Hello everyone
2-3 months I start getting weird XRD diffractograms. I was performing locked couple analysys on some polycrsitalline films. I am analysing those films for years so I know them quite well-. I am interested in some stress measurements so I was focusing on some Locked coupled spectra. This time I got peaks with huge intensities for a certain theta positions. I start analysing only the substrates and the peak are still there (mgO and Quartz - see the pictures; I get same results for Si or Al2O3 substtrates). Moreover, I performed LC on the empty sample holder (that should be zero background) and surprise the peaks are still there. It might be a contamination but the FHWM lead to very crystalline phases. It seems to be Aluminium or Titanium. Any idea about the sources of this peaks? Any solution. I had same problem 5 6 years ago on the same machine but that dissapeared by itself after a while. Now the problem is lasting.
This is a very interesting problem. Let me begin with the basics. After collimation, there is a diffraction parallelogram: all that you "see" in the diffraction pattern must be "touched" by the diffraction parallelogram. If collimation is too large, also the diffraction parallelogram volume is. Can you minimize the collimation? Can you move the "focus" of the diffraction beam?
For the moment these are my first suggestions.
Dear Petru Lunca-Popa ,
we can only speculate here.
The fact that you 'see' diffraction peaks leads to the assumption of a collimation issue, as P. Grima Gallardo indicates above.
The fact that you have had such 'troubles' in the past and that they disappeared by their own, let me think on a handling error.
What is about an unintended switching between the 'line' and the 'point' focus operation of the x-ray tube or vice versa...
Best regards
G.M.
Thank you for your suggestion. I will try it tomorrow. However, I forgot to mention that the grazing incidence scans (0.5 deg) are Ok.
This version is having only the line focus option. The " point" focus is done by adding a snout - cilinder arround 15 cm long and with small aperture.
Petru Lunca-Popa The normal routes to resolution are via the 3M's approach (Machine, Method, Material). Either the machine isn't working for some reason, the method is suspect or not robust, or there is heterogeneity in the material providing different (but each correct) answers
- Run a standard material whose performance is known and certified. This will either confirm or deny the instrument performance
- Contact the manufacturer or local support. I suspect that this is trivially easy in Europe. An applications or service engineer will be able to take it forward from there
Hello and thank you for the interest concerning my problem. As described above I already run standard materials (such as Al2O3 MgO ) and the peaks are still there. So the problem is not material related. Especially when the peaks are present even in the absence of any material
We contact the support and they are looking.
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