X-ray Fluorescence or XRF is used for various applications in the scientific fields of geochemistry and archaeology. XRF is used in archaeological situations for determining the elemental or chemical composition of various artifacts. The analysis is based on the excitation of the inner electrons of the atom of the material under study. The sample is irradiated with X-ray beams. Put simply, the light that is given off will be reflective of the atoms within the material. This technique is employed for the purpose of identifying inorganic compounds such as glass, ceramics, pigments and metal alloys. For instance, scientists can take a ceramic fragment that may have pigment (for example a painted design) on the surface and through the use of XRF they are able to map the presence of each type of atom present, such as zinc, iron or titanium. This reveals the composition of the pigment used to create the design found on the sample under investigation. In turn, this can tell us about the types of material used. This is especially informative when the compositions of various possible sources are known and can be used for comparative purposes. In some cases, this technique can even reveal trace evidence of tools that may have been used for constructing the artifact.
Written by Michelle Machicek, PhD (Postdoctoral Researcher), Cornell University, Department of Anthropology and Smithsonian Institution, National Museum of Natural History for Time Team America (2013).