One of my samples that I have to characterize powder x-ray is an alloy ingot, but we don't have a proper sample holder for that kind of materials to be tested in our powder x-ray, we had some ideas of using clay as a zero background and bedding for the sample. but the results ended up being very noisy due to the inclusion of minerals in the clay. Do you guys know any good materials that would provide zero background in powder-Xray?
Typical zero background materials, that are used in powder X-ray diffraction if you have very little amounts of powder, are single crystals. They are cut in a way that the few specific directions, which fulfill the Bragg condition, are not reached by a theta/2theta scan on a 2-circle diffractometer.
However, I'm not sure if this is the zero background material that you are looking for. I guess your problem is rather the irregular shape of the solid sample than a small sample volume. In this case, I usually just press the sample into some plasticine with the top sample surface parallel to a flat plate below (e.g. powder sample holder) . However, plasticine scatters quite a lot. Thus, the plasticine must not be on the same height as the sample suface, but only around its bottom part. Make sure, that the beam is not larger than the sample by setting the slit openings accordingly.
If you want to embed the sample completely, as far as I know, there are amorphous epoxy resins, which I would prefer for crystalline samples, but there will always be some background.
Hi,
two examples of such crystals are Si(510) or (910) low background supports (see e.g. www.integratds.eu, e-mail:integra at integratds.eu).
We've always used silicon crystals which sound as if they're similar to those mentioned by Dusan Korytar. One word of warning with these: NEVER use them for an alkaline sample! Even quite mild alkali will damage them. Soluble carbonates definitely cause trouble, I'm wary about soluble bicarbonates.
Your alloy samples sound as if they're unlikely to be a problem in this respect... be careful you don't scratch the silicon, it's quite soft.
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