U. These doublets for Ni and Cu were not resolved after second order reflection. However, the shapes of the curves obtained permitted a solution of the problem of intensities and displacements. Their separations were 0.32 X.U. and 0.29 X.U. for Cu $K{\beta }_2-K{\beta }_1$ and Ni $K{\beta }_2-K{\beta }_1$, respectively. The shapes of the $K\beta$ curves of Ni and Cu showed evidence of the spark line $K{\beta }^{\prime }$ and the curve of Cu showed evidence of a line...