A high-resolution X-ray diffractometer for the study of imperfect materials

Abstract

A high‐resolution X‐ray diffractometer devoted to the study of imperfect materials (mainly oxides and ceramics) is presented. It is based on a rotating anode generator, a four‐bounce monochromator, a five‐movement sample holder and a curved position‐sensitive detector (PSD). This setup allows rapid acquisition of a reciprocal‐space map (in less than 10 h) even for very poorly diffracting materials. The two‐dimensional instrumental profile is calculated taking into account each optical element in the beam path. The one‐dimensional instrumental profiles corresponding to widely used scans (ω scan, θ–2θ scan, rocking curve and powder scan) are also calculated. In the three former cases, the setup exhibits an excellent angular resolution (0.003°), whereas in the latter case the resolution is lowered by one order of magnitude at the benefit of a strong increase in the collected intensity. The possibilities of this diffractometer are illustrated with three examples: an epitaxic layer, a microstructured single crystal and a powder.

X-ray diffuse scattering from stacking faults in thick 3C-SiC single crystals

“…5 HRXRD experiments were conducted on a laboratory equipment mounted on a high power x-ray source and equipped with a curved position sensitive detector ͑PSD͒. 12 Maps of the diffracted intensity close to the ͑002͒ Bragg peak of ͑001͒ SiC and close to the ͑111͒ Bragg peak of ͑111͒ SiC were recorded for different azimuthal positions of the sample ͑Fig. 1͒.…”

Characterization of stacking faults in thick 3C-SiC crystals using high-resolution diffuse X-ray scattering

“…the distance between two points in the crystal; q is the deviation of the scattering vector from the Bragg position (q ¼ QÀh); R(r) is the Fourier transform of the resolution function of the diffractometer. This term can be exactly evaluated [9] and will not be detailed here. V(r) is correlation volume [11] which describes the effects of the shape and size of the coherently diffracting domains (mosaic domains), as well as their size fluctuations.…”

“…The X-ray beam impinging on the sample is monochromatic (Cu Ka 1 , Dl/l ¼ 1.4 Â 10 À4 ) and parallel in the detector plane (Dy ¼ 12 arcsec) with dimensions 10 Â 0.09 mm 2 so that a large volume of the sample is analyzed which provides statistically significant averaged values. A detailed description of the setup has been given elsewhere [8][9][10]. An RSM represents the scattered intensity in a particular (Q x , Q z ) plane, where Q x and Q z are the components of the scattering vector Q (Q=4p sin y/ l) in the crystal plane and perpendicular to it, respectively.…”

Advanced techniques for characterization of ion beam modified materials

“…The recording of reciprocal space maps (RSMs) provides a two-dimensional distribution of the scattered intensity in the vicinity of a Bragg reflection. The use of position sensitive detectors, instead of a slit-or analyzer-based detection system, dramatically reduces the counting times [53].…”