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Crystal Monochromator (crystal + monochromator)
Selected AbstractsUsing the general equation of a conic for the calculation of the instrument function of a Bragg,Brentano diffractometerJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2008A. D. Zuev The general equation of the conic representing the intersection of the receiving-slit plane with the diffraction cone as well as with the reflection cone of a plane crystal monochromator are given for a diffractometer in Bragg,Brentano geometry. Apart from the fact that this equation can be easily used to calculate the total instrument function as well as specific instrument functions for diffractometers in Bragg,Brentano geometry, it also provides tools for elucidating different aberrations of the diffractometer in Bragg,Brentano geometry. [source] A novel lattice-spacing comparator with resolution of 10,8JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2003Xiaowei Zhang A novel, fast and stable system for measuring the lattice spacing of a silicon crystal with a precision of 10,8 is described. Self selection of monochromatic X-rays by a monolithic double channel-cut crystal monochromator (MDCM), producing silicon 264 and 624 diffraction, may lead to a stable, highly collimated and narrow-bandwidth beam. When utilizing the 264 and 624 Bragg reflections of a silicon sample, the angular distance between the two associated Bragg peaks must be extremely small, so that the diffraction angle can be determined with high precision and the traveling time from one peak to the other can be considerably reduced by the order of at least three compared with the established classical Bond method. This so-called self-reference comparator method can dramatically save measurement time and can provide an absolute measurement on the basis of the known X-ray wavelength available from the MDCM. Thus a lattice-spacing measurement with resolution of 10,8, within a few tens of seconds for an area of 1,mm2 on a silicon sample, has been realised. [source] A dedicated small-angle X-ray scattering beamline with a superconducting wiggler source at the NSRRCJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2009Din-Goa Liu At the National Synchrotron Radiation Research Center (NSRRC), which operates a 1.5,GeV storage ring, a dedicated small-angle X-ray scattering (SAXS) beamline has been installed with an in-achromat superconducting wiggler insertion device of peak magnetic field 3.1,T. The vertical beam divergence from the X-ray source is reduced significantly by a collimating mirror. Subsequently the beam is selectively monochromated by a double Si(111) crystal monochromator with high energy resolution (,E/E, 2 × 10,4) in the energy range 5,23,keV, or by a double Mo/B4C multilayer monochromator for 10,30 times higher flux (,1011,photons,s,1) in the 6,15,keV range. These two monochromators are incorporated into one rotating cradle for fast exchange. The monochromated beam is focused by a toroidal mirror with 1:1 focusing for a small beam divergence and a beam size of ,0.9,mm × 0.3 mm (horizontal × vertical) at the focus point located 26.5,m from the radiation source. A plane mirror installed after the toroidal mirror is selectively used to deflect the beam downwards for grazing-incidence SAXS (GISAXS) from liquid surfaces. Two online beam-position monitors separated by 8,m provide an efficient feedback control for an overall beam-position stability in the 10,µm range. The beam features measured, including the flux density, energy resolution, size and divergence, are consistent with those calculated using the ray-tracing program SHADOW. With the deflectable beam of relatively high energy resolution and high flux, the new beamline meets the requirements for a wide range of SAXS applications, including anomalous SAXS for multiphase nanoparticles (e.g. semiconductor core-shell quantum dots) and GISAXS from liquid surfaces. [source] A comment on `A new ray-tracing program RIGTRACE for X-ray optical systems' [J.JOURNAL OF SYNCHROTRON RADIATION, Issue 2 20031050], Synchrotron Rad. (2001) Some points concerning the characteristics of the X-ray simulation code SHADOW [Welnak et al. (1994). Nucl. Instrum. Methods, A347, 344,347] are clarified which are not correctly mentioned by Yamada et al. [J. Synchrotron Rad. (2001), 8, 10471050]]. It is shown that, contrary to the authors' statement, some functionality of their new program is not original. In particular, we show that SHADOW can deal correctly with crystal monochromators. [source] | ||||||||||