What Is X-Ray Fluorescence (XRF)?
XRF is a non-destructive analytical technique used to determine the elemental composition of materials. An XRF analyzer identifies a sample's chemical composition by measuring the fluorescent (or secondary) X-rays emitted by the sample when it is excited by a primary X-ray source. Each element in the sample produces a unique set of characteristic fluorescent X-rays, which is why XRF spectroscopy is an excellent technology for the qualitative and quantitative analysis of material composition.
The X-ray fluorescence process
All XRF instruments are built around two main components: an X-ray source (usually an X-ray tube) and a detector. The source generates primary X-rays and directs them at the sample surface, sometimes through a filter that modifies the X-ray beam. When the beam strikes atoms in the sample, they respond by producing secondary X-rays, which the detector collects and processes.
The X-rays emitted by atoms in the sample are collected by the detector and processed in the analyzer to produce a spectrum showing X-ray intensity peaks against their energy. The peak energy identifies the element, while the peak area (or intensity) indicates how much of it is in the sample.
The analyzer then uses this information to calculate the sample's elemental composition.
The entire process—from pressing the start button or trigger to receiving the analysis result—can take as little as 2 seconds or as long as several minutes.
It all depends on the instrument being used, the range of elements measured, and their concentrations.
The energy of an emitted X-ray is characteristic of its element. This means XRF provides qualitative information about the sample being measured. However, XRF is also a quantitative technique.
What happens to atoms in a sample during analysis?
A stable atom consists of a nucleus and electrons orbiting around it. Electrons are arranged in energy levels, or shells (K, L, M, N), and each level can hold a different number of electrons.
When a high-energy primary X-ray strikes an atom, it disturbs the atom's equilibrium. An electron is ejected from a low energy level, leaving a vacancy and making the atom unstable.
To regain stability, an electron from a higher energy level falls into the vacancy. The excess energy released as the electron moves between the two levels is emitted as a secondary X-ray.
How is XRF used across industries?
Handheld XRF analyzers identify alloys, detect tramp elements, provide geochemical data, analyze precious metals, and determine coating weight and plating thickness to ensure materials meet chemical specifications.
- Oil and gas — for positive material identification (PMI) of pipework, which is critical when flow-accelerated corrosion or sulfide corrosion is a concern
- Metal fabrication — for non-destructive elemental analysis to ensure the wrong or out-of-spec metal or alloy does not enter the manufacturing process
- Automotive & aerospace — for incoming inspection and quality control of metal parts and coatings
- Scrap metal recycling — for fast, accurate scrap sorting, essential to improving both workflow efficiency and profitability
- Precious metal recycling — to accurately identify precious metal grades and prevent harmful metals from entering the recycling process
- Mining & exploration — to quickly identify and recover the most economically viable resources
- Construction & environmental engineering — for risk assessment screening, hazardous-site modeling, and remediation quality control
Is XRF safe?
During analysis, the analyzer emits a directed radiation beam while the tube is energized. Reasonable efforts should be made to keep radiation exposure well below applicable dose limits. Three factors help minimize exposure: time, distance, and shielding.
Although radiation from a portable or handheld XRF analyzer is similar to exposure from a routine dental or medical X-ray, care must be taken to point the analyzer directly at the sample and never at a person or body part. Here are seven safety tips:
- Provide radiation safety training for operators
- Never point the instrument at yourself or anyone else when the main beam (X-ray on) indicator is illuminated
- Never hold a sample during analysis
- Pay attention to the main beam indicator
- Handle and use the instrument responsibly
- Store it safely and follow local storage requirements
- In a radiation safety emergency, notify your Radiation Safety Officer and analyzer supplier
Where can you buy professional X-ray equipment?
We specialize in supplying X-ray equipment, including X-MET8000 Series handheld material analyzers and the Hitachi High-Tech X-Strata920 benchtop coating-thickness analyzer.
Frequently Asked Questions
You can point an XRF analyzer at almost anything and get a result. Common applications include scrap metal sorting, alloy identification (PMI), quality control (QC) in metal manufacturing, geological exploration or mining, testing industrial materials such as cement or coal, and testing for lead in paint or other hazardous substances in consumer products.
The lightest elements in the periodic table (for example, magnesium, hydrogen, carbon, nitrogen, oxygen, and sodium) produce X-rays too weak to return to the detector, so they cannot be detected by XRF. XRF tells you how much of each detectable element is present in a material, but does not provide information about the material's chemical structure.
Yes. Handheld XRF is safe when operated as instructed. XRF instruments produce X-rays, a form of ionizing radiation, so you should always follow the ALARA principle (As Low As Reasonably Achievable). The basic rule—like anything shaped like a gun—is never point it at anyone and pull the trigger. Handheld XRF power is far lower than that of radiography, so users receive a dose close to natural background radiation.
We offer a range of XRF configurations to suit different applications and performance levels. Each has calibration parameters for different sample types and materials. Quốc Huy's specialists can help you choose the right instrument for your needs.
It is not complicated for the user. With the right instrument and calibration for the samples, simply point and shoot; the result appears clearly and completely on the screen. HHXRF instrument interfaces are designed like smartphones, so users will find them familiar.
