Journal of Applied Crystallography

Volume 37, Part 3 (June 2004)

short communications

J. Appl. Cryst. (2004). 37, 481-485 [ doi:10.1107/S0021889804004303 ]

First results of digital topography applied to macromolecular crystals

J. J. Lovelace, A. S. Soares, H. D. Bellamy, R. M. Sweet, E. H. Snell and G. E. O. Borgstahl

Abstract: An inexpensive digital CCD camera was used to record X-ray topographs directly from large imperfect crystals of cubic insulin. The topographs recorded were not as detailed as those which can be measured with film or emulsion plates, but do show great promise. Six reflections were recorded using a set of finely spaced stills encompassing the rocking curve of each reflection. A complete topographic reflection profile could be digitally imaged in minutes. Interesting and complex internal structure was observed by this technique. The CCD chip used in the camera has anti-blooming circuitry and produced good data quality, even when pixels became overloaded.

Keywords: topography; crystal quality; reflection profiles; mosaicity; digital imaging; image processing.