GB1329695A - Diffractometry - Google Patents

Abstract

1329695 X-ray diffractometer J C NUTTER 9 Sept 1970 [3 Oct 1969] 48824/69 Heading GIA [ Also in Division H5] An X-ray diffractometer is designed, for analysis of a continuously moving specimen, in such a way that a plurality of the beams diffracted by the specimen may be detected without movement of the detector. In the arrangement of Fig. 1, the beam from tube target S is a continuous spectrum and is collimated at R and applied to a powder or alloy specimen M moving in a stream into the plane of the drawing. Diffracted radiation is detected via slit B by detector D. In order to differentiate between the proportions of the diffracted beam due to different constituents in the specimen, the detector circuit includes an array of pulse height analysers P after the linear amplifier C. By varying the analyser selected, the rate of pulses of the same amplitude in different amplitude bands may be measured, each band corresponding to a particular wavelength and thus lattice spacing, which in turn is characteristic of a particular constituent. If the chart recorder Q is synchronised with the analyser variation, a diffraction pattern will be traced out. Instead of single pulse height analysers, a multi channel device may be used to give a more complete pattern trace. In the arrangement of Fig. 2, Seemann-Bohlin focusing is used to avoid the need for a very small specimen. The specimen is curved with the detector D located at a point on the circle of sample curvature. Similar circuitry to Fig. 1 is used. Slit B may be dispensed with. The detector may be, for example, a silicon surface barrier device, or a lithium drifted silicon or germanium device. Fluorescent radiation may be prevented from interfering with the measurements by use of suitable filters