Hello all,
I'm trying to fit an XRD scan of a silicon powder, but I'm having some trouble getting the peak profile right. Usually, I use the fundamental parameters method in Topas and add a crystallite size broadening function. However, that did not work at all for this material, so I tried the built-in peak shape functions in Topas, PV, TCHZ and PVII. The last one does best in terms of overall fit, but I worry that it is capturing a lot of the background into the long peak tails. This seems troublesome because I'm trying to get an accurate value for the scale factor. Does anyone have any comments, or general recommendations on how to choose a suitable peak profile? There seem to be a lot of options available and I have trouble picking those which fit the data well but also physically make sense. Thank you!
Note the Y-axis units are sqrt(int) for better visibility of the peaks & background.