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Showing papers on "Total external reflection published in 1982"


Journal ArticleDOI
TL;DR: In this article, a method is developed for calculating the scattering of a beam of x rays striking the plane surface of a crystal at an angle below the critical angle for total external reflection.
Abstract: A method is developed for calculating the scattering of a beam of x rays striking the plane surface of a crystal at an angle below the critical angle for total external reflection The low penetration under this condition offers the possibility of determining the special structure of the surface layers, as has been pointed out by Marra, Eisenberger, and Cho A distorted-wave approach is developed whereby the crystal is first taken to be a homogeneous dielectric slab for the purpose of calculating the distorted wave The distorted wave is considered to illuminate the actual crystal, from which a scattering pattern can then be calculated The effects of absorption can be taken into account; in some cases absorption may offer the possibility of observing near-surface structures at angles of incidence larger than the critical angle Such illumination may also be useful for performing fluorescence analysis of the near-surface layers to determine their impurity content Synchrotron sources offer new opportunities for measurements of these kinds Thermal neutrons may also be used in place of x rays and offer unique opportunities for studying surface magnetization and, through inelastic scattering, surface phonons and, conceivably, surface magnons

410 citations


Patent
27 Dec 1982
TL;DR: In this article, the phase, amplitude or both phase and amplitude of the reflected light can be modulated by thermally induced changes in the first index of refraction, and a method of modulating a first optical beam with a second optical beam is also provided.
Abstract: An optical imaging device includes an optical device comprising means for absorbing at least one wavelength of light incident thereupon, a first layer of a first material having a first index of refraction and being in thermal contact with the absorbing means, and a second layer of a second material having a second index of refraction which is larger than the first index of refraction and which forms an interface with the first layer. The first layer is placed between the absorbing means and the second layer. The phase, amplitude or both phase and amplitude of the reflected light can be modulated by thermally induced changes in the first index of refraction. A method of modulating a first optical beam with a second optical beam is also provided.

14 citations


Journal ArticleDOI
TL;DR: In this paper, a point focusing x-ray camera with two bent (horizontal and vertical) reflectors was designed and made, where the horizontal reflector uses a glass mirror and the vertical reflector either uses either glass mirror or a monochromator.
Abstract: The total external reflection coefficients of a glass and gold reflector for CuK radiation were determined experimentally, with results in good agreement with the theoretical calculation. Partial monochromatization of the reflected beam by the glass reflector was also verified experimentally. Based on this study, a point focusing x‐ray camera with two bent (horizontal and vertical) reflectors was designed and made. The horizontal reflector uses a glass mirror, and the vertical reflector uses either a glass mirror or a monochromator. This camera can thus be used in either a mirror–mirror (Franks optics) or a mirror–monochromator configuration (Huxley–Holmes optics). By changing the vertical reflector, the configuration can be simply exchanged and the best use of the characteristics of the two available optics can be made. The choice of optics depends mainly upon the irradiated size of the specimen: the mirror–mirror optics gives narrow beams (3′–6′), and the mirror–monochromator optics gives convergent beams (1°–1.2°) and much greater intensity. Small‐and wide‐angle diffraction patterns are detected with variations of specimen to film distance. For diffraction angles smaller than about 1°, both cases require a fine focus source smaller than about 0.1×0.1 mm in projection to prevent the production of Kα1–Kα2 doubled diffraction pattern by the monochromator and a reduction of resolution due to the extent of the focusing point by the glass reflector.

9 citations


Journal ArticleDOI
TL;DR: In this paper, the sound reflection coefficient is defined as an unknown function of the integral equation of the first kind, referring to the reflection of a surface element on a rigid plane.
Abstract: In an auditorium, an absorbent boundary is used in order to control the reverberant field. Its reflection composes a part of the early reflections and can not be neglected to estimate the transfer function. The sound reflection coefficient is defined as an unknown function of the integral equation of the first kind, referring to the reflection of a surface element on a rigid plane. It is very difficult with the equation to determine the coefficient which changes depending on incident and reflection angles. When a panel covered with a surface having a reflection coefficient which changes continuously and smoothly is large enough, the kernel function leaves the contribution around the specular reflection point and then the coefficient there can be separated experimentally. The reflection of a panel of limited dimension with such a reflection coefficient is approximately obtained by the convolution of the coefficient and the reflection of the rigid panel at the same position of the panel. Calculated and measured results are compared in the time and frequency domains. This method is also applied to a convex and a concave panel covered with a layer of such a reflection coefficient. The reflection of a panel with a mutual arrangement of strips of two different reflection coefficients is also discussed.

6 citations


Journal ArticleDOI
TL;DR: In this paper, a high-efficiency mirror material was selected and optimized optical geometry and filtering conditions were determined using curves of calculated and measured intensity versus glancing angle, a high efficiency mirror material were selected and a high efficient filter was determined.
Abstract: Since specular reflection of characteristic X-rays can become nearly total external reflection at grazing incidence, total reflection analysis offers an alternative to the wavelength dispersive method based on Bragg reflection. Using curves of calculated and measured intensity versus glancing angle, a high-efficiency mirror material was selected and the optimized optical geometry and filtering conditions were determined. Short wavelength X-rays could be eliminated and overlapping interference of equal and longer wavelength X-rays was excluded using the equation for determining the element concentration. Analytical examples for Al, C and B are described.

6 citations


Journal ArticleDOI
TL;DR: In this paper, a spherical wave incident at a grazing angle is reflected from a plane interface where the relative index of refraction is near unity, and strong interference between the lateral wave and the specular reflected wave takes place.
Abstract: When a spherical wave, incident at a grazing angle, is reflected from a plane interface where the relative index of refraction is near unity, it turns out that strong interference between the so-called lateral wave and the so-called specular reflected wave takes place. Numerical calculations to illustrate the effect are presented.

1 citations