Two modifications of the Kratky small-angle X-ray camera

A Kratky small-angle X-ray camera has been modified in two respects to provide increased sensitivity and performance. (1) Flexible metal bellows seals have been mounted between the collimation system vacuum cover and the specimen chamber and between the specimen chamber and the tank which provides a vacuum path to the detector. The consequent elimination of four Mylar windows in the X-ray path near the sample resulted in a significant reduction in the background scattering. The degree of improvement depends on several variables including the collimation system geometry, X-ray tube power, and the electronic noise of the counting system. (2) A flat piece of hot-pressed pyrolytic graphite has been mounted as a diffracted beam monochromator. Experimental results show the diffracting efficiency of the graphite to be about 25% - a value sufficiently high that for the same total counting time, the detector will record the same net number of X-ray photons as with balanced filters but with much improved statistics.