Pavol Mikula al. Nuclear Physics Institute, 250 68 e Czech Republic - - PowerPoint PPT Presentation

Kuala Lumpur, July 2-4, 2009, 2nd RCM of the IAEA F1-RC-1056.1

• n „Improved production and utilization of short pulsed, cold neutrons

at low-medium energy spallation neutron sources” Pavol Mikula al. Nuclear Physics Institute, 250 68 Řež Czech Republic

Our main task within the contract 14198 : Development and optimization of a curved wide- wavelength band monochromator based on strongly cylindrically bent perfect Si-slabs in a sandwich for microfocusing small-angle neutron scattering (mfSANS) device

The main research task on the side of NPI Řež was preparation of crystal slabs for a sandwich type monochromator for a newly designed compact SANS instrument as proposed by Hokkaido University (prof. M. Furusaka) which would permit us to demonstrate a new type of inexpensive instrument which can be designed and realized for operation at different neutron wavelengths. Our laboratory has to provide know-how in the design and optimization performance of the required wide wavelength band focusing monochromators. Furthermore, our laboratory has to provide Si- perfect crystals of a special cut for cylindrical bending.

Neutron production

Reactor LVR 15, NRI Řež, CZ

• reactor power 10 MW
• thermal flux in the core 1.5 1018 ns-1m-2
• beam tube 1 1013 ns-1m-2
• fuel enrichment 36% 235U
• tank type
• light water moderated and cooled

Experimental facilities installed at the reactor LVR-15 in Řež

NBCT

1 2 m

SANS multipurpose diffractometer

strain scanner I

NDP powder diffractometer Radiative capture

powder

diffractometer

strain

scanner II

Neutronový difractometr SPN 100

Detector unit Monochromator drum Sample

What we have done?

For Hokkaido University Two sets (2x30) of the perfect silicon crystal slabs of a special cut with the lattice planes (111) at the angle 67.5 deg have been prepared. The dimensions of the slabs are: 120x20x0.5 mm3 (length x width x thickness). Therefore, such a cut of the crystal slabs permits us to use the bent focusing monochromator in the so called fully asymmetric diffraction geometry when employing it just at the Bragg angle of 67.5 deg. Two sets (1x30 and 1x40) of the crystal slabs of the same orientation which will be used for mechanical tests (minimum curvature, optimum number of slabs in the sandwich) have been prepared. For HMI Berlin Two horizontally and vertically focusing monochromators and three sets of Si crystals with the main face parallel to 311, 331 and 400 lattice planes. For KAERI Daejeon One horizontally focusing monochromators and 17 Si crystal slabs of different cut. For JINR Dubna One horizontally focusing monochromators and Si(220) and Si(111) crystal slabs.

Collaborative works

Horizontally and vertically focusing monochromator manufactured for HMI. 2 pieces, with Si(311) and Si(400) planes, figure of merit increased 10x. Horizontally focusing monochromator manufactured for KAERI different thicknesses of the Si(111) crystals and different asymmetric geometries.

Monte Carlo simulations

KAERI Daejeon CIAE Beijing NECSA, South Africa JINR Dubna – Kurchatov Inst. Moscow

Future plans and collaboration

We are developing a long term collaboration with KAERI Daejeon. Within 2009/10 we have to prepare two new horizontally focusing monochromators including Si(111) slabs of different thicknesses Construction of the horizontally and vertically focusing mono-chromator for CIAE Beijing for China Advanced Research Reactor Construction of the horizontally and vertically focusing monochromator for Mirrotron Budapest manufacturing whole stress diffractometer for Mianyang institute in Sichuan Construction of the horizontally focusing monochromator for BARC Mumbai (bending device ready, crystals in preparation) Construction of the horizontally focusing monochromator for Malaysian Nuclear Agency Monte Carlo simulations for KAERI Daejeon After clarifying some problems related to the lower efficiency of the present monochromator, new sets of crystals will be prepared for HU.

SANS instrumentation

Double-crystal system – slit geometry

Double-bent-crystal high-resolution SANS camera Ultra high-resolution Bonse-Hart SANS camera

At home

Reconstruction of the high resolution small-angle neutron scattering double crystal diffractometer:

• New collimator with the saphire filter
• New monochromator shielding
• Improved shielding between individual instruments
• Improved sample environment

Reconstruction of the multipurpose neutron diffractometer:

• New detector arm (Huber)
• PSD detector
• New monochromator shielding
• Improved shielding between individual instruments

SANS Instrumentation

SANS technique

size range

Collimator instruments

1 nm .. 100 nm

DC diffractometers with bent crystals

10 nm .. 1 µm

DC diffractometers with perfect crystals (Bonse-Hart)

1 µm .. 10 µm

Developed experimental

technique

Advanced data evaluation

method & software − multiple scattering − Non-linear data fitting

• f a single model to

multiple data sets

Double-Crystal SANS Diffractometer DN-2

beam shutter position sensitive detector beam tube with collimator samples bent Si 220 bent Si 111 analyzer (asymmetric cut)

