> > I have always found more useful having LaB6 or corundum
Fabrizio's question "why use silicon powder" might have been answered more precisely, and in much less than 64 ko (~64,000 letters :-) as follows: The line width of the NIST Si powder sample 640e is no better than the NIST sintered corundum disk 1976b, which is also slightly cheaper at $680. The best NIST x-ray standard is however LaB6 powder 660c, which is 50% more expensive; the line widths of the other two are 50% greater. The recipe for making a silicon disk from powder is interesting, but why bother if you can buy the sintered Al2O3 disk, if indeed you want a disk rather than powder. Alan ______________________________________________ * Dr Alan Hewat, NeutronOptics, Grenoble, FRANCE * <alan.he...@neutronoptics.com> +33.476.98.41.68 http://www.NeutronOptics.com/hewat ______________________________________________
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