X-Ray Diffraction and Diffusion in Metal Film Layered Structures

Abstract

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 D_eff=5.2×10⁻⁶ exp(−20 600/RT) cm²/sec was satisfied.