The use of toroidal reflecting surfaces in x-ray diffraction cameras

An x-ray collimating system suitable for observing diffraction patterns of fibres, powders and films with radiation of 1.54 Å wavelength is described. The system uses a gold-coated toroidal mirror and enables diffraction patterns to be recorded photographically in much less time than is required with conventional systems giving equal resolution. A substantial degree of monochromatization is obtained, and with the current system spacings shorter than about 35 Å may be observed. A camera in which the film is in the form of a cone is also described. Typical exposure times with a Hilger and Watts generator giving 3 mA at 45 kv are 5 minutes for rolled aluminium foil and 30 minutes for a crystalline polymer such as nylon 6, with a specimen-film distance of 3 cm.