What is x ray fluorescence

Metallizing How to Control Corrosion by Improving Design. An Intro to Pipeline Corrosion in Seawater. Follow Connect with us. Sign up. Thank you for subscribing to our newsletter! Connect with us. Corrosionpedia Explains X-Ray Fluorescence XRF As a powerful tool for qualitative and quantitative elemental analysis tool, XRF can be used for archaeological, environmental, biological, industrial and geological analysis.

It works on wavelength-dispersive spectroscopic principles that are similar to an electron microprobe EPMA. However, an XRF cannot generally make analyses at the small spot sizes typical of EPMA work microns , so it is typically used for bulk analyses of larger fractions of geological materials. The relative ease and low cost of sample preparation, and the stability and ease of use of x-ray spectrometers make this one of the most widely used methods for analysis of major and trace elements in rocks, minerals, and sediment.

The XRF method depends on fundamental principles that are common to several other instrumental methods involving interactions between electron beams and x-rays with samples, including: X-ray spectroscopy e. The analysis of major and trace elements in geological materials by x-ray fluorescence is made possible by the behavior of atoms when they interact with radiation. When materials are excited with high-energy, short wavelength radiation e. If the energy of the radiation is sufficient to dislodge a tightly-held inner electron, the atom becomes unstable and an outer electron replaces the missing inner electron.

When this happens, energy is released due to the decreased binding energy of the inner electron orbital compared with an outer one. The emitted radiation is of lower energy than the primary incident X-rays and is termed fluorescent radiation. Because the energy of the emitted photon is characteristic of a transition between specific electron orbitals in a particular element, the resulting fluorescent X-rays can be used to detect the abundances of elements that are present in the sample.

The analysis of major and trace elements in geological materials by XRF is made possible by the behavior of atoms when they interact with X-radiation. An XRF spectrometer works because if a sample is illuminated by an intense X-ray beam, known as the incident beam, some of the energy is scattered, but some is also absorbed within the sample in a manner that depends on its chemistry. The incident X-ray beam is typically produced from a Rh target, although W, Mo, Cr and others can also be used, depending on the application.

Show Caption Hide An XRF spectrometer, with the sample port on top, and a set of samples in silver metallic holders in the sample changer in front.

When this primary X-ray beam illuminates the sample, it is said to be excited. The target metal elements and their regulation values are shown in Table 3. Halogen compounds have been used widely in electronic materials and other products as fire retardant materials.

However, because they generate harmful gas when burned dioxin in particular can be produced at high temperature and for environmental concerns such as preventing the destruction of the ozone layer, there is now a strong need to switch to halogen-free materials.

However, there is no clear definition of "halogen-free". It defines the total amount of chlorine Cl and bromine Br contained in epoxy resin and phenolic resin used in printed wiring boards.

Table 4. What is X-Ray Fluorescence? Figure 2 Fluorescent X-ray spectrum Sample. Relevant technical knowledge What are X-rays? Basic Knowledge. Return to listing. Next Article How to Use the Ampli…. Technical Knowledge in Listing The latest article How diodes work and what they are used for! X-ray fluorescence can detect and measure most elements in the periodic table running from Uranium, the heaviest element, all the way to lighter elements such as magnesium and beryllium.

As a versatile method of analysis, XRF is widely used for different sectors and disciplines. Here are some examples:. There are safety and quality control issues which XRF can help to address, as well as key areas of product development and testing.

As a common x-ray technique, XRF can measure a wide range of elements, such as the percentage of metals within inorganic materials. There are, however, limitations to XRF as an analytical method which could, in certain circumstances, be disadvantages:.

X-rays are part of the electromagnetic spectrum, with wavelengths between 0. The measurement of energy from the electron that is displaced, then replaced, is different depending on each specific element. XRF continues to develop, broadening the information this method can obtain from sample materials. Portable XRF technology especially is developing and improving, with handheld HRF spectrometers enabling the testing and chemical analysis of many varied materials in different conditions and locations.

HRF equipment is usually consists of either benchtop lab instruments or handheld spectrometer devices. Reading higher percentages can take only seconds, while calculating parts per million ppm may take several minutes. In spectroscopy, there are two fundamental components that an XRF analyser will have to function effectively and efficiently:. XRF analysers typically include an x-ray source, a detector, a digital signal processor and a central processing unit.

The operator should only hold it by its handle, and only use if for analysing materials that are positioned on a surface. That is because when the beam is emitted, a small amount of the x-rays will be scattered back towards the instrument. However, modern handheld analyser designs offer the highest level of protection against back-scattered x-ray radiation. The Rigaku Nex-CG , for example, can perform routine analysis, but also screen samples with totally unknown makeup, such as oil slurries.

Benchtop XRF analysers are closed-source x-ray spectrometers, which means they operate with full x-ray shielding that guarantees safe operation. Different models of analyser are ideal for different purposes, across a variety of industries and sectors.

There are also some fundamental safety aspects, which you must consider, when operating an XRF analyser:. Check our seminars and training section for details. XRF analysers can determine the chemical makeup of a sample by measuring the fluorescent, or secondary, x-ray the sample emits in response to an x-ray beam directed onto it.

Each element that is present in a sample will emit a characteristic set of fluorescent x-rays, unique to it. The most important part of XRF analysis is being able to look critically at the data collected and displayed in a spectrum. However to interpret this data properly, and easily, first requires that the XRF instrument has been properly calibrated.

Calibration will confirm that any measurements are accurate by measuring them against a pre-set standard. Unlike other some forms of spectroscopy, XRF does not require regular re-calibration between operations, but it is advisable to re-calibrate instruments periodically to ensure accurate readings.

XRF analysers have pre-programmed calibrations and settings to achieve these different measurements. However, although modern XRF analysers can function at a point-and-shoot level, it is important to understand the differences between these forms of analysis, to then interpret the data properly and practically.

Deciding what results you are looking for will be easier if you first understand what they measure and how they are different from each other. In XRF quantitative data contains a number and a unit, which is usually ppm parts per million or the percentage weight of the element present in the sample. Some calibrations are more heavily mathematics-reliant, while others are reliant on prior analysis of known samples.