The effects of instrumental distortion in X-ray diffraction studies of liquids. II. Collimation distortion

The effects of collimation distortion on the measured diffraction curves from `amorphous' solids and liquids are discussed. It is shown how the parameters governing the range of angular divergence may be obtained and how the `permissible' range of scatter angles may be established. Model calculations and experiments were performed to show some of the distortion effects which can occur in the measured interference function if the permissible range of scatter angles is exceeded. It is shown that distortion effects are potentially most severe where line sources are employed, and it is therefore recommended that in future, collimation limits are calculated and stated. If it proves necessary to use collimation limits which distort the data in order to achieve satisfactory intensity, then these limits should be chosen so that analytical correction procedures to correct the data are possible.