International
Tables for
Crystallography
Volume H
Powder diffraction
Edited by C. J. Gilmore, J. A. Kaduk and H. Schenk

International Tables for Crystallography (2018). Vol. H, ch. 2.6, pp. 154-155

Section 2.6.8. Temperature accuracy

C. A. Reissa*

aNoordikslaan 51, 7602 CC Almelo, The Netherlands
Correspondence e-mail: Celeste.Reiss@PANalytical.com

2.6.8. Temperature accuracy

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The accuracy of the temperature measurement of a non-ambient device has to be determined before starting a non-ambient experiment. At present no certified temperature standards for X-ray powder diffraction are available, only commonly used reference materials. A list of these materials can be found at https://www.xrayforum.co.uk/ and https://bl831.als.lbl.gov/~jamesh/pickup/Snell_SG_change_table.pdf .

A common method for validation of a non-ambient chamber is by determining the thermal expansion coefficient of a reference material as a function of temperature. Another is to determine the transition temperature of well known phase transformations. A third method is the so-called `differential thermal expansion' method (Drews, 2001[link]). This method utilizes the relative thermal expansion of two diffraction peaks. These peaks can be from the same or different reference material(s) but must be found in a narrow angular range and have different thermal expansion behaviour. Using only the relative separations of the peaks that are closely spaced eliminates the need for full pattern refinement to take into account geometrical aberrations and makes this method fast.

References

Drews, A. R. (2001). Calibration of a high temperature X-ray diffraction stage by differential thermal expansion. Adv. X-ray Anal. 44, 44–49.Google Scholar








































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