advances in neutron radiography and tomographyxrsi.cmit.csiro.au/tomowkshop/pdfs/banhart.pdf · aus...

formerly

Hahn-Meitner-Institute

and

Advances in NeutronRadiography and TomographyJ. Banhart currently: CSIRO ClaytonN. Kardjilov Instrument scientist tomographyA. Hilger PhD studentI. Manke Head of tomography groupM. Dawson Postdoc in tomographyT. Kandemir StudentM. Strobl Postdoc in neutron diffraction

AUS TOMO II Workshop, Melbourne 13.-14.11.2008

Advances in neutron radiography and tomography

22

Hahn-MeitnerReactor

20 km

BESSY II

Location of Institute



3

Application Centre Tomographic Methods

Neutron tomography

X-ray tomography and microscopy

2 µm

Focused Ion Beam-Tomography

14x14x253nm3

3D atom probe

40 nm

Electron tomography

1 m10 mm0,1 mm1 µm10 nm1Å



4

Contents

� Neutron absorption imaging� principles� optimisation of beam and detection system

� Applications� fuel cell, combustion chamber, spark plug,

cellular materials, battery

� Alternative contrast mechanisms� energy scanning � (phase contrast and dark field imaging)� use of polarised neutrons



5

X-ray radiography



6

Neutron radiography in early days

Taken from C.O. Fischer’s article in WCNR-4

Berlin, 1935 – 1938H. Kallmann & Kuhn with Ra-Be neutron generator

Berlin, until Dec. 1944O. Peter with anaccelerator neutron source

More sophisticated programs with neutrons after WW II at the research reactor in Harwell (UK)

Comparison between X-ray and neutron images: valves , manometers, injectors

Renewed interest since about 1995



7

Comparison between X-rays and neutrons

X-Rays

A

B

Photoelectron

Absorption

Incident x-ray photon with energy E0

Scattering

0 20 40 60 80 10010-2

100

102

Mas

s at

tenu

atio

n co

effic

ient

, (cm

2 /g)

Atomic number

X-rays (100 keV)

nucleus

nikolay1



8

Comparison between X-rays and neutrons

Neutrons

A

B

Absorption

Incident neutron with energy E0

Scattering

nucleus

0 20 40 60 80 10010-2

100

102

Fe

Mas

s at

tenu

atio

n co

effic

ient

, (cm

2 /g)

Atomic number

X-rays (100 keV) Thermal neutrons

Gd113Cd10B

Li

2H

1H

CoNi

Pb

Au

LightElements

MetalsHeavyElements

nikolay4

nikolay1 Kardjilov, 29/05/2005

Slide 8

nikolay4 Kardjilov, 29/05/2005



9

Contrast

Resolution

• given by beam characteristics• often limited by detector

• given by neutron interaction with matter

Contrast and Resolution



10

Neutron imaging - contrast

Neutrons: hydrogen-containing parts appear dark, metal light grey

X-rays: thicker metallic components are hard to penetrate, hydrogen-containing parts hardly visible



11

Inspection of a car door with neutrons

►the metallic parts are transparent

►the adhesive bonds can be inspected easily

photograph neutron image

Inspection of car parts

Courtesy of E. Lehmann, PSI (CH)



12

Principle of conventional radiography

d

ld

L D=

L l

D

L – Distance Collimator-Object

l – Distance Object-Detector

D – Collimator aperture

Source Collimator DetectorObject



13

Resolution: dependence on l

3,5" floppy drive images with l = 0 cm 10 cm and 20 cm distance,detection: film + Gd sandwich, cold neutron guide with L/D=71.

B. Schillinger, FRM-I

increasing l



14

Resolution: dependence on L/D

L/D=71 L/D=115 L/D=320 L/D>500

increasing L/D

B. Schillinger, FRM-I

But: higher L/D implies lower flux and longer exposition time

Neutron radiographs of a small engine



15

Neutron tomography at the Hahn-Meitner Reactor

V7 (CONRAD)

Experimental hall forthermal neutrons

Neutron guide hall forcold neutrons



16

position II

Beam optimisation

• flux: ~107 n / (cm2s)

• beam size : 10 × 10 cm2

• L/D: 500, 250, 167

wavelength 0.2 - 1.0 nm

1 m

Top view



17

position I

Beam optimisation

• flux: ~2 × 108 n / (cm2s)

