Neutron Imaging Luise Theil Kuhn (Head of Section Imaging and - - PowerPoint PPT Presentation

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Neutron Imaging Luise Theil Kuhn (Head of Section Imaging and - - PowerPoint PPT Presentation

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Neutron Imaging Luise Theil Kuhn (Head of Section Imaging and Structural Analysis) luku@dtu.dk Motivation 2 ISA, DTU Energy, Technical University of Denmark This modules important concepts Instrumentation Radiography ICON, PSI

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Neutron Imaging

Luise Theil Kuhn (Head of Section Imaging and Structural Analysis) luku@dtu.dk

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ISA, DTU Energy, Technical University of Denmark

Motivation

2

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ISA, DTU Energy, Technical University of Denmark

This module’s important concepts

  • Instrumentation
  • Radiography
  • Tomography
  • In operando
  • Virtual Imaging experiment

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T=750 ºC ICON, PSI

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ISA, DTU Energy, Technical University of Denmark

Learning objectives

A student who has successfully completed this module should be able to:

  • Describe how the image and contrast is formed during neutron imaging

and how it differs from X-ray imaging

  • Explain the contributions to the neutron attenuation, and explain the

relationship between the attenuation coefficient and the scattering cross section

  • Explain the principles behind various types of neutron imaging

methodologies

  • Decide which combination of pinhole diameter, pinhole-sample distance,

and sample-detector distance gives the best spatial resolution for a given experimental setup

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ISA, DTU Energy, Technical University of Denmark

Learning objectives

A student who has successfully completed this module should be able to:

  • Decide which of the experimental parameters pinhole diameter, pinhole-

sample distance, and sample-detector distance you should modify to reduce the blur at a given neutron flux and divergence

  • Evaluate the quality of a tomographic reconstruction by applying the

filtered backprojection algorithm

  • Evaluate the advantages of neutron radiography compared to neutron

tomography

  • Give design principles for a neutron imaging setup for 2D and 3D analysis
  • f a given type of sample

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ISA, DTU Energy, Technical University of Denmark 6

Image and contrast formation

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ISA, DTU Energy, Technical University of Denmark

Image and contrast formation

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Absorption Scattering

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ISA, DTU Energy, Technical University of Denmark

Radiography

8 Strobl, M. et al. (2009). J. Phys. D. Appl. Phys. 42, 243001.

µ(x)dx µ(x)

Beer-Lambert law:

µtotal=µa+ µs

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ISA, DTU Energy, Technical University of Denmark

Setup: ICON @ PSI

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ISA, DTU Energy, Technical University of Denmark

Spatial resolution

10 Strobl, M. et al. (2009). J. Phys. D. Appl. Phys. 42, 243001.

d

l d L D 

L

l

D

L – Distance Collimator-Object l – Distance Object-Detector D – Collimator aperture, pinhole

Source Collimator Detector Object

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ISA, DTU Energy, Technical University of Denmark

Spatial resolution - Siemens star

11 Trtik, P. et al. (2015). Physics Procedia. 69, 169.

32.9 mm 7.6 mm

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ISA, DTU Energy, Technical University of Denmark

Detectors

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Charged Coupled Device Multi Channel Plate

http://www.novascientific.com/technology/

CCD

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ISA, DTU Energy, Technical University of Denmark

Principle for data acquisition in imaging experiment

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  • 1. Raw image, Iθ
  • 2. Dark field image (no beam), correct for

dark-current in detector system, DF

  • 3. Flat-field image (open beam), correct

for inhomogeneities in beam-profile and in detector screen, FF

  • 4. Image, Tθ
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ISA, DTU Energy, Technical University of Denmark

Tomography

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2D sample Projection image Tθ Sinogram

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ISA, DTU Energy, Technical University of Denmark

Tomographic reconstruction

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ISA, DTU Energy, Technical University of Denmark

Fourier Slice Theorem

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ISA, DTU Energy, Technical University of Denmark

Principle for tomographic reconstruction

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  • 1. Collect projections, Pθ(x’), for several angles
  • 2. Calculate the Fourier transform of each projection
  • 3. Apply the filter to Fourier domain to approximate the

ideal case

  • 4. Find the inverse Fourier transformation of the filtered

projection

  • 5. Sum over all angles to make the reconstruction

4 projections 8 projections 32 projections 128 projections

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ISA, DTU Energy, Technical University of Denmark

Cases: Proton Exchange Membrane Fuel Cell (PEMFC)

18 Mischler, J. et al. (2010). Electrochimica Acta. 75, 1.

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ISA, DTU Energy, Technical University of Denmark 19 Manke, I. et al. (2009). Appl. Phys. Lett. 92, 244101.

