Focusing mirror system

Focusing mirror system Two bent metal mirrors that deflect the X-ray beam and produce a small intense beam with a narrow angular divergence, uniform beam profile and a low background intensity. They are useful for experiments involving crystals with large unit cells. 

The sample was placed in a quartz cell in a thermostated holder (25 + 0.5 °C). The laser line was focused by a lens and mirror system and the scattored light... 

A mirror system for directing or focusing light energy... 

For DRIFT studies, a wood wafer, paper sheet, or milled wood sample dispersed in KBr (or KC1) is placed in a cup at the focal point of the concave, ellipsoidal mirror so that the incident light is focused on the sample. The scattered light coming from the sample is collected from the concave mirror and directed by a suitable mirror system to the detector of the FTIR instrument. The pressure used for smoothing the sample has to be adjusted so that reproducible results can be obtained (Yeboah et al. 1984). The contribution of specular reflectance can be diminished by reducing the particle size and by increasing the sample dilution. For powder samples, as indicated above, the diluent is KBr or KCI. Good results are normally obtained with alkali halide powders that contain 1-2% of sample. In certain cases, the sample concentration may be increased up to 10%. 

The total reflection of mirrors can be used to focus the radiation. Synchrotron radiation, while collimated in the vertical plane it spreads over the horizontal one. Wavelength resolution requirements normally restrict the vertical aperture to one mm or so, in any case. On the other hand it is desirable to condense the horizontal spread into a focal point. Double focussing with a mirror system is possible and an ideal mirror geometry has been worked out For a point source the mirror has to be shaped like an ellipsoid, and the source and the image have to be placed in the respective foci. The long distances involved in synchrotron work mean that a good approximation to shape is achieved by making use of bent cylindrical mirrors ... 

Often a system similar to that shown in Fig. 16.25—or with focusing mirrors—is used for shadowgraph studies. Note that when shadowgraphs are taken, the knife edge (in Fig. 16.25) would be removed and the screen would not be placed at the conjugate focus of the test section. 

Figure 4.6. Schematic arrangement of conventionai diffuse-reflectance accessory for measuring multiple-transmission spectra of microsamples. (1,2) focusing optical system of accessory (3) sample holder (4) plate under study (5) metallic mirrors, (a) Plate with polished surfaces placed between ground metallic surfaces. (6) Plate with ground surfaces placed between polished mirrors. Reprinted, by permission, from V. P. Tolstoy, Methodsof UV-Vis and IR Spectroscopy of Nanolayers, St. Petersburg University Press, 1998, p. 130, Fig. 4.10. Copyright 1998 St. Petersburg University Press.

Concentrating Collectors. Hybrid solar lighting systems use sun-tracking focusing mirrors and optical fiber transmission to provide interior lighting. Typically half of the incident sunlight can be transmitted to rooms, where it replaces or supplements conventional lighting. 

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