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Published byMillicent Goodwin Modified over 9 years ago
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O RBIS — Micro-EDXRF System
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XRF Advantages Non-destructive: No beam damage or coating of sample Minimal Sample Preparation: conductivity not required sample shape can be irregular Detection limits improve: 10x or better (vs. SEM-EDS) Navigation by Optical Microscope Low Vacuum (~ 300 mTorr) or No Vacuum (Air) More appropriate than SEM for larger scale features X-rays are penetrating (microns to millimeters)
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Sample Chamber / XYZ Stage Chamber Door Width ~ 500 mm Height ~ 515 mm Can be set up to swing: Right to left (as shown) Left to Right Open access to sample chamber
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Manual Control and Analysis
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Spectral Mapping: Mapping Examples
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Elemental Spatial Distribution Maps: Paper Mg MapAl MapFe Map Generation of BMP Elemental Maps Fe X-rays penetrate paper
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Mapping Metal Analysis: Coins (Non-Destructive) * Rare Coin (2 Reichsmark - 1927?) * Pixels: 64 x 50 Map * Dwell time: 0.3 s/pixel * Total time ~ 20 minutes Conclusion: Counterfeit Coin Conclusion: Counterfeit Coin
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Cl Mapping of Cement Core: Filtered Excitation Surface Treatment Cross Section Cement Core Goal: To access diffusion of Cl into cement from deicing agent where Cl could corrode supporting steel Cores are cross-sectioned Rough cut (often there is a desire to avoid polishing to minimize sample preparation or corruption of the sample) Acquisition of data with Rh-tube, poly-capillary optic and Al(thin) filter to remove interfering scatter from Rh(L) tube line
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Cement Chemistry – Road Salt: Filtered Excitation Data courtesy of J.M. Davis, Microanalysis Research Group – NIST Map images processed and displayed using Lispix SW Surface Treatment
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Spectral Mapping - Bone Fossilization Fe Na K Si P Data courtesy of George Havrilla, LANL
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Map Tool: Substitution Map Image Overlay Fe – Red K – Blue Si – Yellow P – Gray Na - Green Bone Fossilization
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Map Tool: Elemental Image Overlay – RGB Phase Analysis Bone fossilization Ca – Red Bone Si – Green mineral P – Blue Bone Substitution Overlay Image: Ca-Si-P
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Map Tool: Elemental Image Overlay – RGB Phase Analysis Bone fossilization Bone – purple (Ca, P) New mineral – orange (Ca, Si)
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Spatial Distribution Maps: Facial Tissue Tissue masked with carbon tape for Si-free zone Mapping region 15.6 mm x 11.3 mm
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Map Tool: Data Mining Recall spectra from mapped pixels Hot Si spots hide low-level Silicone coverage
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Map Tool: 3-Log Band Image Scaling 3 individual color logarithmic scales (NIST) Low level Silicone distribution exposed in Green
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Spectral Mapping with Poly-capillary and Filter – Alumina supported Catalysts Ag supported on Alumina SpheresPd supported on Alumina pellets Objective: Measure metal distribution in ceramic support Samples: Embedded in epoxy and cross-sectioned on one side (no polish) Ag(L), Pd(L) versus Ag(K), Pd(K) L-lines probe ~ 20 m into ceramic; no need to make a thin section K-lines probe ~ 4 mm into ceramic; interference from opposite surface Map Acquisition: Rh tube excitation requires filter to remove Rh(L) interference Poly-capillary: ~ 55 mm FWHM lateral resolution at Ag(L), Pd(L) Thin Al filter to remove Rh(L) from exciting spectrum True Analytical flexibility in micro-XRF beam
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Spectral Mapping – Alumina supported Catalysts Ag(L) Map: Thermal Image ScalingPd(L) Map: Thermal Image Scaling Objective: Measure metal distribution in ceramic support Samples: Embedded in epoxy and cross-sectioned on one side (no polish) Metal is concentrated in the exterior shell of the ceramic support
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Spectral Mapping – Alumina supported Catalysts Ag(L) Map: 3 Log Band Image ScalingPd(L) Map: 3 Log Band Image Scaling Objective: Measure metal distribution in ceramic support Samples: Embedded in epoxy and cross-sectioned on one side (no polish) Specialized Image Scaling reveals important distributional details Ag(L) map shows interior ring of Ag at weaker concentration, but no internal Ag Pd(L) map shows the interior pellet has weak, uniform concentration of Pd
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High Resolution Spectral Mapping – Odessa Meteorite (20mm x 16 mm) Area ~ 20 mm x 16 mm RGB Merge Fe – Red Ni – Green P - Blue Elemental Image OverlayTotal Spectral Count Image (TSC Image) Fe – green Ni – blue Cr – cyan S – magenta Cl – yellow P - red
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High Resolution Spectral Mapping – Odessa Meteorite (20mm x 16 mm) Elemental Image Overlay P Cl Fe S Ni Fe
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High Resolution Spectral Mapping – Odessa Meteorite (20mm x 16 mm) RGB Merge Fe – Red Ni – Green P - Blue Fe:Ni (Kamacite) Fe:Ni (Taenite) Fe:Ni:P( * ) (Schreibersite) * * * * * * * * * *
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High Resolution Spectral Mapping – Odessa Meteorite (20mm x 16 mm) RGB Merge Fe – Red Ni – Green S - Blue Fe:Ni (Kamacite) Fe:Ni (Taenite) FeS (Troilite)
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