EDXRF vs WDXRF
Definition
Energy-dispersive XRF reads all photon energies in parallel with a Si(Li) or silicon-drift detector; fast, cheap, lower resolution. Wavelength-dispersive XRF uses a crystal monochromator to select one wavelength at a time; higher resolution, better trace sensitivity, slower throughput.
- EDXRF detector
- Si(Li) or silicon-drift, parallel reading
- WDXRF detector
- Crystal monochromator, sequential reading
- EDXRF strength
- Speed, low cost
- WDXRF strength
- Resolution, trace sensitivity
Common questions
Why does WDXRF achieve better resolution despite being slower?+
A crystal monochromator physically diffracts and isolates one wavelength at a time before it reaches the detector, which separates closely spaced characteristic lines far better than a solid-state detector reading the whole spectrum in parallel, at the cost of scanning one element at a time.
When would a lab run both EDXRF and WDXRF on the same evidence?+
EDXRF is often used first as a fast qualitative screen to identify which elements are present, and WDXRF is then applied when quantitative precision or resolving trace elements with overlapping lines is needed for a more defensible result.
Related terms
- Bragg's Law
- nλ = 2d sin(θ). A monochromatic X-ray beam diffracted off the parallel lattice planes of a crystal produces constructive interference only at...
- Characteristic X-Ray
- An X-ray photon emitted when an outer-shell electron drops into an inner-shell vacancy created by ionisation. Energy is set by the difference...
- GSR Pb-Sb-Ba Signature
- The classical elemental signature of inorganic gunshot residue: lead from the bullet core, antimony from the priming compound, barium from the priming...
- ICDD PDF-4
- The Powder Diffraction File maintained by the International Centre for Diffraction Data. A reference database of more than 400,000 crystalline phases that...
- Moseley's Law
- The square root of the characteristic X-ray frequency varies linearly with atomic number Z. Discovered by Henry Moseley in 1913, it is...