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e2v scientific instruments x-ray products |
Distributed products (UK only) |
Site last updated 06 Jun 2008
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Total Reflection X-ray Fluorescence (TXRF) is a very sensitive analysis technique for looking at low level concentrations of atomic elements. Common applications are the non-destructive quantification of surface contamination on Si wafers and polution studies using low ppm aerosols. |
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| The sample is excited by x-rays which are applied at a grazing incidence angle to a highly uniform, flat surface (substrate) on which the sample is either intrinsically present (eg. contaminant on Si wafer) or deposited. The principle is that the excitation beam is totally reflected by the substrate and only particles on the surface are excited giving rise to x-ray fluorescence emissions. In this way the background normally associated with XRF measurements is much reduced, leading to higher sensitivity and lower detection limits. |
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Because the quantity of material giving rise to fluorescence x-rays is very small, detection efficiency must be as high as possible. The detector is usually mounted as close to the sample as possible and a large area detector (typically 80mm² Si(Li) detector) is used to maximise the solid angle. e2v scientific instruments TXRF detectors are specially designed to operate with wide entry angle x-rays and the detector is constructed in such a way that background secondary fluorescence from the detector materials is extremely low. |
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