• beam size: 12 × 3 cm2

• L/D ~ 70

wavelength 0.2 - 1.0 nm

1 m

Top view



18

position Iposition II

Beam optimisation

• flux: ~107 n / (cm2s)

• beam size : 10 × 10 cm2

• L/D: 500, 250, 167

Position II Exposure time: 15 sL/D ratio: ca. 400

1 cm

running engineat 6000 rpm

stroboscopic techniqueexposure time: 1 msaccumulation: 500 x

Position IExposure time: 0.5 sL/D ratio: ca. 70



1919

500 400 300 200 100 µm

Standard setup Improved lenses + Improved screenScintillator: 200 µm 6LiFLens system: 50 mmPixel size: 100 µmExposure time: 20 s

Scintillator: 200 µm 6LiFLens system: 105 mmPixel size: 30 µmExposure time: 20 s

Scintillator: 5 µm GadoxLens system: 105 mmPixel size: 30 µmExposure time: 120 s

100 µm

60 µm

Detector optimisation – qualitative estimation



20

6Li+ZnS 400 1926Li+ZnS 200 1376Li+ZnS 100 1086Li+ZnS 50 72Gadox 30 76Gadox 20 58Gadox 10 52Gadox 5 48

Gadox 30 61Gadox 20 33Gadox 10 27Gadox 5 25

Scintillatormaterial

Spatial resolution [μm]

Scintillatorthickness [μm]

105 mm lens

200 mm lens

Detector optimisation

FOV : 60 x 60 mm2

FOV : 27 x 27 mm2



21

Comparison X-ray / neutrons

Microfocus X-ray scanner

Pixel size: 23 µm

Flat panel

Cold neutrons

Pixel size: 30 µm

Lens: 105 mm

Scintillating screen: 10µm Gadox

1 cm



22

Fuel cells

Polymer electrolyte fuel cell

• Nafion membrane

• carbon fibre Gas Diff. Layer

• typ. 100 cells in a stack



23

In-situ neutron radiography: fuel cells

neutron radiography (fast motion)

operating fuel cell applying realistic power profilesPEM fuel cell

14 cm L/D 167, ~ 108 n/cm 2s, ∆∆∆∆T = 10 s

liquid water accumulation ⇒ gas flow in the channels hinderedwater management: a major challenge for PEM fuel cells



Fuel cell: neutron tomogram of stopped triple-stack cell



Fuel cell: neutron tomogram of water in flowfield channe ls

I. Manke, C. Hartnig, N. Kardjilov, A. Hilger, J. B anhart et alQuasi-in situ neutron tomography on polymer electrolyte membrane fuel cell stacksApplied Physics Letters 90, 184101 (2007)



26

Neutron tomography: fuel sediments in combustion ch amber

2 cm

Fuel sediments



27

X-ray tomographyNeutron tomography

Glue between spheres Steel hollow spheres

Complementarity of neutrons and X-rays



28

Neutron tomography X-ray tomography

Highly absorbing regions: hydride remnants?

Complementarity of neutrons and X-rays



29

Partially dischargedca. 1,3V

Fully charged1,6V

Examples: battery discharge

Neutrontomography

X-raytomography

KOH, H2O

Steel container

H+I. Manke et al., Appl. Phys. Lett.90, 214102 (2007)



30

Beam monochromatisation

polychromaticbeam

monochromaticbeam

Double crystal monochromator: PCG crystals (mosaicity of 0.8°)

Range: 2.0 – 6.5 Å

Band width (∆λ/λ): ~ 3%

Neutron flux: ~ 4x105 n/cm2s (at λ=3.0 Å)

Beam size: 5 x 20 cm2



31

Coherent scattering – Bragg edges

dhkl

2dhklsinθ=λpolychromatic neutron beam

polycrystallinematerial

Bragg‘s law

DCM

λ

2 θ



32

polychromatic neutron beam

DCM

λ

Coherent scattering – Bragg edges

2dhklsin90°=λdhkl

2dhkl=λ (110)

polycrystallinematerial

Bragg‘s law

Cross-sections of iron per atom



33

Energy scanning radiography

Welded joint (photo)

