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Figure 11
These are the calculated distributions of the integrated intensities at 2θBn = 30° with Cu Kα1, for a set of crystal planes in random orientations, for three crystal sizes. The maximum intensity (the rightmost data point in each histogram) corresponds to the Bragg condition, Ω = θBn. The mean intensity gives a good representative parameter for the total scattering from these planes. The `true mean' (red line) associated with the total scattering is approximately constant for perfect and imperfect crystals (σ = 0.25°) for all crystal sizes (∼3% fall in intensity). If the intensity is just captured near the peak over two orders of magnitude the mean values fall, and the structure factor is underestimated by 2% for perfect crystals and 3% in imperfect crystals. If the data are only captured over one order of magnitude, then the structure factor is underestimated by 5% for perfect crystals and by 20% for imperfect crystals (the green line in the figure). This calculation includes 5 000 000 orientations to ensure the profile is fully converged.

ISSN: 2053-2733
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