research papers
The scattering of X-rays by parallel layers in disordered stacking is calculated, taking account of the number of layers per stack. The result is a more general formula than that obtained by Hendricks & Teller for random stacks of an infinite numbers of layers. Systems with complete or partial randomness are discussed. The latter case comprises crystals with `mistakes'. The influence of the nature of the mistakes (accidental shifts, or twinning along certain planes), is studied, as is also the influence of their distribution.