PE + B Pb

bent Si 111 diffraction planes 111 steel rods

∆ θ ∆θ x R L

D A D S

= ( sin(2 ) + )

∆θS ∆xD L

D

Instrument Parameters

Monochromator bent perfect crystal Si 111 symmetric geometry Sample maximum 5x25 mm2 Analyzer bent perfect crystal Si 111 fully asymmetric geometry Detector 1-dimensional 3He PSD resolution ~ 1 mm Wavelength λ = 2.1 A, ∆λ/λ < 0.01 Neutron flux 5⋅103 n s-1 cm-2 / RM = 300 m 4⋅104 n s-1 cm-2 / RM = 35 m Q-resolution 1⋅10-4 A-1 / RM = 300 m 1⋅10-3 A-1 / RM = 35 m Vertical Q-resolution 10-1 A-1 Total Q-range 2 10-4 ÷ 2 10-2 A-1

SANS-Diffractometer in NPI

Small-angle neutron scattering

0.01 0.1 1 20 40 60 80 100 120 140

as sprayed 1300

• C

1520

• C

1730

• C

D(R) [10

• 2 µm
• 1]

R [µm]

0.1 1 5 10 15

1 10 100 0.01 0.1 1 10 100 1000 10000 z=5 mm z=2.5 mm empty beam

T=1730

• C

z dΣ/dθ

Qx [ µm

• 1]

Bonse-Hart

Collimator instruments

Study of porosity in plasma-sprayed ceramics

Size distribution of pores in plasma-sprayed Al2O3 SANS data for various resolutions and sample thickness fitted to a single model.

The most recent results Experimental powder diffraction test at a small take-off angle

Bent perfect crystal monochromator PSD detector 40 mm width α-Fe sample 2 mm diameter

Experimental test

Monochromator take-off angle 30o. No collimators were used.

PSD detector 2θ=30 deg B P C-monochromator

Ψ

PSD detector 2θ=30 deg B P C-monochromator

Ψ

PSD detector 2θ=30 deg BP C-monochromator

Ψ

PSD detector 2θ=30 deg BP C-monochromator

Ψ=0 deg

Diffraction geometries

Asymmetric transmission geometry, OBC Symmetric reflection geometry

Ψ= 22o, t=4mm Ψ = 29.5o, t=3 mm Ψ = 35.26o, t=4mm Ψ = 0o, t=4 mm Ψ = 0o, t=3x1.3 mm Ψ = 0o, t=1.3 mm

Spatial resolution of the PSD – 2 mm 1 channel = 0.009o

• 30-20-10 0 10 20 30

50 100 150 200

• 30-20-10 0 10 20 30

50 100 150 200

• 30-20-10 0 10 20 30

50 100 150 200 Si 111, chi=29.5, 1/Ropt=0.29 Intensity [n/s] x [mm] Ge 111, chi=29.5, 1/Ropt=0.31 x [mm] Si 111, chi=35.26, 1/Ropt=0.33 x [mm]

• 30-20-10 0 10 20 30

50 100 150 200 Si 111, chi=22, 1/Ropt=0.26 Intensity [n/s] x [mm]

• 30-20-10 0 10 20 30

50 100 150 200 Si 111, chi=48.53 1/Ropt=0.40 x [mm]

• 30-20-10 0 10 20 30

50 100 150 200 Si 111, chi=-48.53 1/Ropt=-0.25 x [mm]

MC simulations (output beam expansiom)

• 30-20-10 0 10 20 30

50 100 150 200 Si 111, chi=0, 1/Ropt=0.11 x [mm]

MC simulations (output beam compression)

• 30
• 20
• 10 0 10 20 30

50 100 150 200

• 30
• 20
• 10 0 10 20 30

50 100 150 200

• 30
• 20
• 10 0 10 20 30

50 100 150 200 Si 111, chi=-29.5, 1/Ropt=-0.11 Intensity [n/s] x [mm] Ge 111, chi=-29.5, 1/Ropt=-0.11 x [mm] Si 111, chi=-35.26, 1/Ropt=-0.155 x [mm]

• 30
• 20
• 10 0 10 20 30

50 100 150 200 Si 111, chi=-22, 1/Ropt=-0.05 Intensity [n/s] x [mm]

• 30
• 20
• 10 0 10 20 30

50 100 150 200 Si 111, chi=-48.53 1/Ropt=-0.24 x [mm]

• 30-20-10 0 10 20 30

50 100 150 200 Si 111, chi=0, 1/Ropt=0.11 x [mm]

Experimental results: Asymmetric transmission geometry (OBC)

