EDXRF and WDXRF Flashcards
1
Q
How does WDXRF work?
A
- Uses crystals to disperse fluorescence spectrum into individual wavelengths of each element.
- Provides high res and low background spectra for accurate determination of elemental concentrations
- Crystals include minerals, metals, organic and synthetic multilayers.
2
Q
What is Bragg’s Law?
A
WDXRF is based on Bragg’s Law, states that crystals will reflect x-rays of specific wavelengths and incident angles when the wavelengths interfere constructively.
Lambda is the wavelength, d is the lattice spacing and theta is the angle.
3
Q
What is EDXRF?
A
- Uses a SSD and multichannel analyser to collect fluorescence x-ray spectrum from sample
- SSD and multianalyser then plot intensity of the XRF against their energy.
4
Q
What are the strengths and weaknesses of each technique?
A
- EDXRF has higher resolutions than WDXRF which reduces spectral overlaps; complex samples can be more accurately characterised. Improves DL and sensitivities
- WDXRF has additional optical components meaning it suffers from reduced efficiency and higher costs.
- EDXRF acquires an entire spectrum simultaneously whereas WDXRF is made in point-by-point fashion or has a very limited number of simultaneous detectors (expensive)
