PPT Slide
The first Geiger-counter diffractometers were used in 1945 and these allowed data of sufficient precision to be recorded for QA.
Absorption: When a mixture contains both a weak and a strong absorber, lines of the weak absorbing compound appear weaker (and those of the strong absorbing compound stronger) than calculated from a linear relationship between pattern intensity and composition.
In 1948 Alexander and Klug gave the theoretical mathematical background for the effects of absorption on diffracted intensities from a flat powdered cake. Many developed methods have used their basic equations.