Large aperture point-focusing diffractor for x rays

Wittry, D. B.; Golijanin, D. M.
April 1988
Applied Physics Letters;4/25/1988, Vol. 52 Issue 17, p1381
Academic Journal
A doubly bent germanium single crystal with toroidally curved crystal planes was used to obtain three-dimensional focusing of monochromatic x rays from a microfocus source. The Johansson geometry in radial planes was obtained by cutting a cylindrically curved lamella, polishing, etching, and bending over a spherical mold of ∼50 mm radius at 740 °C. The bent crystal was aligned to obtain the Cu Kα (333) reflection in the spot which had a principal focus of ∼100 μm. Allowing for anode pitting and extraneous reflections, the observed x-ray intensity was ∼10 times lower than expected theoretically. The discrepancy was attributed to imperfect bending and crystal defects.


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