3.8 Å 4.0 Å 4.2 Å

1 cm *Collaboration work with PSI, Switzerland

2 3 4 5 6 70.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Atte

nuat

ion

coef

ficie

nt, Σ

[cm

-1]

Wavelength [Å]

Fe (110)



34

2 3 4 5 6 70.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Atte

nuat

ion

coef

ficie

nt, Σ

[cm

-1]

Wavelength [Å]

Fe

θ

θ

ββββhkl

dhkl

−=

hklhkl d2

arcsin2

λπβ

(110)

2 4 6

-2

0

2

Wavelength [Å]

Data: Derivative1_Eisen0059GModel: GaussEquation: y=y0 + (A/(w*sqrt(PI/2)))*exp(-2*((x-xc)/w)^2)Weighting: y No weighting Chi^2/DoF = 0.24436R^2 = 0.5796 y0 0.2702 ±0.07067xc 4.00941 ±0.02468w 0.31818 ±0.05082A -1.03499 ±0.15132

Derivative of Eisen0059_G Gauss fit of Derivative1_Eisen0059G

Energy scanning radiography



35

Quantitative texture analysis

35



36

Neutrons

Spin polariser Spin analyser

2D-detector

Spin

Magnet

B-field

N Sϕ

Spinrotation

x

y

z

Neutrons


2D-detector

Spin

Magnet

B-field

N Sϕ

Spinrotation

x

y

z

Polarised neutron imaging

Principle

Experimental parameters

• Solid state polarizing benders

• Beam size (WxH): 20 x 4 cm2

• Exposure times: ~10 min / image

∫==path

LL Hds

vt

γωϕ

1 cm

permanent magnet



37

Neutrons


2D-detector

Spin

Magnet

B-field

N Sϕ

Spinrotation

x

y

z

Neutrons


2D-detector

Spin

Magnet

B-field

N Sϕ

Spinrotation

x

y

z


Principle


• Solid state polarazing benders


• Exposure times: ~10 min / image

Al slab



38

Neutrons


2D-detector

Spin

Magnet

B-field

N Sϕ

Spinrotation

x

y

z

Neutrons


2D-detector

Spin

Magnet

B-field

N Sϕ

Spinrotation

x

y

z


Principle


• Solid state polarazing benders


• Exposure times: ~10 min / image 1 cm

non-dipole magnets

Al slab



39

Polarised neutron tomography

7.0 K

7.2 K

6.9 K

1 cm

Pb cylinder(polycrystalline)

T

7.196 K (Tc)

7.0 K

Example: Flux Trapping

Tomographyrotation

axis

trappedflux

N. Kardjilov, I. Manke, M. Strobl, A. Hilger, W. Treimer, Th. Krist, M. Meissner, J. Banhart, Nature Physics 4, 399-403 (2008)



40

Access to neutron tomography instrument CONRAD

� http://www.hmi.de/bensc/

� Next proposal deadlines: 15th March and 15th September 2009

� Online proposal submission: https://www.hmi.de/pubbin/bensc_club.pl

2005/I 2005/II 2006/I 2006/II 2007/I 2007/II 2008/I 2008/II 2009/I0.0

0.5

1.0

1.5

2.0

Load

fact

or fo

r ex

tern

al p

ropo

sals

Load factor for the neutron imaging beamline CONRAD at HZB



AUS TOMO II Workshop, Melbourne 13.-14.11.2008 41

1. Some Mathematical Concepts for Tomographic Reconstruction

2. Visualisation, Processing and Analysis of Tomographic Data

3. Radiation Sources and Interaction of Radiation with Matter

4. Synchrotron X-ray Absorption Tomography

5. Phase Contrast and Holographic Tomography

6. Tomography using magnifying optics7. Scanning X-ray Tomography8. Three-dimensional X-ray Diffraction

(3DXRD)9. Detectors for Synchrotron Tomography10. Fundamentals of Electron Tomography11. Applications of Electron Tomography12. Neutron Absorption Tomography13. Neutron Phase Contrast and Polarised

Neutron Tomography14. Neutron Refraction and Small-Angle

Scattering Tomography



42

Thank you !Further questions and discussions?

→ [email protected] (until 03/09)→ [email protected] (after 04/09)

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