ORNL Neutron Imaging NXS 2022 - Yuxuan Zhang, Jean Bilheux, Jiao Lin, Hassina Bilheux
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ORNL Neutron Imaging NXS 2022 Yuxuan Zhang, Jean Bilheux, Jiao Lin, Hassina Bilheux July 10-22, 2022 ORNL is managed by UT-Battelle, LLC for the US Department of Energy
The Neutron Imaging Team Yuxuan Zhang, Jean Bilheux, Jiao Lin, S. Venkat Shimin Tang, Artificial HFIR CG-1D Computational STS CUPI2D Scientist Venkatakrishnan, Adv. Intelligence, Machine Scientist Instrument Scientist Reconstruction Learning, Hyperspectral /Machine Learning Imaging Erik Stringfellow, Mary-Ellen Donnelly, Harley Skorpenske, Jamie Molaison, Hassina Bilheux, Imaging SA Imaging SA SNS Group Leader SNS SNAP SA SNS VENUS Scientist 2
Imaging has a broad scientific portfolio Soft Matter and Materials for Materials Polymers, 3% infrastructure, 3% degradation, 3% Composites, 3% Materials science - Biomass and General, 17% Biofuels, 3% Porous media, 6% Nuclear Energy materials , materials, 6% 11% Medical applications, 6% Phase Industrial transformations/kin Life applications , 6% etics, 11% Fluids , 9% science , 9% Earth and environmental science, 6% 3
Imaging is a Growing Part of the ORNL Neutron Sciences Program High Flux Isotope Reactor (HFIR) Spallation Neutron Source (SNS) Intense steady-state neutron flux World’s most powerful accelerator-based neutron source and a high-brightness cold neutron source Techniques such as Bragg-edge imaging are being implemented on BL3 SNAP diffractometer (VENUS is under construction) Dedicated Imaging Instrument (CG-1D) Steadily improving capabilities Expanded support Future CUPI2D beamline at STS (Bragg edge and grating interferometry) 4
Bragg edge Scattering Grating Microscopy Radiography, Interferometry Computed Tomography and Resonance Radiograph of a membrane in a proton exchange membrane fuel cell (PEMFC) at a resolution of 1.98 μm Radial average absolute differential macroscopic cross section vs. wavevector transfer in Zircaloy-4 cladding material Radiograph (top) and Dark field Cut through computed tomogram Transmission spectra of pure Ni, image (bottom) of 1-10 μm layers of showing internal flow channels in an Ni39Cr11, and Inconel 718 powders. steel foil additively manufactured Inconel 718 turbine blade Vertical slice from a neutron microtomography dataset showing Transmission radiographs at different Bragg edge strain map of SANS raw data of microporous dendritic microstructures of lead, stages of lithiation during the discharge additively manufactured Inconel 718 titanium carbide-derived carbon 4 cm x 4 cm x 1 cm thick Al foam voids and gold in a sample of a gold- process. Yellow and green colors at 15, 200, 400 and 550 Mpa. (TiC-CDC) at 800 C (invisible unless measured with lead alloy indicate an increase in Li ion content in gratings) each cathode 10-9 Inferred structure (indirect) Direct structure 0.1Å 1.0nm 0.1mm 1.0 mm 10.0mm 10 cm HFIR CG-1D/MARS (microscopy) FTS VENUS (Bragg edge) FUTURE PROPOSAL HFIR MERCURY (high penetration/large samples) 5 STS CUPI2D (combined Bragg edge and neutron grating interferometry) STS VENUS (Resonance)
Inferred structure (indirect) Direct structure VENUS (FTS epithermal) VENUS (FTS thermal, 2D: hrs Heavy element detection: nuclear 2D: Tens of min to hrs cold) materials, geosciences Phase transformation 30 cm x 30 cm in crystalline materials such as advanced Maximum field-of-view alloys and natural MERCURY (HFIR epithermal) 2D: min proposal materials under Future Difficult to penetrate materials: Life stress, nuclear sciences and biology, large engineering materials, energy materials (H-rich materials, thick and materials large objects), Nuclear materials, etc. One of 8 selected STS 10 cm x 10 cm instruments CUPI2D (STS cold) MARS (HFIR cold) 2D: ms to min 2D: s to min Dynamics: Materials science Thin samples: Micro-defect Current CG-1D (energy materials, alloys, etc.), detections and dynamic processes beamline biology, etc., under extremes in engineered and natural moved to new conditions. materials, magnetic domain position mapping, life sciences and biology 1Å 10 Å 0.5 μm 0.1 mm 0.5 mm 1.0 cm 6 Resolution sensitivity
Neutrons interact uniquely with matter Neutron • Non-destructive • High penetration • Sensitive to light X-ray elements (H, Li, etc.) • Isotopic contrast [M. Strobl et al., J. Phys. D: Appl. Phys. 42 (2009) 243001] https://www.psi.ch/en/niag/what-is-neutron-imaging 7
From raw image to normalized image Lambert-Beer Law Transmission Sample thickness - Normalized Image 1 = = − Raw Dark Field 0 = Attenuation co. Avogadro - 0 constant Transmission Density Open Beam Dark Field = I(i, j) - DF(i, j) I N (i, j) = OB(i, j) - DF(i, j) Total cross-section Molar mass 8
Principle of Bragg edge imaging (using cold neutrons) • Spallation neutron sources discriminate neutron wavelength (or energy) by using the time-of-flight (TOF) technique Wavelength range ~ [1-10 Å] − m ( ) x N A I ( ) = I 0 ( )e m ( ) = t ( ) M 0.55 White-beam (or reactor-based) neutron 0.5 radiograph: (420) Transmission 0.45 sums over all neutron wavelengths 0.4 (220) 0.35 (311) 0.3 (400) 0.25 t1 or λ1 t2or λ2 1.4 1.9 2.4 2.9 tnor λn Wavelength (Angstroms) 1 cm Position of the edge gives the d- spacing of or displacement gives the strain Barton J.P., Bilheux H.Z., Bossi R., Herwig K.W., Santodonato Wavelength-dependent (or TOF) neutron radiographs L., Taylor M., "Chapter 12: Neutron Radiography for (Discrete neutron wavelengths) Nondestructive Testing", Nondestructive Testing Handbook, 9 Fourth Edition: Volume 3, Radiographic Testing (RT) (2019).
