ZAF Correction
Definition
A software correction applied to raw EDS X-ray intensities to account for atomic number (Z), absorption (A), and fluorescence (F) effects within the interaction volume, producing accurate elemental concentration values from the measured spectra.
- Corrects for
- Atomic number (Z), absorption (A), fluorescence (F)
- Applied to
- Raw EDS X-ray intensities
- Purpose
- Accurate elemental concentration from spectra
- Application context
- SEM-EDS quantitative analysis
Common questions
Why can't raw EDS intensity counts be used directly as elemental concentrations?+
Raw X-ray intensities are distorted by matrix effects: heavier elements backscatter electrons differently, some X-rays are absorbed before escaping the sample, and some elements fluoresce others within the interaction volume, so the ZAF correction models these effects to convert measured counts into accurate concentrations.
Which of the three ZAF effects typically has the largest impact on light elements?+
Absorption tends to dominate for light elements, since their lower-energy characteristic X-rays are more readily reabsorbed within the sample before reaching the detector, which is why quantifying light elements accurately generally requires more careful correction than heavier elements in the same spectrum.
Related terms
- ASTM E1588
- ASTM International standard practice for gunshot residue analysis by scanning electron microscopy with energy-dispersive spectrometry. Defines particle classification (characteristic, consistent-with, indicative), morphology...
- Back-Scattered Electron (BSE)
- High-energy electron from the primary beam that has bounced elastically off a nucleus and exited the sample. BSE yield increases with atomic...
- 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...
- Energy-Dispersive X-Ray Spectroscopy (EDS)
- An X-ray detection method that simultaneously measures the energies of all characteristic X-ray photons emitted from the interaction volume, identifying all elements...
- FIB (Focused Ion Beam)
- A technique using a focused gallium ion beam to mill a specimen at a specific site-selected location, producing a TEM-quality cross-section with...
- Interaction Volume
- The pear-shaped region of specimen material within which the primary electron beam deposits energy and generates signals. At 20 kV in a...
- Lead-Free GSR
- Gunshot residue produced by ammunition using non-lead primer formulations (SINTOX, Diazol, or other variants). Does not contain the conventional Pb-Sb-Ba three-element combination;...
- Secondary Electron (SE)
- Low-energy electron (below 50 eV) ejected from the top few nanometres of the sample when the primary beam knocks a loosely bound...
- Silicon Drift Detector (SDD)
- The current standard EDS detector type, using a reverse-biased silicon chip cooled by a Peltier element to achieve high count-rate capability (up...
- Sputter Coating
- Vacuum-deposition technique that lays a thin (5 to 15 nm) conductive layer of gold, gold-palladium or carbon onto a non-conductive sample (polymer,...
- Ultramicrotome
- A precision instrument for cutting sections of resin-embedded specimens to 60-100 nm thickness using a diamond knife, enabling TEM examination of the...