The Absorption Displacement in X‐Ray Diffraction by Cylindrical Samples

摘要

In the precision determination of lattice constants from back reflection Debye‐Scherrer patterns, one of the systematic errors arises from the effect of absorption in the sample. The magnitude and form of the error is calculated for a cylindrical sample, for both parallel and diverging primary beams, and for a representative variety of values of the absorption coefficient. Calling 2φ the back scattering angle (φ=90-θ), it is found that the error in φ caused by absorption can be set proportional to φ. The form of the absorption correction allows it to be lumped in with the other systematic errors for a linear extrapolation according to either Δd/d =Kφ tan φ or Δd/d=K sin2 φ. There is some preference for the former.