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For trace element determination in TXRF, monochromatic X‐rays coming from an X‐ray source, as mentioned above, are passed through a slit so that a parallel beam of X‐rays is obtained and unwanted scattered X‐rays are cutoff. This parallel monochromatic beam is made to fall on a sample support containing a thin specimen of the sample at an angle less than the critical angle, corresponding to the monochromatic beam and sample support being used for sample excitation[5,8,10]. The sample is excited efficiently, as mentioned above, and the emitted X‐rays are detected using a Si(Li) or any other solid state detector. The totally reflected beam is stopped by a beam stopper so that it does not pass further and harm any laboratory personnel in the area. A schematic of the TXRF configuration is shown in Figure 4.4 given below.