X-ray Diffraction: Four-Circle
Quick Specs
- Principal application for analyisis of epitaxial thin film
- Normal operating power of 45 kV, 40 mA
- Supports monolithic specimens of a wide variety of shape and size
Resources
- American Mineralogist Crystal Structure Database
- Anton-Paar
- Bede X-ray Metrology
- Collaborative Computational Project Number 14 (CCP14) for Single Crystal and Powder Diffraction
- International Centre for Diffraction Data
- International Union of Crystallography
- Materials Data Inc.
- Mineralogy Database
- PANalytical (formerly Philips Analytical)
- WWW-MINCRYST
Three X-ray diffraction (XRD) systems are available for analysis of crystalline materials:
- General purpose XRD system for phase analysis of polycrystalline samples
- Special applications XRD system with high- and low-temperature sample stages, plus focusing and parallel beam optics
- Four-circle XRD system with high-resolution optics (HRXRD, Double Crystal, or Triple-Axis geometry) for studying large-face single crystals and epitaxial thin films.
System Configurations and Operational Overview
All work with the following systems and in EMSL labs must be performed in compliance with EMSL practices and permits.
The four-circle X-ray diffractometer is a Philips X'Pert MRD PRO system with a horizontal, high-resolution Ω-2Θ goniometer (320 mm radius). An open Eulerian cradle provides two additional axes of rotation (-90° < ψ < 90°, and -360° < Φ < +360°). The X-ray source is a long-fine-focus, ceramic X-ray tube with Cu anode. Normal operating power is 45 kV, 40 mA (1.8 kW). The sample stage supports monolithic specimens of a wide variety of shapes and sizes.
The incident-beam optic is a line-focus Hybrid monochromator. The Hybrid combines a Göbel mirror with a 4-bounce Ge(220) monochromator to provide an intense, highly collimated beam (ΔΘ ~ 25 arc seconds). The typical receiving optic is an open Xe proportional counter detector with a receiving slit (high-resolution or double-crystal x-ray diffraction). Alternatively, the detector can be placed behind the Triple-Axis Ge(220) analyzing crystal (Δ2Θ ~ 12 arc seconds). The principal application of this setup is structure analysis of epitaxial thin films (rocking curve measurements, etc.).
Analysis Software
The principal XRD data analysis program is JADE (Materials Data Inc., Livermore, CA.). JADE supports comprehensive analysis of XRD patterns, including phase identification, peak profile fitting, indexing, unit cell refinement, Rietveld analysis, etc. Available software for thin film applications includes the Bede programs RADS and REFS, plus the Philips programs X'Pert Texture, X'Pert Epitaxy, and WINGIXA.
Reference Database
The principal reference database is the Powder Diffraction File (International Centre for Diffraction Data, Newtown Square, PA.).
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