Laboratory-based Bulk EDXRF systems detect elements on the periodic table between atomic numbers 11 (sodium) and 92 (uranium). Samples can be analyzed non-destructively with little or no sample preparation in minutes and in some cases seconds. This capability is further enhanced by the technique's wide dynamic range.

Microbeam EDXRF systems use x-ray beam collimation (either mechanical or optical) to capture and transmit a substantially higher quantity of x-rays (100 to 1000 times that of traditional EDXRF) for for small spot analysis.

Portable EDXRF systems detect elements between atomic numbers 16 (Sulfur) to 92 (Uranium). These portable analyzers are usually dedicated to specific applications, such as metal verification, soil composition and mining ore analysis. They are field portable and hand held.

For lab-based systems, elements in concentrations from as low as a few parts per million to 100% may be analyzed in the same sample simultaneously. Accuracy of less than one percent relative error are attainable with comparable reproducibility. Portable instruments provide an accuracy of approximately 5% relative error and most detection levels are in the tenths of a percent with typical measurement times of 5 to 30 seconds.

How Does it Work?

Analysis by EDXRF involves use of ionizing radiation to excite the sample. This excitation ejects electrons from the atomic shells of the elements in the sample. When a given atom replaces the ejected electron, by taking another electron from an outer atomic shell, X-ray energies are emitted.

Since each element generates a specific energy level in this replacement process, these energies are known as characteristic X-rays. For example, if an electron in the K shell of a manganese atom is ejected, an energy of 5.894 kilo-electron volts (keV) is generated when an electron from that atom's L shell is moved to the K shell.

EDXRF spectrometers use a semiconductor material (an X-ray detector) to convert characteristic X-rays into electrical signals. The spectrometer's electronics digitize the signals produced by the detector, and send this information to a PC or internal electronics for display and analysis.

In measuring the energy level of the characteristic X-rays, we can determine what elements are present in the sample (qualitative analysis); and in counting and comparing the number of energies at the same energy level reaching the detector, we can determine percentages of the elements in the sample (quantitative analysis).

Microbeam XRF

Microbeam XRF uses collimating optics to focus the primary X-beam into an intensly focused spot as small as 20 microns. As features on critical materials become smaller and smaller, and metallic films on semiconductor and microelectronic devices become thinner, microbeam XRF provides a highly effective method to determine the composition of micron-sized materials and thin films.