Here is how it works. An X-ray photon hits an atom and knocks out an electron from an inner shell. This leaves an empty spot close to the nucleus.
An electron from a higher shell then drops down to fill that spot. As it drops, it gives off energy as a new X-ray photon. Every element releases X-rays at its own set of energies, based on its atomic number.
A detector reads these energies and tells scientists which elements are present and roughly how much of each there is. XRF does not destroy or damage the sample in any way. This makes it a great tool for checking art, coins, and ancient artifacts.
It can also test many elements at the same time in one quick scan. XRF instruments come in two main types. Wavelength dispersive systems give very precise readings but scan slowly.
Energy dispersive systems, now common in small handheld scanners, read faster and let inspectors test items right in the field, such as at a mining site or a customs checkpoint. Recycling plants also use handheld XRF scanners to sort scrap metal quickly by alloy type.
Museums, mining companies, and factories all rely on XRF because it gives fast, reliable results without cutting or dissolving anything.