checking diffractometer in capillary mode

[Natale Perchiazzi]

Dear All, I wonder which is the best way to check the performances of our lab diffractometer, working in capillary (transmission) mode. Our machine is a Bruker Vario with primary Ge monochromator and PSD detector. As a reference sample I prepared a 0.4 mm capillary carefully filled with SRM 676 alumina, and I use just this to check the zero and the intensity response of the instrument before the data collections. Moreover I periodically (3-4 months) perform an overnight scan up to 120° to get the instrumental profile coefficients to be subsequently used in my GSAS refinements.  What is your opinion on this topic? I would be moreover (very) interested in comparing scans of the SRM 676, made in the same experimental conditions, taken on instruments similar  to ours, so to have an idea of our "absolute" intensities and FWHMs.  Anybody interested?   Best regards       Natale Perchiazzi Dipartimento di Scienze della Terra Università di Pisa via S.Maria 53 56126 Pisa, Italia