Radial collimators and neutron guide at STRESS- · PDF fileRadial collimators and neutron...

Technische UniversitätMünchen

Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II)

Radial collimators and neutron guide at STRESS-SPECW. Gan (1), J. Rebelo Kornmeier (2), M. Hofmann (2)

(1) Helmholtzzentrum Geesthacht, GKSS, Geeshacht, Germany(2) Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU München, Garching, Germany



Outline

• Setup & new things (robot, stress-rigs...)

• Radial collimators Minimisation of spurious strains Spatial resolved phase analysis

• Neutron guide• Summary



• Large area detector• 3 Monochromators

– Si(400)– Ge(511)– PG(002)

+ 2M = 35°-110°

1. Optimise: Neutron flux - resolution 2. = 1 – 2.4 Å3. 2 = 90 possible (cubic gauge volume!)

STRESS-SPEC



Strain mappingTexture

Large Samples

Surface strains

STRESS-SPECTypical examples

Phase analysis –transformation kinetics

in-situ experiments(welding)



• sample table– 300 kg load capacity– xy = +/- 125 mm,

z = 300 mm• Eulerian cradles + Robot• 2x Test rigs (+/- 50 kN) and

torsion (100 Nm) + T upto 1000°C

• accurate + variable slit system: 0.5x0.5x0.5 mm³ - 5x5x20 mm³+ radial collimators available

STRESS-SPECAncillaries

+/- 47°



STRESS-SPECRadial collimators

Since 2011 3x oscillating collimators: 1, 2 and 5 mm FOV large acceptance angle matched to detector



Minimisation of spurious strainsJ. Rebelo-Kornmeier (TUM), J. Saroun (NPI, Rez)



R

F

A

M B

M

∆λ/ λ = ∆α1·(1 - LMS/(R·sinθM)) · cotθM

geometric

wavelength

M. Vrána, P. Mikula, Nucl. Instr. Mezh. A338 (1994) p125

Ge, mosaic

‐0.002

‐0.001

0.000

0.001

0.002

‐2.5 ‐1.5 ‐0.5 0.5 1.5 2.5

∆d/d

Position of pin [mm]

WL

geo

‐0.003

‐0.002

‐0.001

0.000

0.001

0.002

0.003

‐2.5 ‐2 ‐1.5 ‐1 ‐0.5 0 0.5 1 1.5 2 2.5

∆d/d

Position of pin [mm]

R = 4m (WL)R = 4 m (geo)R = 5.5 m (WL)R = 5.5 m (geo)R = 6.5 m (WL)R = 6.5 m (geo)

Si, elastically bent

PSD



Experiment

• 2M = 76 , λ = 1.68Å• stress free steel sample (S690QL) 50 x 50 x 10 mm• Fe(211) ≈ 2 = 90 / [Fe(110), Fe(200), Fe(220)]• 2 mm radial collimator in secondary beam path minimise peak clipping

variation of thebending radius R between 2 .. 12 m

Slits

sample

PSD detector

M S

Si-monochromator

Radial collimator

1

sin12

MM

MS

M

SMS R

Ltgtg

S

MM

MSM

tgtg

LR

21sin

s=0

M. Vrána, P. Mikula, Mat. Sci. Forum 490-491 (2005) p234



min surf strain



Analytical and numerical simulations

Šaroun, J., Kulda J., RESTRAX, in Modern Developments in X-Ray and Neutron Optics, eds. A. Erko,M. Idir, T. Krist, A.G. Michette, Springer Berlin 2008, p. 57-68.

sample

Radial collimator

detector

monochromator

Analytical (A. Stoica, Acta Cryst. A31 (1975) 189)

Ray-tracing simulation of instrument set-up STRESS-SPEC-- SIMRES version 6.0.9 (very quick)



= 1.68 Å



Measurements + MC simulations

Position GV centre [mm] Position GV centre [mm]



• ND from bulk to surface (~ 250 µm) • comparison with x-ray data

• 2 mm radial collimator• hot forming tool steel AISI H11

Hot metal forming steel tool

after 200 cycles

A. Gruening et al, 2011, Conf. Proceedings Society Experimental Mechanics Series, 39-45



Direct measurements – deep rolling

-1200

-1000

-800

-600

-400

-200

0

200

0 200 400 600 800 1000 1200 1400

Res

idua

l Str

ess

[N/m

m²]

