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 ($\mathrm{Cu} K{\alpha }_1, \mathrm{Mo} K{\alpha }_1$) thereby establishing their wavelength relative to visible standards. In terms of the x-ray scale in which $\lambda \left(\mathrm{Cu}K{\alpha }_1\right)=1.537\mathrm{}400$ kxu, the conversion factor is ${\Lambda }_{\mathrm{Cu}}=1.002\mathrm{}0802$ Å/kxu (1 ppm); if $\lambda \left(\mathrm{Mo}K{\alpha }_1\right)=0.707\mathrm{}831$ kxu, ${\Lambda }_{\mathrm{Mo}}=1.002\mathrm{}1017$ Å/kxu (0.6 ppm).