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- Sample composition - Quantitative analysis should be performed to identify the most accurate composition possible for the samples. This is the full composition for the sample, including any binder or support materials that may be present, not just the composition of the material of interest.
- Density - The density of the sample should be known in either g cm-3 or atoms Å-3.
- Packing fraction - This is a value between 0-1 and is often estimated to be ca. 0.6.
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- Have you simulated the pdf and the scattering data for comparison?
- Do you have .cif files that you can bring with you?
- Which of your samples are likely to be the most strongly scattering? This can be effected by the concentration of highly scattering elements, the crystallinity of the sample and the presence of large crystallites in your powder.
- Is your sample a "good" powder? Are there likely to be larger crystallites that need further grinding to give a good powder average?
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All samples should be labelled with the visit number and a suitable description of the material (i.e. the full composition including any support materials/binders) |
Know Your Setup
The vast majority of experiemnts on XPDF are run in glass capilaries that are supplied by the beamline. We offer both borosilicate and fused quartz capillaries in a range of sizes, outlined here. It is important that you do not pack your samples into different capillaries without discussing this with your local contact. Consistency is very important here in order for an accurate background subtraction to be made. Borosilicate capillaries are adequate for experiments where the sample will be at a temperatue < 500°C, otherwise for higher temperature experiments fused quartz capillaries should be used.
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