VENUS layout and unique capabilities Cave 25 m shielding Detectors Beam path Front-end optics buried in shielding Beam stop Control Hutch Bragg edge imaging: 20 x 20 cm2, spatial resolution ~ 100 µm, time resolution is 5 µs. Resonance imaging: 4 x 4 cm2, spatial resolution ~ 150 µm, time Radiological resolution is 150 ns. Sample area Materials Area (RMA) 10
Preparing for an imaging experiment • Predict overall transmission in your sample (iNEUIT) • Contact instrument team to optimize your experimental measurements (detector, SNR, sample environment, etc.) • Contact computational instrument scientist to discuss data processing and analysis requirements (Python Jupyter notebooks) 11
Experiment planning tools: NEUIT (NEUtron Imaging Toolbox) • Tools available: 1) Neutron transmission Compute white-beam transmission 2) Neutron Resonance Simulate energy-dependent signal 3) Composition convertor Perform wt. % at. % conversion • Nuclear database supported – ENDF/B-VIII.0 (BNL) – ENDF/B-VII.1 (BNL) • Elemental/isotopic info – PeriodicTable 1.5.0 (NIST) 12
NEUtron Imaging Toolbox (NEUIT, https://neuit.sns.gov/ ) For white-beam imaging at CG-1D (static) (demo) 13
NEUtron Imaging Toolbox (NEUIT, https://neuit.sns.gov/ ) For resonance imaging (demo) 14 (static)
Jupyter Notebooks Demonstration • Samples: Ni and Cu powders in Al cans measured at SNS BL-03 SNAP • Goals: – Load and normalized data in iBeatles software – Plot and Identify Bragg edges – Fit Bragg edges – Calculate d-spacing 15
How to get to analysis server and start iBeatles • On a web browser, type “analysis.sns.gov” • Enter username and password • On analysis server, open a terminal window • Type: /SNS/users/j35/bin/start/iBeatles 16
We have a user home page with instructions and tutorials 17
Step-by-step tutorials with animated demonstrations Something you want to see on our user website? Contact Jean Bilheux bilheuxjm@ornl.gov https://neutronimaging.pages.ornl.gov/ 18
This week’s imaging experiment: time-of-flight neutron grating interferometry • International collaboration between: – Markus Strobl and Matteo Busi, Paul Scherrer Institute, Switzerland – Simon Sebold, TUM-FRM-II, Germany – ORNL neutron imaging team • We are measuring the small angle scatter the sample produces when interacting with neutrons: – This is called the dark field imaging technique – We are using a symmetric grating system (i.e., equidistance between the 3 gratings) because it can accept a broad band of neutrons will keeping good visibility 19
This week’s imaging experiment: time-of-flight neutron grating interferometry G0 G1 G2 (25 m period) (12.5 m period) (25 m period) NEUTRONS Sample position 20
G2 (25 m period) Detector Samples NEUTRONS 2 cm 21
Modulation pattern on every detector pixel obtained by stepping G1 perpendicular to beam = Ls /p V = (Imax - Imin)/(Imax + Imin) Grünzweig, C., Quantification of the neutron dark-field imaging signal in grating interferometry. Physical Review B - Condensed Matter and Materials Physics, 88(12), 1–6. https://doi.org/10.1103/PhysRevB.88.125104 Kim, Y.; Valsecchi, J.; Oh, O.; Kim, J.; Lee, S.W.; Boue, F.; Lutton, E.; Busi, M.; Garvey, C.; Strobl, M. Quantitative Neutron Dark-Field Imaging of Milk: A Feasibility Study. Appl. Sci. 2022, 12, 833. https:// doi.org/10.3390/app12020833 22
Example of DFI Data Analysis Visibility is related to real-space correlation For dilute solution of spherical particles Volume Scattering length Radius Cross section fraction density contrast Correlation length Strobl, M. (2015) ‘General solution for quantitative dark-field contrast imaging with grating interferometers’, Scientific Reports, 4(1), p. 7243. Available at: https://doi.org/10.1038/srep07243. Strobl, M. et al. (2016) ‘Wavelength-dispersive dark-field contrast: micrometre structure resolution in neutron imaging with gratings’, Journal of Applied Crystallography, 49(2), 23 pp. 569–573. Available at: https://doi.org/10.1107/S1600576716002922.
Artistic rendering of VENUS Cave Chopper shelf In the spirit of “One ORNL”, VENUS colors are “ORNL-green” and white. 24
CUPI2D’s Current Conceptual Design Optics @26.5m from Elevator No. 2 Optics moderator @18.8m from moderator Elevator No. 1 Pedestal supports Recessed additional flight tube rail system to get as close as Side Access possible to sample provided 25
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