X-rays are electromagnetic waves in a particular wavelength range in the electromagnetic spectrum, and their properties are usually described by energy (in the KeV) and wavelength (unit: NM).
X-ray fluorescence is a phenomenon caused by changes in atoms. A stable atomic structure consists of a nucleus and a nuclear outer electron. The electrons in the nucleus operate on their own fixed orbits, and the inner electrons (such as the K-layer) are separated from the atoms under sufficient energy X-rays, releasing electrons that cause the electron shell to appear in the corresponding electron vacancy. Electrons in the high-energy electron shell, such as the L-layer, leap to the lower-energy electron shell to fill the corresponding electron vacancy. Because of the energy gap between the different electronic shells, the difference in energy is released in the form of two X-rays, and the two X-rays released by different elements have specific energy characteristics. This process is what we call X-ray fluorescence (XRF).
The atoms of the elements are stimulated by high-energy radiation to jump the inner electrons and emit x-rays with a certain wavelength, according to the Mosles law, the wavelength λ of the fluorescence X-ray is related to the atomic number Z of the element, and its mathematical relation is as follows:
Λ=k (z−s) −2
K and S are constants in the formula.