Cases: in situ study of water in PEMFC

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ISA, DTU Energy, Technical University of Denmark

Cases: water uptake in plants

20 Strobl, M. et al. (2009). J. Phys. D. Appl. Phys. 42, 243001.

0.25h 0.5h 6h 12h

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ISA, DTU Energy, Technical University of Denmark

Cases: Alkaline battery Li-air battery cathode

21 Nanda, J. et al. (2012). J. Phys. Chem. C. 116, 8401. Strobl, M. et al. (2009). J. Phys. D. Appl. Phys. 42, 243001.

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ISA, DTU Energy, Technical University of Denmark

Cases: Soot in particulate filter for diesel engine

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https://www.psi.ch/media/distribution-of-soot-particles- in-particulate-filters-of-diesel-vehicles

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ISA, DTU Energy, Technical University of Denmark

Cases: Cultural heritage

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ISA, DTU Energy, Technical University of Denmark

Energy-resolved neutron imaging Bragg-edge imaging

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Total neutron cross section for different polycrystalline materials

2dhklsinθ=l 2dhklsin90°=l 2dhklsinθ< l

𝑪𝒔𝒃𝒉𝒉′𝒕 𝒎𝒃𝒙:

Josic, L. et al (2011). Nucl. Instruments Methods Phys. Res. 651, 166.

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ISA, DTU Energy, Technical University of Denmark

Energy-selective neutron imaging Case: welding of steel

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3.4 Å 4.0 Å 4.4 Å

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ISA, DTU Energy, Technical University of Denmark

In situ Bragg-edge imaging linking strain and reduction in Solid Oxide Cell electrode supports

26 17 September, 2017

T=750 ºC

  • M. Makowska et al, J.Appl.Cryst. 48, 401(2015)
  • M. Makowska et al, J. Appl. Cryst. 49, 1674 (2016)
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ISA, DTU Energy, Technical University of Denmark

Neutron Bragg-edge tomography of crack evolution after 5x red-ox cycling

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NiO Ni

17 September, 2017

  • M. Makowska et al, submitted (2017)

1 mm

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ISA, DTU Energy, Technical University of Denmark

Neutron grating interferometry

28 Grünzweig, C. et al. (2008). Appl. Phys. Lett. 93, 112504. Grünzweig, C. et al. (2006). Phys. Rev. Lett. 96, 215505.

Ti Pb Mo Mg

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ISA, DTU Energy, Technical University of Denmark

3D polarimetric neutron tomography of magnetic fields and current distributions

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  • M. Sales et al, submitted (2017)
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ISA, DTU Energy, Technical University of Denmark

Summary

30 Lehmann, E. et al. (2017). Phys. Proc. 88, 5.

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ISA, DTU Energy, Technical University of Denmark

Acknowledgments

31

  • M. Makowska (now FRM II, Münich), M. Lacatusu,
  • H. Lund Frandsen, L. Nilausen Cleemann
  • S. Koch, J. Johnsen

17 September, 2017

  • E. Mejdal Lauridsen
  • S. Schmidt, M. Sales
  • R. Woracek, N. Kardjilov
  • S. Kabra, W. Kockelmann
  • A. Tremsin
  • M. Strobl
  • M. Morgano
  • R. Woracek

Takenao Shinohara Petr Sittner

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ISA, DTU Energy, Technical University of Denmark

In situ Bragg-edge imaging of red-ox cycling (750 ⁰C) of Solid Oxide Cell electrode supports

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Initial oxidized state After reduction After reduction After oxidation After oxidation

Initial oxidized state

Reduced

NiO Ni

20 mm

Macroscopic cross section [1/mm]

17 September, 2017

  • M. Makowska et al, J. Power Sources 340, 167 (2017)