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Synchrotron
About: Synchrotron is a research topic. Over the lifetime, 7646 publications have been published within this topic receiving 112537 citations.
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TL;DR: In this paper, the application of the Rietveld refinement technique to synchrotron X-ray data collected from a capillary sample of Al2O3 in Debye-Scherrer geometry is described.
Abstract: The application of the Rietveld refinement technique to synchrotron X-ray data collected from a capillary sample of Al2O3 in Debye–Scherrer geometry is described. The data were obtained at the Cornell High Energy Synchrotron Source (CHESS) with an Si(111) double-crystal monochromator and a Ge(111) crystal analyzer. Fits to a number of well resolved individual peaks demonstrate that the peak shapes are very well described by the pseudo-Voigt function, which is a simple approximation to the convolution of Gaussian and Lorentzian functions. The variation of the Gaussian and Lorentzian half widths, ΓG and ΓL, with Bragg angle can be approximated quite closely by the functions V tan θ and X/cos θ which represent the contributions from instrumental resolution and particle-size broadening respectively. Rietveld refinement based on this model yields generally satisfactory results. The refined values of V and X are consistent with the expected vertical divergence (≃0.1 mrad) and the nominal particle size (≃ 0.3μm). In particular, the use of a capillary specimen virtually eliminates preferred orientation effects, which are highly significant in flat-plate samples of this material.
2,469 citations
Book•
01 Jan 1983
TL;DR: In this paper, an overview of the application of synchrotron radiation for angiography is presented, with a focus on the use of the Bragg reflection monochromator.
Abstract: Preface. 1. Synchrotron X-ray scattering studies of Langmuir films (J. Als-Nielsen and H. Mowald). 2. Coronary angiography project at the Photon Factory using a large monochromatic beam (K. Hyodo, K. Nishimura and M. Ando). 3. Optical and dielectric properties of materials relevant to biological research (M.W. Williams, E.T. Arakawa and T. Inagaki). 4. Crystal-structure analysis of biological macromolecules by synchrotron-radiation diffraction (H.D. Bartunik). 5. Fibre diffraction: collagen (A. Bigi and N. Roveri). 6. Scattering from non-crystalline systems (M.H.J. Koch). 7. Synchrotron radiation sources (W. Brefeld and P. Gurtler). 8. A Bragg reflection monochromator for synchrotron radiation angiography (G.S. Brown). 9. Trace element analysis by X-ray fluorescence (A. Iida and Y. Gohshi). 10. Medical applications of synchrotron radiation (J.C. Giacomini and H.J. Gordon). 11. Microradiography and microtomography (W. Graeff and K. Engelke). 12. NIKOS - non-invasive angiography at HASYLAB (W. Graeff and W.-R. Dix). 13. Radiobiological experiments in the X-ray region with synchrotron radiation (K. Hieda and T. Ito). 14. Synchrotron radiation for angiography, an overview (E. Rubenstein and R. Hofstadter). 15. X-ray microscopy (G. Schmahl and P.-C. Cheng). 16. UV spectroscopy (E.S. Stevens). 17. Anomalous X-ray scattering (H.B. Stuhrmann, G. Goerigk and B. Munk). 18. Detectors for angiography (A. Thompson). 19. Progress in X-ray synchrotron diffraction studies of muscle contraction (K. Wakabayashi and Y. Amemiya). 20A. Imaging apparatus and techniques for synchrotron radiation (H.D. Zeman). 20B. The processing of intravenous coronary angiograms produced by synchrotron radiation (H.D. Zeman). Author index. Subject index.
1,277 citations
TL;DR: The problem of determining the three-dimensional structure of thousands of atoms is reduced to that of initially solving for a few anomalous scattering centers that can be used as a reference for developing the entire structure.
Abstract: Resonance between beams of x-ray waves and electronic transitions from bound atomic orbitals leads to a phenomenon known as anomalous scattering. This effect can be exploited in x-ray crystallographic studies on biological macromolecules by making diffraction measurements at selected wavelengths associated with a particular resonant transition. In this manner the problem of determining the three-dimensional structure of thousands of atoms is reduced to that of initially solving for a few anomalous scattering centers that can then be used as a reference for developing the entire structure. This method of multiwavelength anomalous diffraction has now been applied in a number of structure determinations. Optimal experiments require appropriate synchrotron instrumentation, careful experimental design, and sophisticated analytical procedures. There are rich opportunities for future applications.
1,113 citations
TL;DR: In this paper, it was shown that if n alternates rapidly between large positive and large negative values, the stability of both radial and vertical oscillations can be greatly increased compared to conventional accelerators in which n is azimuthally constant and must lie between 0 and 1.
1,034 citations
TL;DR: The new technique of x-ray microtomography nondestructively generates three-dimensional maps of the x-rays attenuation coefficient inside small samples with approximately 1 percent accuracy and with resolution approaching 1 micrometer.
Abstract: The new technique of x-ray microtomography nondestructively generates three-dimensional maps of the x-ray attenuation coefficient inside small samples with approximately 1 percent accuracy and with resolution approaching 1 micrometer. Spatially resolved elemental maps can be produced with synchrotron x-ray sources by scanning samples at energies just above and below characteristic atomic absorption edges. The system consists of a high-resolution imaging x-ray detector and high-speed algorithms for tomographic image reconstruction. The design and operation of the microtomography device are described, and tomographic images that illustrate its performance with both synchrotron and laboratory x-ray sources are presented.
722 citations