| 摘要 |
1,183,514. Fluorescence analysis. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. March 21, 1968 [April 28, 1967], No.19833/67. Heading G1A. In the analysis of a mixture containing a wanted element, an interfering element and a base rock, the mixture is subjected to ionizing radiation, e.g. X-rays, and separate measurements are carried out to determine the intensities I w , I i of the fluorescent radiation at the characteristic fluorescent energies of the wanted element and of the interfering element, respectively, and the intensity, I b , of the backscattered radiation over an energy band intermediate between, but not containing, the characteristic fluorescent energies of the wanted and interfering elements. A calibration nomogram, e.g. as in Fig.5 (not shown), is prepared using known samples by plotting I i /I b against I w /I b , and using this the quantity of the wanted element and of the interfering element in an unknown specimen may be determined. The three measurements representing the two intensities of fluorescence and the backscattered intensity are obtained by the use of four filters and a conventional backscatter geometry analysis arrangement, utilizing a scintillation or proportional counter. For example, in the determination of copper in gypsum (hydrated calcium sulphate) or artinite (magnesium carbonate), the interfering element in which is iron, a pair of balanced filters of chromium and manganese are used to determine the iron K-line intensity, and a further pair of cobalt and nickel, to determine the copper. The backscattered intensity derived from the base rock is measured in an intermediate band not including either the iron or copper K-line by using the manganese and cobalt filters in combination. If more than one interfering element is present, further filters are necessary and a threedimensional nomogram is required to be plotted. |
