X-Ray Fluorescence 

XRFX-Ray Fluorescence – is an analysis technique used in Positive Material Identification (PMI) equipment. X-rays are fired from the XRF equipment at the component requiring analysis.
The incident X-rays knock low-energy electrons out of their orbit around the atoms, as shown in (a) in the Figure. This leaves the atom unstable so the removed low-energy electron is replaced by a higher energy electron and the excess energy is given out as X-rays, as shown in (b).  The emitted X-rays are detected by a detector in the XRF equipment. The equipment is arranged so that the X-rays transmitted by the XRF equipment are incident on the component but do not affect the detector.

Each chemical element emits an X-ray with a unique energy value. So, by measuring the energies of the X-rays received at the detector, the specific elements generating the X-rays can be identified. The composition of the elements in the component can be calculated by measuring the number of X-ray signals received at each particular energy level. Once the element composition of the component is identified, it is a simple computer look-up task to identify the alloy grade.

For more information on XRF see:

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