X-Ray to Visible Wavelength Ratios

Abstract

The lattice repeat distance of a nearly perfect single crystal of silicon has been measured in terms of the visible wavelength of a stabilized He-Ne laser. This crystal subsequently has been used to diffract reference x-ray lines ($\mathrm{Cu} K{\ensuremath{\alpha}}_{1}, \mathrm{Mo} K{\ensuremath{\alpha}}_{1}$) thereby establishing their wavelength relative to visible standards. In terms of the x-ray scale in which $\ensuremath{\lambda}(\mathrm{Cu}K{\ensuremath{\alpha}}_{1})=1.537400$ kxu, the conversion factor is ${\ensuremath{\Lambda}}_{\mathrm{Cu}}=1.0020802$ \AA{}/kxu (1 ppm); if $\ensuremath{\lambda}(\mathrm{Mo}K{\ensuremath{\alpha}}_{1})=0.707831$ kxu, ${\ensuremath{\Lambda}}_{\mathrm{Mo}}=1.0021017$ \AA{}/kxu (0.6 ppm).