When measuring PXRD for a thin film or powder sample I get strange peak shapes when using a Ge(220)x2 monochromator compared to using a soller slit. I am using a Rigaku Smartlab PXRD, measuring in Parallel Beam mode. The Ge(220)x2 is denoted for high resolution and often used here for thin film reflectivity or lattice mismatch detection. When I attempt to use this same method for other types of samples the spectra comes out completely strange. Is there a reason for this? Does the Ge(220)x2 method not work for standard powder or drop cast type samples?
Did you adjust the diffractometer properly after mounting the monochromator?
Did you run standard sample before and after setting up the incident beam geometry?
After mounting I aligned optics. (automated system) Then aligned the sample (also automated).
No standard was run. But I can try that.
If "Ge(220)x2 monochromator " is a channel-cut monochromator: Although I saw once reasonable data from a "powder" from such a setup, I would discourage use of a channel-cut monochromator for diffraction on polycrystalline speciemens. You will have very poor crystallite statistics and hence you can get a lot of artifacts. If you have nanocrystals, you will not profit from the resolution, and if you have not nanocrystals, you will have a too poor statistics. A channel-cut monochromator has not been designed for such a purpose.
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