Attached file show's the unreal peaks in deferent positions for same sample SI SUBSTR with 0 background measured many times.
Dear Mohamed Ali Naser ,
to my opinion these 'peaks' are not due to x-ray diffraction; they are too narrow for real diffraction lines.
It seems to me, that you have got a malfuction of your detector system, e.g. some EM-interference with surrounding electric/electronic equipment.
a) Sparking of defect starters of neon tubes may induce such spikes in your XRD pattern... Please have a look for example in (or around) your lab for a 'blinking' neon tube...
b) You should also check (install) the electrical grounding*) of your experimental set up; especially that of the x-ray tube and that of the detector.
c) You may operate your system at lower tube voltages and see what is happening now (sparking may arise**) from the HV of the tube)
*) but, avoid grounding loops
**) in the case of a defect system
Best regards
G.M.
They seem scatter, they are not diffraction peaks, they seem single points higher than the background. It could be a problem of the x-ray detector
@ Jp Wu Yes preferred orientation effects are possible but also in this case we expect peaks with a FWHM, not single points. In addition, the sample is the same measured many times, so the pattern should be the same.
But Jp Wu ,
what was your real peak width?
Also only one (or at maximum two 2theta readings)?
I guess, that in your case the peak withs were a bit wider and their positions closely coincide with the peak positions of a powdered sample of the same type.
In the case of Mohamed Ali Naser 's pattern, the 'peaks' are extremely narrow and there are in total a lot of positions; they are quite randomly distributed in 2theta. But only a very few of them match the positions of Si peaks.
Si has got only three major lines:
see for example: https://rruff.info/Silicon
(scroll a bit down to see the powder pattern)
One might think, that the step width in Mohamed Ali Naser 's pattern is too large in order to grasp the peaks by more than one 2theta position; but when looking at the background noise, one can see at the step with is small enough to get peaks with a real profile/shape.
Best regards
G.M.
Too small FWHM can also be due to relatively larger data acquisition steps. In my case, only some, not all diffraction peaks correlate to the crystalline structures. Once a proper and the same sample preparation approach was implemented pre-xrpd, the peaks are consistant and repeatable regatding peak positions.
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