For micro-structure analysis (Rietveld refinement), I know the instrument resolution file (IRF) is necessary to get anisotropic strain and size effects in Fullprof (Npr=7). To get the IRF of the XRD equipment where I made the measurements: Is it necessary to make all the process of measuring a standard sample Lab6 and its refinement? or only I download an IRF file from the internet and change some parameters?. I made my XRD measurements in X’Pert Pro-MPD equipment (Bragg–Brentano θ–2θ configuration).