On high-resolution reciprocal-space mapping with a triple-crystal diffractometer for high-energy X-rays

Area of Science:

• Materials Science
• Condensed Matter Physics
• Crystallography

Background:

• High-energy X-ray diffraction is crucial for characterizing bulk material defects.
• Triple-crystal techniques offer enhanced resolution for analyzing strain and dislocations.

Purpose of the Study:

• To describe a triple-crystal diffractometer for high-energy X-ray diffraction.
• To investigate the influence of crystal reflection choice and sample orientation on resolution.
• To demonstrate the analysis of reciprocal-lattice distortions.

Main Methods:

• Utilizing a triple-crystal diffractometer at the European Synchrotron Radiation Facility (ESRF) High Energy Beamline.
• Employing high-energy X-rays (typically > 80 keV) for low attenuation and high momentum transfer resolution.
• Analyzing Bragg reflection satellites and reciprocal-lattice distortions in a silicon single crystal.

Main Results:

• Demonstrated the dependence of transverse and longitudinal resolution on crystal reflection selection.
• Showcased how sample orientation relative to the instrument's resolution element impacts defect analysis.
• Observed satellite reflections around the Bragg peak in a silicon crystal with a macro pore layer, indicating longitudinal distortion.

Conclusions:

• High-energy X-ray diffraction with triple-crystal methods is powerful for studying dislocations and strain.
• Optimizing crystal reflections allows for detailed investigation of longitudinal distortions using the instrument's high transverse resolution.
• The orientation of lattice distortions is critical for effective analysis with this technique.