Long wave-length x-ray diffraction crystal and method of manufacturing same

An x-ray diffraction crystal of the Langemuir-Blodgett type capable of detecting radiation having a wavelength greater than 50 Arystroms and a method of making such a crystal are described. The crystal consists of a pair of alternate monolayers, one a heavy metal soap, and one a light metal soap. Selecting cation pairs with a significant difference in atomic number and dispersing power, such as Pb and Be, Mg, or Ca, increases the effective interplanar distance since the Pb planes cause the predominant x-ray diffraction. (LL)