Hi all I've collected some more data, and am still getting spurious results, and by spurious, I mean -5 wt% amorphous in SRM-alpha-656 when quantified by the external method against SRM 676a.
We had some SRM-656alpha (couldn't find any of the beta) stored in a drying oven, and some SRM676a stored in a cupboard. I collected some data using a D8 with Ni-filtered Cu and a lynx-eye detector (0.25° fixed divergence, 250 mm radius, 2x2.5° sollers). The patterns were collected consecutively (using the same program), with a single peak from SRM1976 (b, I think), acting as an intensity calibrant (the intensity didn't appreciably change), collected before, after, and between. Does anybody want to have a look at the data and see what I'm doing wrong? Data available at: https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_676a.xy https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_al656.xy Thanks Matthew On Wed, 16 Mar 2022 at 21:13, Matthew Rowles <rowle...@gmail.com> wrote: > Hi List People > > Do any of you use NIST SRM656 in your quantitative analysis quality > control? > > I've recently started at a new lab, and am finding it impossible to make a > physically realistic model (in Topas) that gives results anywhere near > correct (or at least, close to the certificate values). > > As an example, using the external std approach with SRM676, I've managed > to calculate there is -11 wt% amorphous in the beta-656 standard. > > I've tried using the silicon nitride structures given in the SRM > certificate, but the papers and the ICSD entries don't list any thermal > parameters. > > I can get the same results as given on the certificate using a siroquant > model, but I don't know the provenance of the HKL files used in the > analysis. > > > Thanks in advance > > > Matthew Rowles >
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