Geometrical Factors Affecting the Contours of X-Ray Spectrometer Maxima. I. Factors Causing Asymmetry

The observed asymmetry of x-ray spectrometer maxima arises principally from three-dimensional properties of the ideally two-dimensional focusing arrangement employed, vertical divergence of the primary beam being the fundamental cause. A mathematical formula is developed that expresses the degree of asymmetry as a function of the reflection angle and the geometrical properties of the apparatus. The asymmetrical effects predicted in this way are qualitatively confirmed with experimental measurements. Practical suggestions are made for minimizing asymmetry.