Journal of X-Ray Science and Technology - Volume 2, issue 3

Authors: Karabekov, I. P. | Egikian, D. L.

Article Type: Research Article

Abstract: The development and experimental study of a method for determining the degree of surface and volume perfection of crystals by measuring the widening of the collimating slit image in synchrotron radiation beams diffracted by an (n, +n) spectrometer are presented.

DOI: 10.3233/XST-1990-2301

Citation: Journal of X-Ray Science and Technology, vol. 2, no. 3, pp. 161-164, 1990

Authors: Partanen, J. | Tuomi, T.

Article Type: Research Article

Abstract: X-ray section topographs of nearly perfect Czochralski-grown wafers were made with synchrotron radiation having a continuous spectrum. An intensity curve measured from the x-ray film is compared to the calculated curve obtained using the dynamical theory of x-ray diffraction. A computer simulation of the topograph is also presented. A good agreement between theory and experiment is found except in the middle part of the topograph.

DOI: 10.3233/XST-1990-2302

Citation: Journal of X-Ray Science and Technology, vol. 2, no. 3, pp. 165-171, 1990

Authors: Stead, A. D. | Ford, T. W. | Catcheside, J. A. | Hills, C. P. | Ridgeley, A.

Article Type: Research Article

Abstract: The optimum wavelengths for soft x-ray contact microscopy of biological specimens are between 2.2 and 4.4 nm as, relative to water, this gives maximum contrast between carbon- and oxygen-containing constituents. Irradiation outside of this so-called “water window” interferes with either the resolution and/or the contrast that can be obtained. The previous belief that silicon nitride windows act as an effective filter for the longer wavelength, XUV radiation generated from laser-produced plasmas is shown to be suspect. However, in this study the use of aluminum-coated windows, which effectively exclude these longer wavelengths, still permits successful imaging of biological specimens. The added …strength imparted to coated windows also ensures their survival during the imaging process, thereby demonstrating that the tissues can remain hydrated at the time that the image is formed in the photosensitive resist material used in this technique. Show more

DOI: 10.3233/XST-1990-2303

Citation: Journal of X-Ray Science and Technology, vol. 2, no. 3, pp. 172-179, 1990

Authors: Davis, Timothy J.

Article Type: Research Article

Abstract: A set of transformation equations is derived to map DuMond diagrams between crystal faces in a multi-crystal system. The equations are constructed from the Bragg equation linearized about some angle and include the effects of refraction and asymmetry of the crystal faces. The equations form the basis of a ray tracing program for x rays to aid in the design of monochromators.

DOI: 10.3233/XST-1990-2304

Citation: Journal of X-Ray Science and Technology, vol. 2, no. 3, pp. 180-194, 1990

Authors: Yao, G.-D. | Dudley, M. | Wu, J.

Article Type: Research Article

Abstract: The technique of synchrotron white beam topographic imaging in grazing Bragg-Laue geometries has been developed at the Stony Brook synchrotron topography station (beamline X-19C) at the National Synchrotron Light Source. This technique enables both general quality characterization and imaging of defects in subsurface regions of thickness which can range from hundreds of angstroms to hundreds of micrometers as determined by the effective penetration depth of the x rays. This penetration depth, which is shown in most cases to be determined by the kinematical theory of x-ray diffraction, can be conveniently varied in a controlled manner by simple manipulation of the …diffraction geometry, thereby enabling a depth profiling of the defect content. The fundamentals of the technique are described, and its advantages and disadvantages compared to existing techniques are discussed. Brief examples of the application of the technique in the characterization of defects in both single crystals and heteroepitaxial systems are given, and the general applicability of the technique is discussed. Show more

DOI: 10.3233/XST-1990-2305

Citation: Journal of X-Ray Science and Technology, vol. 2, no. 3, pp. 195-213, 1990

Authors: Zegenhagen, J. | Materlik, G. | Uelhofff, W.

Article Type: Research Article

Abstract: Experimental requirements for measuring the structure and coverage of adsorbates in the monolayer regime on single crystals with x-ray standing wavefields are discussed in detail along with a thorough description of the theory. The near-surface region of Cu crystals was probed depth selectively by detecting K as well as L fluorescence as a function of fluorescence escape angle. The effects of crystalline imperfections and of dispersive crystal arrangements on the spatial resolution of standing wave measurements are described. Copper crystals with (111) and (100) surface orientation were used as substrates for electrodeposition of Cd and Tl from an aqueous electrolyte …using cyclic voltammetry. Submonolayer amounts of Cd and Tl deposited in the underpotential range were investigated on the emerged electrodes with x-ray standing waves keeping the samples under atmospheric pressure, in air, or in inert atmosphere. Show more

DOI: 10.3233/XST-1990-2306

Citation: Journal of X-Ray Science and Technology, vol. 2, no. 3, pp. 214-239, 1990