X-ray fluorescence

Measure almost any element in almost any matrix

X-ray fluorescence (XRF) provides one of the simplest, most accurate and most economic analytical methods for the determination of elemental composition of many types of materials. Indispensable to both R&D and quality assurance (QA) functions, our advanced and unique WDXRF products are routinely used to analyze products from cement to plastics and from metals to food to semiconductor wafers. Rigaku offerings range from high power, high-performance wavelength dispersive WDXRF systems, for the most demanding applications, to a complete line of benchtop EDXRF and WDXRF systems.

Theory of X-ray fluorescence

XRF SchematicIn X-ray fluorescence (XRF), an electron can be ejected from its atomic orbital by the absorption of a light wave (photon) of sufficient energy. The energy of the photon (hν) must be greater than the energy with which the electron is bound to the nucleus of the atom. When an inner orbital electron is ejected from an atom (middle image), an electron from a higher energy level orbital will be transferred to the lower energy level orbital. During this transition a photon maybe emitted from the atom (bottom image). This fluorescent light is called the characteristic X-ray of the element. The energy of the emitted photon will be equal to the difference in energies between the two orbitals occupied by the electron making the transition. Because the energy difference between two specific orbital shells, in a given element, is always the same (i.e. characteristic of a particular element), the photon emitted when an electron moves between these two levels, will always have the same energy. Therefore, by determining the energy (wavelength) of the X-ray light (photon) emitted by a particular element, it is possible to determine the identity of that element.

For a particular energy (wavelength) of fluorescent light emitted by an element, the number of photons per unit time (generally referred to as peak intensity or count rate) is related to the amount of that analyte in the sample. The counting rates for all detectable elements within a sample are usually calculated by counting, for a set amount of time, the number of photons that are detected for the various analytes' characteristic X-ray energy lines. It is important to note that these fluorescent lines are actually observed as peaks with a semi-Gaussian distribution because of the imperfect resolution of modern detector technology. Therefore, by determining the energy of the X-ray peaks in a sample's spectrum, and by calculating the count rate of the various elemental peaks, it is possible to qualitatively establish the elemental composition of the samples and to quantitatively measure the concentration of these elements.


Benchtop tube below sequential WDXRF spectrometer analyzes F through U in solids, liquids and powders
Low-cost EDXRF elemental analyzer measures Na to U in solids, liquids, powders and thin-films
    ZSX Primus / SSLS
High power, tube below, sequential WDXRF spectrometer with Smart Sample Loading System (SSLS)
  Primini Biofuel
Benchtop WDXRF optimized for sub-ppm detection limits for P, S and Cl in petroleum products
    NEX CG
High-performance, Cartesian-geometry EDXRF elemental analyzer measures Na to U in solids, liquids, powders and thin-films
    ZSX Primus II
High power, tube above, sequential WDXRF spectrometer with mapping and superior light element performance
  Mini-Z Sulfur
ASTM D2622 method WDXRF analyzer for sulfur (S) in petroleum fuels and ULSD
  NEX QC+ QuantEZ
NEX QC+ with powerful Windows® software and optional FP.
    Simultix 14
High throughput tube below multi-channel simultaneous WDXRF spectrometer analyzes Be through U
  Mini-Z Series
Tube below, single element WDXRF analyzer for quality control applications
    NEX DE 
New 60 kV EDXRF system featuring QuantEZ software and optional standardless analysis.
    ZSX Primus III+
High power, tube above, sequential WDXRF spectrometer
  Micro-Z ULS
Dedicated ultra-low sulfur analyzer for petroleum
    AZX 400
Large sample capability; high power, tube below, sequential WDXRF spectrometer with mapping