Quantification of the monochromatic photon flux of refractive x‐ray monochromators in the energy range from 10 to 30 keV

Abstract

AbstractThe refractive properties of matter at incidence angles close to total reflection are used for monochromatization of continuous x‐radiation. Possible radiation sources are standard diffraction tubes with different target materials and either regular line focus or with fine focus. Theoretical considerations include Snell's law, dispersion theory and Fresnel's equations. The results of Monte Carlo calculations are as follows. The photon flux of the band‐shaped monochromatic beam with thicknesses of 20–40 µm, divergence of 0.01° and width of 10 mm depends on the x‐ray source, the refractor material, the angular combination of incidence and take‐off angle and, thus, on the pass energy of the monochromator. Numerical values of 104 photons s−1 were obtained with a tube with Mo anode, fine focus, 45 kV and 40 mA. Pass energies of 5–30 keV and widths of the pass energy range of 0.2–3.5 keV were obtained. The refractor materials were Si and n‐C33H68. The hydrocarbon refractor is characterized by a comparably much smaller photoelectric absorption and, consequently, better efficiency. Copyright © 2002 John Wiley & Sons, Ltd.