5.2.1 Micro-XRF

In micro-XRF spectrometers the excitation originating from a micro-focus x-ray tube is collected with a poli-capillary lens and focused onto the sample surface.

When the sample (or the excitation-detection assemble) are moved in X and Y directions of the sample surface plane, maps can be collected depicting the distribution of the elements in the near surface layer. Gradient colour scales are customarily used to represent the differences in the measured characteristic energies intensities (elemental concentrations).

It is worth to notice that the measured signal bears information not only from the upmost surface layer contents, but from the effectively detected thickness, which depends on the sample matrix and the characteristic energy measured for each element (see example provided at the end of 5.1.1). The typical resolution at the surface is usually in the order of about 20 – 40 μm.