X-ray Fluorescence Spectrometers

X-ray fluorescence spectrometers (XRFs) use a spectroscopic technique that is commonly used with solids, in which X-rays are used to excite a sample and generate secondary X-rays.  The X-rays broadcast into the sample by X-ray fluorescence spectrometers eject inner-shell electrons. Outer-shell electrons take the place of the ejected electrons and emit photons in the process. The wavelength of the photons depends on the energy difference between the outer-shell and inner-shell electron orbitals. The amount of X-ray fluorescence is very sample dependent and quantitative analysis requires calibration with standards that are similar to the sample matrix.

The solid samples used with X-ray fluorescence spectrometers are usually powdered and pressed into a wafer or fused in a borate glass. The sample is then placed in the sample chamber of the XRF spectrometer, and irradiated with a primary X-ray beam. The X-ray fluorescence is measured either in simultaneous or sequential modes, and is recorded with either an X-ray detector after wavelength dispersion or with an energy-dispersive detector.

X-ray fluorescence spectrometers measure the emitted X-ray fluorescence in either a simultaneous fashion, or sequential.  Simultaneous mode typically measures the entire wavelength range around the emission line of interest simultaneously, while sequential mode typically measures one wavelength at time.

Wavelength dispersive detectors use a nondestructive analysis technique for the identification and quantification of elements in a material. Wavelength dispersive spectroscopy is the measurement x-ray energies emitted from the bombardment of an energy source impinged upon the material, producing characteristic x-rays.  Energy dispersive X-ray fluorescence spectrometers also use nondestructive analysis techniques for the identification and quantification of elements in a material. Energy dispersive spectroscopy is the measurement x-ray energies emitted from the bombardment of an energy source impinged upon the material, producing characteristic x-rays.

XRF was originally used to analyze geological samples. The advancement of computers and other technologies allowed the technique to develop even further.  XRF found its place in many different types of analytical laboratories and some industrial inspection systems. X-ray fluorescence spectrometers provide a number of distinct advantages including easy sample preparation, nondestructive rapid multi-element analysis, and the ability to screen unknowns in a wide array of sample matrices such as liquids, solids, slurries, powders, pastes, thin films, air filters, and many others.  Because of these advantages the technique, it is widely used for research, in industrial settings, and by quality assurance analysts.

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