140 160 180 200 220 240 54 56 58 60 62

FWHM Peak height

Bending /µm FWHM / channel numbers

si(111) Ψ=35.26 deg Output beam compression 200x40x4 mmm

800 820 840 860 880 900 920

Peak height

40 60 80 100 120 140 50 55 60 65 70 75

si(111) Ψ=22 deg Output beam compression 200*30*4

FWHM Peak height

Bending / µm FWHM / channel numbers

500 550 600 650 700 750

Peak height

100 120 140 160 180 200 45 50 55 60

FWHM Peak height

Bending / µm FWHM / channel numbers

Ψ =29.5 deg

Output beam compression 200x30x3 mm

600 650 700 750 800

Peak height

90 100 110 120 130 140 150 160 170 180 50 60 70 80 90 100 110

FWHM Peak height

Bending / µm FWHM / channel numbers

Si(111) Symmetric reflection 200x40x4 mm

1500 2000 2500 3000 3500

Peak height

60 70 80 90 100 110 50 60 70 80 90 100

FWHM Peak height

Bending / µm FWHM / channel numbers

Si(111) sandwich Symmetric reflection 200*40*3x1.3 mm

1600 1800 2000 2200 2400 2600

Peak height

Experimental results: Symmetric reflection geometry

80 90 100 110 120 130 30 40 50 60 70 80

FWHM Peak height

Bending / µm FWHM / channel numbers

Si(111) Symmetric reflection 200*40*1.3 mm

600 900 1200 1500 1800

Peak height

200 300 400 100 200 300 400 500

y0 31.57447 ±0.89147 xc 290.47328 ±0.14791 w 28.15938 ±0.31185 A 12693.23319 ±133.37826

• Exp. points

Gauss fit

Intensity / 180 s

Channel number

200 300 400 50 100 150

Channel number

y0 10.59425 ±0.41425 xc 290.28919 ±0.20455 w 28.29931 ±0.43141 A 4293.31844 ±62.13225

• Exp. points

Gauss fit

Intensity / 60 s

200 300 400 10 20 30 40 50 60

Channel number

y0 3.26385 ±0.19322 xc 290.70484 ±0.28109 w 28.1952 ±0.5927 A 1450.1081 ±28.92698

• Exp. points

Gauss fit

Intensity / 20 s

200 300 400 5 10 15

Channel number

y0 0.84227 ±0.09552 xc 288.05412 ±0.54286 w 28.47831 ±1.14544 A 376.16193 ±14.37198

• Exp. points

Gauss fit

Intensity / 5 s

Diffraction peaks of α-Fe(211) for different measurement times 180 s 60 s 20 s 5 s

α-Fe-pin, Φ=2 mm

• 1. P. Mikula, M. Vrána, V. Wagner, M. Furusaka, Nucl. Instrum. Methods in Phys. Research,

Section A, A586 (2008) 18-22.

• 2. P. Mikula, M. Vrána, and V. Wagner , Chapter in the book “Modern Developments in X-ray and

Neutron Optics”, eds. A. Erko, M. Idir, T. Krist, A.G. Michette, Springer Berlin/Heidelberg, Volume 137/2008, pp. 459-470.

• 3. R.C. Wimpory, P. Mikula, J. Šaroun, T. Poeste, Junghong Li, M. Hoffmann and R. Schneider,

Efficiency Boost of the Materials Science Diffractometer E3 at BENSC: One Order of Magnitude, Due to a Double Focusing Monochromator, Neutron News, 19 (2008) 16-19.

• 4. R.C. Wimpory, P. Mikula, J. Šaroun, T. Poeste, R. Schneider, J. Li and M. Hoffmann, Efficiency

Boost of the Materials Science Diffractometer E3 at BENSC: One Order of Magnitude, BENSC Experimental Report 2007, HMI Berlin, Edited by U. Stahnke, A. Brandt and H.A. Graf, April 2008, HMI-B 617, ISSN 0936-0891.

• 5. M. Furusaka, K. Kamada, Y. Kiyanagi, F. Fumiyuki, A. Homma, K. Ikeda, K. Hirota, H.

Shimizu, S. Satoh, P. Mikula, T. Satoh, K. Tanabe, K. Koyama, H. Takahashi, K. Fujita, T. Kamiyama, S. Naito, Y. Kawamura, H. Yoshizawa, S. Ikeda, First results from a mini-focusing Small-Angle Neutron Scattering Instrument (mfSANS) with an ellipsoidal mirror, In Proc. of the

• Int. Conf. On Advanced Neutron Sources ICANS XVIII, April 26-29,2007, Dongguan, China.
• 6. M. Furusaka, T. Satoh, Y. Sasaki, Y. Kawamura, T. Asami, Y. Otake, K. Ikeda, P. Mikula, Y.

Kiyanagi, S. Naito, H. Yoshizawa, Installation of a prototype of focusing-type small-angle neutron scattering instrument with an ellipsoidal supermirror, Activity Report on Neutron Scattering Research: Experimental Reports 15 (2008), Report Number: 655, Tokyo University

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