The Working Principle of an XRF Spectrometer

An X-ray fluorescence (XRF) spectrometer is an X-ray instrument that is employed for the routine chemical analysis carried out on sediments, rocks, minerals and fluids. It is a relatively non-destructive technique that works on wavelength-dispersive spectroscopic principles. XRF instrumentation is generally used for bulk analyses of larger areas of minerals and materials.

The Key Principles of XRF

The technique used by XRF spectrometers is possible because of the behavior of the atoms when they interact with radiation. If material is excited via high-energy, short-wavelength radiation it may become ionized. If the energy is high enough it will have the capacity to dislodge an inner electron that has been tightly held. After this, the atom becomes unstable causing an outer electron to take the place of the missing inner electron, releasing energy.

How does an XRF Spectrometer Work?

An XRF spectrometer consists of two primary components; the x-ray output and a detector that is sensitive enough to determine fluorescent x-rays from the incident light. The array then emits X-ray or gamma-ray beams into a sample, exciting the electrons within. The inner atoms get displaced and the atoms that replace these are brought down from orbit shells above. This then decreases the binding energy, with the release of energy being known as fluorescence.

The benefit of using XRF analyzers such as spectrometers is that they register this energy bloom in real-time. There are many techniques of sample preparation for analysis by an XRF spectrometer, including:

• Liquids;
• Solid sample preparation;
• Powders;
• Fused beads;
• Pellets.

Sample surfaces are analyzed by XRF spectrometers and require very little sample preparation. Solid samples are ideally finished using grinding methods prior to analysis.

For liquid and powder samples, a support film is applied to provide as little interaction with the incident beam of the XRF spectrometer as possible.

Pellets offer exceptional insight into the homogenous makeup of a sample. They are grinded into a fine powder by using a laboratory crusher or pulverizer and mixing it with a binding agent, then compressed into a denser sample specifically for use in an XRF spectrometer.

This leads to an excellent quality of analysis although pellets do keep their mineralogical structures which can impact the fluorescent process, leading to less overall accuracy.

Sample preparation from XRF Scientific

XRF stocks and supplies fusion flux mixtures and lab equipment for use with XRF spectrometers and XRF analysis. To find out more about how we can help with you application, get in touch with the team for details.