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The Panalytical X'Pert Diffractometer is a highly advanced, versatile materials characterization system. Interchangeable PreFIX incident and diffracted beam optics can be configured for optimal measurement of high resolution scans, reflectivity experiments, or for in-plane diffraction.
High Resolution X-ray Diffraction: High resolution x-ray diffraction is generally applied to highly ordered crystals. It is useful to examine nearly lattice matched materials or the structural perfection of materials. The system can be used to accurately measure the width of Bragg diffraction peaks from nearly perfect single crystals over the range of a few seconds of arc. In order to obtain the high resolution, the angular divergence of the incident x-ray beam must be very small with little or no peak broadening due to spectral dispersion and the goniometer must be capable of very accurate stepping. Special incident and diffracted beam conditioning makes this possible. This system can also map regions in reciprocal space around the Bragg reflections which can be useful to characterization relaxation of strained epitaxial films.
Reflectometry: Reflectometry is an analytical technique for investigating thin layers. In reflectivity experiments, the X-ray reflection of a sample is measured around the critical angle. Below the critical angle of total external reflection, X-rays penetrate only a few nanometers into the sample. Above this angle the penetration depth increases rapidly. At every interface where the electron density changes, a part of the X-ray beam is reflected. The interference of these partially reflected X-ray beams creates the oscillation pattern observed in reflectivity experiments. From these reflectivity curves, layer parameters such as thickness and density, interface and surface roughness can be determined through modeling.
In-plane diffraction: In-plane diffraction is a diffraction technique in which both the incident and diffracted beams are nearly parallel to the sample surface. Because the beam is incident at a grazing angle, the penetration depth of the beam is limited to within about 100 nm of the surface. The in-plane diffraction technique measures diffracted beams nearly parallel to the sample surface and hence measures lattice planes that are (nearly) perpendicular to the sample surface. These planes are inaccessible by other techniques.
Samples up to 4 inches in diameter may be analyzed.
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