X-ray fluorescence

X-ray fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. When a sample is irradiated with X-rays, it absorbs some of the energy, causing the inner-shell electrons of the atoms in the sample to be ejected. As a result, electrons from higher energy levels within the atom fill these vacancies, and energy is released in the form of characteristic X-rays.