High-resolution and high-intensity powder diffractometer at BL15XU in SPring-8

Area of Science:

• Materials Science
• Crystallography
• Synchrotron Radiation Physics

Background:

• High-resolution powder diffraction is crucial for understanding material structures.
• Existing diffractometers may lack the necessary resolution or flux for complex analyses.
• Advancements in synchrotron radiation sources enable new experimental capabilities.

Purpose of the Study:

• To introduce a newly constructed ultra-high-resolution powder diffractometer at SPring-8's BL15XU beamline.
• To detail the instrument's design, optimization for high-flux and coherent X-ray beams, and adaptable optical configurations.
• To demonstrate the diffractometer's capability for precise structural refinement of materials.

Main Methods:

• Construction of a two-axis diffractometer optimized for synchrotron radiation.
• Implementation of transmission and reflection geometries with capillary and flat-plate specimens.
• Utilizing a planar undulator and Si(111) double-crystal monochromator for beam conditioning.
• Employing a 2theta step-scan technique with various optical configurations, including Ge(111) or Si(111) analyzers and parallel slits.
• Conducting Rietveld analysis on high-resolution powder diffraction data.

Main Results:

• Achieved a minimum full width at half-maximum of 0.00572 degrees (2theta) for Si powder reflections.
• Demonstrated successful refinement of 288 structure parameters for a zeolite ZSM-5 sample using Rietveld analysis (Rwp = 6.96%).
• The diffractometer operates over a wide temperature range (32–900 K) using a He/N(2) gas stream system.

Conclusions:

• The new ultra-high-resolution powder diffractometer is a powerful tool for advanced materials characterization.
• The instrument's design and capabilities allow for detailed structural analysis of complex materials.
• High-precision structural refinement, as shown with zeolite ZSM-5, is achievable with this new setup.