Non-Laue Maxima in the Diffraction of X-Rays from Rocksalt—Temperature Effect

No previous quantitative measurements have been made of the temperature dependence of the non-Laue diffraction maxima at lowered temperatures, although it has been known that the non-Laue diffraction pattern of many crystals nearly disappears at liquid-air temperature. In the present experiment, an ionization chamber and electrometer tube circuit have been used in determining the intensity of the non-Laue maxima observed when copper $K\alpha$ x-rays are diffracted from a rocksalt crystal. Measurements have been made at room temperature and at liquid-air temperature for the 200, 400, and 600 regions of scattering. It is found that the experimental decrease in intensity at liquid-air temperature is in fair agreement with an expression of the form ($1-e^{-2M}$), where $e^{-2M}$ is the well-known Debye-Waller temperature factor.