Artificial layered structures that produce sharp diffraction of x rays are described. The structures were made by alternately evaporating 140 Pb and Mg layers onto a glass slide (d=27 Å). The diffracting efficiency of the layered structures is compared with other structures used in soft x-ray spectroscopy. The usefulness of the structures is limited by diffusion in the layered system which caused the diffraction pattern to decay to half intensity in 2 days at room temperature. At 0°C the half life was 5 weeks. The diffusion model of DuMond and Youtz was used to determine an effective diffusion constant for the system over the temperature range 0–62°C. The equation Deff=5.2×10−6 exp(−20 600/RT) cm2/sec was satisfied.

Five orders of soft x-ray diffraction by multilayered thin-film structures of Fe and Mg have been observed. The structures consisted of as many as 200 layers of Fe separated by Mg layers, providing layer spacings of 30–50 Å. The diffracting characteristics have been measured for the wavelength range 8.34 to 23.7 Å (AlKα to OKα). The integrated diffracted intensities from Fe–Mg layered structures and multilayered lead stearate soap-film structures are shown to be comparable. A diffracted x-ray peak intensity to background ratio of 80 and a resolution (λ/Δλ) of 25 have been observed for the diffraction of OKα radiation by the Fe–Mg structures. No diffusion in the Fe–Mg layers was detected at room temperature. The diffracted x-ray intensity from similar Au–Mg layered structures decreased to one-half in 15 days at room temperature because of interdiffusion. Diffusion in the Au–Mg layered system may be described by an effective interdiffusion constant that satisfies the equation Deff=4.3×10−9 exp[−18.3 kcal/(RT)] cm2 sec−1 for the temperature range 23–100°C. For Fe–Mg layered structures an effective interdiffusion constant Deff=7.9×10−20 cm2 sec−1 was measured at 260°C.