X-ray fluorescence (XRF) is the emission of characteristic “secondary” (or fluorescent) X rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays. Each element present in a sample emits its own unique fluorescent x-ray energy spectrum. By simultaneously measuring the fluorescent X-rays emitted by elements in the sample, XRF analyzers can determine the elements present in the sample and their relative amounts. X ray fluorescence is widely used for elemental analysis and chemical analysis, particularly in the investigation of metals, glass, ceramics and building materials, and for research in geochemistry, forensic science and archaeology.