Meaning
Multi-energy x-ray beams lose intensity at different rates as they pass through materials of varying density and atomic number. When analyzing composite structures, polychromatic attenuation causes the lower-energy photons to be absorbed first, progressively hardening the x-ray spectrum as it penetrates deeper. This phenomenon affects the accuracy of computed tomography scans used to inspect industrial components for internal voids.
Energy Spectrum
Industrial scanners emit a wide range of wavelengths rather than a single energy level. As the beam travels through the object, the changing profile caused by polychromatic attenuation produces discrepancies between the measured density and the actual material composition. This error shows up as streak artifacts or cupping effects on the final cross-sectional images.
Artifact Mitigation
Computational algorithms reconstruct the raw data to compensate for beam hardening. This correction ensures that dense inclusions in metal castings are not obscured by visual streaks.
Material Characterisation
High-performance inspection labs utilize dual-energy scans to separate the effects of density and atomic composition. By measuring the transmission of two distinct energy peaks, the software models the effects of polychromatic attenuation and provides a precise map of the internal geometry. This technique is essential for validating the thickness of ceramic coatings on turbine blades where millimeter-scale precision is required.
