Analysis of long‐range order

Mosaicity, topography, and reciprocal‐space mapping are all techniques to probe the physical characteristics of the crystals through their interaction with X‐rays. The techniques described are complementary. In terms of structural crystallography, i.e. solving and understanding the structure of a macromolecule of interest, having a high‐quality crystal is clearly desirable. The techniques described here are not part of routine data collection. Of the techniques described, mosaicity measurements can be performed relatively easily and are the most immediately useful. The quality of the data can...

Mosaicity, topography, and reciprocal‐space mapping are all techniques to probe the physical characteristics of the crystals through their interaction with X‐rays. The techniques described are complementary. In terms of structural crystallography, i.e. solving and understanding the structure of a macromolecule of interest, having a high‐quality crystal is clearly desirable. The techniques described here are not part of routine data collection. Of the techniques described, mosaicity measurements can be performed relatively easily and are the most immediately useful. The quality of the data can be optimized by matching the oscillation range to the mosaicity. The background noise in an oscillation image builds up throughout the oscillation range but the reflection is only recorded over a finite angle. In the future “ideal” data collection may be possible by continuous rotation with real‐time detector readout offering effectively infinitely fine slicing.