Point focusing x-ray camera and the study of total external reflection

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.