Principle of the TXRF technique

Mo-W alloy anode) or a rotating anode tube. The beam is shaped like a strip of paper by means of precisely aligned slits its vertical divergence is adjusted to less than 0.01°. 

The fluorescence radiation is usually recorded with a Si(Li) detector and is registered by a multi-channel analyser as is the norm in energy-dispersive spectrometry. The detector is mounted directly above the sample, perpendicular to the sample support, at a distance of less than 1 mm in order to enlarge the angle of reception and to maximise the fluorescence intensity. Si(Li) detectors with active areas of 30 and SOnun and spectral resolutions of about 135 and 150 e V at 5.9 keV, respectively, are in common use. Normally measurements are performed in ambient air. 

TXRF spectrometers equipped with a combination of a Mo-W alloy anode and a double multilayer monochromator to date show the best compromise with respect to detection limits and multielement capability and are state of the art (TXRF 8030 C, Multielement Tracea-nalyzer Atomika Instruments, OberschleiBheim, Germany). 

TXRF spectrum of a clean quartz glass carrier. 

TXRF is characterised by multi-element determination, matrix independent calibration and single-element internal standardization, and low detection limits. In addition, the technique requires very low sample masses. Another significant feature of TXRF is its inherent surface sensitivity which makes it useful for surface analysis, a topic not discussed in this book. 

---