The mosaic spread of very small crystals deduced from Laue diffraction patterns

Laue diffraction patterns have been recorded with synchrotron radiation for some very small crystals; in most of them the reflections are elongated radially. The Laue geometry is particularly sensitive to mosaic spread, and a relationship between mosaic spread and Laue spot extension is deduced. It appears that many very small crystals have a large mosaic spread (0.5-1° or more) which is probably the reason why they did not grow bigger.