X-ray Fluorescence: Difference between revisions
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== Overview == | == Overview == | ||
X-ray fluorescence spectroscopy | X-ray fluorescence spectroscopy (XRF), also known as X-ray emission spectroscopy (XES), is a non-destructive characterization technique which gives elemental composition information. The MILL’s Niton FXL XRF accepts powdered, liquid, and bulk samples, and can detect elements heavier than magnesium (<math>Z\geq12</math>). It is best suited for ceramic and metallic samples. | ||
== Operation == | == Operation == | ||
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== Theory == | == Theory == | ||
In an atom, electrons are bound to the nucleus with discrete binding energies—this is due to the quantized energy states we understand as “orbitals” or “shells.” When a material is struck by source radiation of sufficient energy, it dislodges a core electron, resulting in a vacancy. This vacancy now must be filled, or quenched, by a higher-energy electron. When quenched, the energy difference between the two electron levels is considered a surplus, and must be re-emitted either as a photon or electron of that specific energy difference. This specific energy difference is characteristic to each element, and the resulting signal is therefore indicative of a material’s elemental composition. | |||
=== Fluorescence vs. Auger Behavior=== | |||
The two behaviors during re-emission are competitive and are the basis behind two different characterization techniques. If the surplus energy is re-emitted as a photon, it is called a secondary photon—this is also known as fluorescence. If re-emitted as an electron, it is called an Auger '''''(oh-ZHAY)''''' electron. When using an X-ray as the source radiation, the two techniques are subsequently called X-ray fluorescence spectroscopy (XRF) and Auger electron spectroscopy (AES). XRF is synonymous with X-ray emission spectroscopy (XES), since the detector is measuring the count and intensity of secondary X-rays. Typically, fluorescence is favored in heavier elements, and Auger behavior is favored in lighter elements—this is part of the reason why our XRF (and all XRFs) struggle to detect lighter elements. | |||
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Revision as of 16:53, 10 July 2021
| Niton XRF |
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| Elemental Range: Mg and up (Z 12) |
| Sample Type: Bulk, powders, & solutions |
Overview
X-ray fluorescence spectroscopy (XRF), also known as X-ray emission spectroscopy (XES), is a non-destructive characterization technique which gives elemental composition information. The MILL’s Niton FXL XRF accepts powdered, liquid, and bulk samples, and can detect elements heavier than magnesium (). It is best suited for ceramic and metallic samples.
Operation
Anyone who wishes to use or be trained on the XRD must undergo the general lab safety training AND the Georgia Tech Office of Radiological Safety (ORS) X-Ray Safety Training before reporting to the XRD Technical Officer.
Theory
In an atom, electrons are bound to the nucleus with discrete binding energies—this is due to the quantized energy states we understand as “orbitals” or “shells.” When a material is struck by source radiation of sufficient energy, it dislodges a core electron, resulting in a vacancy. This vacancy now must be filled, or quenched, by a higher-energy electron. When quenched, the energy difference between the two electron levels is considered a surplus, and must be re-emitted either as a photon or electron of that specific energy difference. This specific energy difference is characteristic to each element, and the resulting signal is therefore indicative of a material’s elemental composition.
Fluorescence vs. Auger Behavior
The two behaviors during re-emission are competitive and are the basis behind two different characterization techniques. If the surplus energy is re-emitted as a photon, it is called a secondary photon—this is also known as fluorescence. If re-emitted as an electron, it is called an Auger (oh-ZHAY) electron. When using an X-ray as the source radiation, the two techniques are subsequently called X-ray fluorescence spectroscopy (XRF) and Auger electron spectroscopy (AES). XRF is synonymous with X-ray emission spectroscopy (XES), since the detector is measuring the count and intensity of secondary X-rays. Typically, fluorescence is favored in heavier elements, and Auger behavior is favored in lighter elements—this is part of the reason why our XRF (and all XRFs) struggle to detect lighter elements.