Development of Hamos-type X-ray micro-analyzer using a cylindrically, bent graphite monochromator

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Fluorescent radiations emitted from a certain point in a sample are focused by diffracting on the inner surface of a cylindrically bent single crystal. Using this fundamental principle, an X-ray microanalyzer has been developed. Three important study results contribute to the present development.(1) First of all, a new fabrication technique of a cylindrical bend graphite single crystal with a large curvature is essential in order to effectively collect fluorescent radiation from a sample. In the present study, the cylindrical graphite with a curvature radius of 2l.07mm was produced by the new fabrication process developed by Matsushita Electric Industrial Co. Ltd.(2) Secondarily, an XMA apparatus consisting of a sealed X-ray tube, sample holder, the bend graphite monochromator and an imaging p]ate as a two dimensional detector was designed so that the best suited performance is expected.(3) Thirdly, a computer program for image data processing based upon the maximum entropy principle was developed to improve a special resolution of the observed image.From the above results, the present XMA apparatus has been developed. In the present circumstances, the best spatial resolution that has been achieved in the present XMA is about 0.1 mm. This is about 10 times larger than the common XMA apparatus using electron convergent beams (EPMA) and about one tenth of the ordinary X-ray fluorescent analyzer. In addition, it takes a quite long time for the image data processing by the present program. We must improve its algorism for better performance. In spite of the worse spatial resolution, the pres t system can be applied to some materials which are not measured by EPMA, such as wet materials, melts, some biomaterials. Consequently, we will develop the present XMA as the complimentary method of EPMA as well as improve it for a better performance.