An x-ray milliprobe analyser with photographic recording of the spatial distribution of elements.
An X-ray milliprobe analyser has been built and its performance and usefulness evaluated. The instrument consists of a fluorescent X-ray spectrometer in which the primary X-ray beam from the sealed-off tube is collimated so that only a small area on the specimen, 0.3 or 1 mm in diameter, is irradiated. The large loss in intensity of the fluorescent X-rays is offset to some extent by the use of a focussing curved-crystal analyser. The usefulness of the instrument has been greatly increased by the incorporation of an automatic raster scanning motion in the sample holder, and of a similar motion in a colour-film holder which moves across a light beam. The colour of this beam is altered according to the measured concentration of the element, so that a coloured mosaic picture of its distribution is built up. The limits of detection of a wide range of elements are in the range 200-2000 ppm for the rather short counting period of 10 sec per point which is necessary when scanning a large area.
Campbell
J T
JT
Analytical Sciences Division, Atomic Energy Research Establishment Harwell, Berks., U.K.
Garton
F W
FW
Wilson
J D
JD