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Characterization of Nanoparticles from Spark Ablation
Published in Andreas Schmidt-Ott, Spark Ablation, 2019
It is fairly common to analyze spark-ablated particles using powder XRD with a lab source, but the spectra very often have low signal-to-noise ratios. An important consideration when preparing specimens for such measurements is to deposit the particles onto a substrate that interferes with the signal of the particles as little as possible, since the substrate will often dominate the measurements. To get a useful signal one needs to deposit enough material on the substrate; how much depends on the quality of the X-ray lab source and the detector used, and the particles to be analyzed. For small crystallites (nanoparticles), the small size will contribute to a broadening of the Bragg peaks, according to the Scherrer equation. This enables estimation of the particle size. Basically, this broadening also means that the smaller the particles are, the lower the signal-to-noise ratio will be. XRD has, for example, been used to demonstrate that the addition of hydrogen to the carrier gas results in the production of spark-ablated Bi particles instead of BiO particles that are produced when no hydrogen is added [15]. XRD has also been combined with small-and wide-angle X-ray scattering (SWAXS) in the analysis of magnetic spark-ablated nanoparticles [21]. Small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) are variations of XRD techniques where the X-rays scattered to small and wide angles, respectively, are analyzed.
Physical Structure
Published in Rudolf Puffr, Vladimír Kubánek, Lactam-Based Polyamides, 2019
Josef Baldrian, František Lednický
Wide angle X-ray scattering (WAXS) is used as one method for crystallinity determination because each phase produces a different type of X-ray diffraction pattern. It can also be obtained from density and calorimetric measurements under the assumption that the crystalline and amorphous regions are two separate thermodynamic phases with corresponding ideal densities and enthalpy contents, respectively.
Microstructural Characterization of Conjugated Organic Semiconductors by X-Ray Scattering
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
Maged Abdelsamie, Michael F. Toney
Wide angle X-ray scattering (WAXS) measurements typically use experimental configurations to cover wide scattering angles, such as the detector area, the X-ray wavelength, and sample-to-detector distance which is usually relatively small. WAXS can be applied in a variety of configurations including transmission or reflection geometries such as powder X-ray diffraction (XRD) and grazing incidence X-ray scattering (GIXS) [37, 38]. Transmission WAXS requires the samples to have sufficient transparency to X-ray beam to allow transmitted and scattered X-ray beam to be collected at the detector. For OSCs, which are often thin films, scattering through transmission is limited by the weak order in OSCs and the small probed material volume. Alternatively, this transmission geometry can be applied to bulk samples or solutions to allow sufficient material volume for scattering [39, 40]. Similarly, powder diffraction geometry is limited for bulk samples such as extruded polymers due to the weak order of organic materials [41].
Angle calibration and error analysis of wide-angle X-ray scattering (WAXS) with a one-dimensional linear detector
Published in Instrumentation Science & Technology, 2021
Rongchao Chen, Zhihong Li, Ying Shi, Li-Zhi Liu, Yuexiang Wang, Baoliang Lv
Wide angle X-ray scattering (WAXS) or diffraction (WAXD or XRD) based on either synchrotron radiation or common lab based light source is a technique in which X-rays are elastically scattered by a sample in the angstrom-range at wide angles (typically 2θ > 5°). The technique provides information about the structure of matter at the molecular and atomic scales.[1–3]