Distance from Surface [µm]

parallel to rolling directionprependicular to rolling directionnormal to surface

• steel 42CrMo4• deep rolling 320 bar• 1 mm radial collimator

Xray data – open symbols



Spatial resolved phase analysis in Na/MCl2 (ZEBRA)-batteries

R. Gilles (TUM), Y. Gao, J.T. Rjiessenbeck (GE, USA)



C.H. Dustmann, J. Power Sources 127 (2004) 85



Spatially resolved neutron diffraction – instrumental setup

Radial collimator (FWHM = 2 mm)

Primary Slits (2 x 20 mm2)

2

Stress-Spec, FRM II

= 2.014 Å2range = 35 -110°

Fe/NaCl battery cell– half charged (20 Ahr)

Neutrons



FeFeCl2

FeCl2

NaAlCl4

Pos -17.5 mm

FeFe

“ alumina

Pos -10 mm

NaClNaCl

NaAlCl4

Fe

Na6FeCl8

Na ?

Pos -20 mm



Phase distribution - diagonal

0

10

20

30

40

50

60

70

-20 -10 0 10 20

Phas

e fr

actio

ns in

Gau

ge V

olum

e [%

]

Position [mm]

Fe

Na6FeCl8

NaAlCl4FeCl2

“ -alumina



Focusing (Vertical) Neutron Guide



sample

detector

monochromator

neutron guideL = 1.0 m

- enhance vertical gauge volume definitionat largee optics-sample distances

- increase flux

dete

ctor



1000 mm

Multi-channel parabolic guide

Coating inner walls: m=3Top walls: m0/absorbing

3

3.1

3.2

3.3

3.4

3.5

3.6

3.7

0

50

100

150

200

1 1.2 1.4 1.6 1.8 2 2.2 2.4

Wid

th o

f Foc

us [m

m]

Focu

s fr

om e

xit [

mm

]

[Å]



Comparison Conventional Slit – Guide(λ = 1.68 Å)

Guide Slit

Distance Sample – Slit/Gauge 120 mm

10 mm

12 m

m

0

0.5

1

1.5

2

2.5

3

3.5

4

0 50 100 150 200FW

HM

nor

mal

ised

Distance Sample - Slit/Guide [mm]

Slit Horiz.Guide Horiz.Slit ver.Guide ver.



Across 2 mm of the GV (vertical direction)

GuideSlit

Slit Guide



0

500

1000

1500

2000

2500

3000

‐6 ‐4 ‐2 0 2 4 6

Intensity

[a.u.]

FWHM [mm]

measuredsimulated

0

500

1000

1500

2000

2500

3000

3500

‐6 ‐4 ‐2 0 2 4 6

Intensity

[a.u.]

FWHM [mm]

measuredsimulated

0

500

1000

1500

2000

2500

3000

3500

4000

‐6 ‐4 ‐2 0 2 4 6

Intensity

[a.u.]

FWHM [mm]

measuredsimulated

Simulation: McStas

Vertical cut through GVat

0 mm50 mm120 mm



Strain measurement on welded plateComparison Guide – Published data

(Int. J. Pres. Vessels & Piping 86 (2009) 125)

0

100

200

300

400

500

600

700

800

98 99 100 101 102 103 104 105

Cou

nts/

300s

ec.

TwoTheta [°]

Guide

Slit

FWHM = 0.53°

FWHM = 0.51°

-1500

-1000

-500

0

500

1000

1500

2000

-100 -50 0 50 100

Stra

in

[µm

/m]

Distance [mm]

Long Norm



Summary

• Radial collimators are useful optical tools for materialsscience diffractometers (not only for large samples)

• Neutron guide: can be used to increase flux better definition of GV (vertical)



Thanks to

J. Kornmeier TUMW. Gan GKSSG. Seidl TUMU. Garbe AnstoH.G. Brokmeier TU ClausthalC. Randau TU ClausthalM. Völler TUM

J. Saroun NPI, Rez

J. Gibmeier TU Karlsruhe

Y. Gao GE, USAJ. Rjiessenbeck GE, USA



magazine Sample changer PTM CXC10 withholders



+/- 47°

Austenite (200) - polfigures



Direct measurements – shot-peened steel sample

Xray data from: Mat. Sci. Forum, 404-407 (2002) 659

• shot-peened steel SAE 4140• dimensions 50 x 50 x 10 mm³• 2 mm radial collimator

J. Rebelo Kornmeier et al. Materials Science Forum 681 (2011) 399 J. Rebelo Kornmeier et al. Meas. Sci. Technol. 22 (2011) 065705

Radial collimators and neutron guide at STRESS- · PDF fileRadial collimators and neutron...

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