Related Experiment Video
Updated: Jul 31, 2026

High Pressure Single Crystal Diffraction at PX^2
Published on: January 16, 2017
Practical considerations on the determination of the accuracy of the lattice parameters measurements from digital
Johannes Biskupek1, Ute Kaiser
1Friedrich-Schiller-University, Institute of Solid State Physics, Helmholtzweg 5, D-07743 Jena, Germany. biskupek@pinet.uni-jena.de
Abstract:
The influence of magnification and defocus on the precision Delta d/d of lattice parameter measurements have been studied by evaluating the diffraction vector length and the signal-to-noise ratio (SNR) of the diffraction peaks in diffractograms calculated by fast Fourier transformation (FFT) of digitally recorded images. Examples are perfect crystals (Si and SiC) and defective crystals (two- and three-dimensional defects within SiC). It is shown that the precision is independent of the diffuseness of the FFT reflections caused by defocus changes or by two-dimensional defects. For the case of a perfect and/or a defective but unstrained crystal, the precision Delta d/d is linearly dependent on the diffraction vector length. For optimal conditions, the highest precision is 0.002. For a defective crystal containing precipitates (nanocrystals), it was found for both the matrix and the nanocrystals that the precision of the measurement is determined by the contribution of strain value (Delta d/d)(strain) of the defective crystal and accuracy Delta d/d for the perfect matrix crystal.
Related Concept Videos
X-ray Crystallography
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
X-ray Diffraction of Biological Samples
According to Bragg's law, when X-rays strike the sample positioned on a stage, the rays are scattered by the electron clouds around the sample atoms. The X-ray diffraction or scattering is caused by constructive interference of the X-ray waves that reflect off the internal crystal...
Determination of Crystal Structures

