How does an xrf instrument work

Solid samples were the first sample types analyzed by X-rays. Over the years the applications expanded and nowadays the applications cover the analysis of alloys, various types of powder samples to liquid samples and filter material. The principle of XRF The effect of X-ray fluorescence is based on the excitation of atoms in the sample.

A primary X-ray, typically generated in an X-ray tube, hits an inner shell electron of the atom and ejects the election from the atom. The open position is filled by an electron from a further outer shell and fluorescence radiation is emitted. The fluorescence energy is equal to the energy difference between the two election shells.

Therefore, the energy of this radiation is characteristic for the atom and indicates, what atom is present in the sample. As many atoms are present in the sample, it will emit various X-rays with different energy. In an energy-dispersive XRF instrument the fluorescence radiation is collected by a semi-conductor detector. The X-rays create signals in the detector, which are depending on the energy of the incoming radiation. The signals are collected in a multi-channel-analyzer.

This process handles each X-ray one by one but with a high speed. A detector of a modern XRF machine can handle 1 million counts per second. These modules provide tutorials and examples covering a range of applications of geologic interest using the EarthChem Geochemical Database.

Geological Survey site shows how chemists and geologists use analytical chemistry to: determine the age of the Earth; show an extraterrestrial body collided with the Earth; predict volcanic eruptions; observe atmospheric change over millions of years; and document damage by acid rain and pollution of the Earth's surface.

Calculation of CIPW Norm from a Bulk Chemical Analsyis -- excel spreadsheet program, used to calculate norm from a bulk chemical analysis, with explanation of "norm" and calculation process. Material on this page is offered under a Creative Commons license unless otherwise noted below. Show terms of use for text on this page ».

Show terms of use for media on this page ». Your Account. Show Caption. An XRF spectrometer, with the sample port on top, and a set of samples in silver metallic holders in the sample changer in front. Reuse Citing and Terms of Use Material on this page is offered under a Creative Commons license unless otherwise noted below. Show terms of use for text on this page » Page Text A standard license applies as described above.

Click More Information below. Images image details Provenance No information about the origin of this particular item is recorded. Please contact SERC serc carleton. Reuse No information about limits on reusing this item have been recorded. Electrons are fixed at specific energies in their positions in an atom, and this determines their orbits. Additionally, the spacing between the orbital shells of an atom is unique to the atoms of each element, so an atom of potassium K has different spacing between its electron shells than an atom of gold Au , or silver Ag , etc.

Contact Us. When electrons are knocked out of their orbit, they leave behind vacancies, making the atom unstable. The atom must immediately correct the instability by filling the vacancies that the displaced electrons left behind.

Those vacancies can be filled from higher orbits that move down to a lower orbit where a vacancy exits. For example, if an electron is displaced from the innermost shell of the atom the one closest to the nucleus , an electron from the next shell up can move down to fill the vacancy.

This is fluorescence. Electrons have higher binding energies the further they are from the nucleus of the atom. Therefore, an electron loses some energy when it drops from a higher electron shell to an electron shell closer to the nucleus. They are produced specifically for analysis in an XRF spectrometer by grinding a sample to a fine powder using a laboratory crusher or pulverizer and mixing it with a binding agent, prior to compressing the mixture into a denser sample.

This provides exceptional analysis quality; however, pellets retain mineralogical structures which interfere with or alter the fluorescent process, impacting results accuracy. The preparation of samples as fused beads or discs reduces this issue, providing a near-perfect representation of the homogenous XRF reaction.

This process involves crushing the sample, then mixing it with a fusion flux of varying ratios into a platinum crucible. An XRF spectrometer can accurately examine a fusion bead or disc sample due to the reduction of its mineralogical matrixes. XRF Scientific is a global manufacturer and supplier of laboratory equipment and fusion flux mixtures for varied sample preparation methodologies.

We provide a catalog of products which can optimize sample preparation for analysis by an XRF spectrometer, improving results accuracy and laboratory throughput. If you would like any more information about preparing samples for XRF analysis, or supporting XRF spectrometer applications with additional equipment, please do not hesitate to contact us.

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