| 摘要 |
Apparatus and method to indicate the concentration of a selected element within a target wherein separated polychromatic X-rays produce first and second monochromatic X-ray beams, the wavelength of the first beam being slightly less than the absorption edge of the selected element and the wavelength of the second beam being slightly greater than the absorption edge of the selected element. The first and second beams irradiate the target to produce fluorescent characteristic radiation of the target elements which is received by a first and second detecting means for producing a first and second digital signal, respectively. A monitoring means produces a third digital signal indicative of intensity fluctuations of the polychromatic x-rays. A differential ratio computer means produces an output signal which is the difference between the first and second digital signals divided by the third digital signal, which output signal indicates the concentration of the selected element within the target. First, second and third movable wedges are utilized in calibrating the device and to provide an indication of the concentration of the selected element in percent deviation from a standard or in engineering units (mg/dm2).
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