XRF Instrument

Axios Sequential X-ray Fluorescence Spectrometer.

Axios Sequential X-ray Fluorescence Spectrometer (XRF)

Location Room:1.25B | Member of Staff: Mr Paul Lythgoe or Mr Alastair Bewsher

                                                                                                                                                     

X-ray fluorescence (XRF) spectrometry is a non-destructive analytical technique used to identify and determine the concentrations of elements present in solid, powdered and liquid samples. The XRF spectrometer measures the individual component wavelengths of the fluorescent emission produced by a sample when irradiated with X-rays.

Wavelength separation (WDXRF) is achieved by diffraction, using an analyzer crystal. The specific lattice of the crystal selects the correct wavelengths according to Bragg's law.

A sequential spectrometer employs an optical assembly called a goniometer, which is equipped with two concentric, rotatable shafts. These enable the analyzing crystal to turn through angular increments (theta degrees), while the detector rotates through 2-theta degrees to intercept the diffracted beam. Spectral peaks are detected at various wavelengths, according to the conditions described by Bragg's Law.

The results of continuous scanning over an angular range can be plotted as a spectrum, from which the elements present in a sample may be identified. Individual peak intensities are measured to determine element concentrations.

Measurement times as short as 2 seconds suffice for many elements - although longer times are required for the lightest elements, which produce relatively small numbers of characteristic fluorescent photons.

Uses
Major and trace element analysis. Elements of atomic number 8 (O) to 95. Limit of detection depends on the element concerned and the concentrations of other elements that may interfere.

Routine programs are available:

Trace element analysis: Pro-Trace produces accurate and reliable trace element analysis on a broad range of sample types - with detection limits from sub-ppm to 6ppm dependant on element. Pro-Trace uses specially prepared blank specimens and calibration standards.

Typical run time 2 hours per sample. For powdered samples, sample weight 12g +3g wax binder.

Major element analysis with Omnian: Omnian is a software package based on an advanced fundamental parameters algorithm. It has the flexibility to handle a wide variety of materials with accurate results over wide ranges of concentration (0% to 100%).

Typical run time 17 minutes per sample. For powdered samples, sample weight 12g +3g wax binder.

 

A Furnace is available that can be controlled at temperatures between 110º and 1100º. It can be used to determine samples’ weight losses on ignition at a stated temperature. 
It is useful to be able to complete the analyses of samples which contain water; &/or carbonates; &/or organic substances.

Contains extracts from the PANalytical webpage.

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