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Basics.
Micro X-ray fluorescence spectroscopy is a rapid and non-destructive technique used to acquire quantitative chemical data at high spatial resolution (i.e. µm-scale).
Whether small or large, smooth or uneven, the instrument is equipped with a large high-speed stage that supports 2D analysis of virtually any kind of inorganic and organic samples.
The Bruker M4 TORNADO is equipped with two silicon drift detectors that offer an excellent count rate capability combined with a stable energy resolution (<145 eV). The vacuum system enables the operating pressure to be decreased to 20 mbar in less than 120 seconds, enabling a better transmission for lighter elements.
Image 1: Micro-XRF Bruker M4 TORNADO.
Courtesy of Bruker.
Excitation of X-ray fluorescence radiation is induced by an X-ray tube with a polycapillary optic. The X-ray transmission efficiency through the capillary optic decreases for high energy elements. For the detection of the fluorescence, one or two energy dispersive detectors are used. These features enable the detection of elements from sodium to uranium and the detection of major, minor and trace elements.
X-ray Source
Focusing X-ray optic
Sample
Detector
Figure 2: Micro-XRF X-ray beam.
Courtesy of Bruker.
By scanning the surface with a focused X-ray beam, the elemental composition and spatial distribution of major, minor and some trace elements can be determined. Precise measurements can be made at a rate of millimetres per second. The instrument can perform these measurements “on-the-fly” with data collection simultaneous to the movement of the sample stage, reducing the total time needed for analysis completion.
These measurements can provide a qualitative overview of the elemental distribution in large samples, and can be acquired as either single-point, multi-point line scanning or area maps.