Fluorescence spectra, photoelectric measurement

Figure 2.4, a photoelectric absorption can be followed by the emission of a characteristic X-ray of the absorbing medium. There is a significant possibility that this fluorescent X-ray may escape the shielding and that it will be detected by the detector, as indicated in Figure 2.13. The result will be a number of X-ray peaks in the gamma spectrum in the region 70-85 keV. This may or may not be a problem in practice, depending upon the type of gamma-ray spectrum measured. However, if low-energy gamma-ray measurements are contemplated, fluorescent X-rays are an unnecessary complication.

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