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Small Angle Neutron Spectrometer covers the low scattering
angle(<10 ) and probes inhomogeneities(defects, pores,
precipitates, nano sized microstructure) on the length
scale of a few to several hundred nanometers in materials.
HANARO SANS was opened to users since July 2001.
HANARO Neutron Four Circle Diffactometer(FCD)
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Design Characteristics
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γ/n Filter : LN2
cooled Bi/Be filter
Monochromator
: Neutron Velocity Selector with
variable speed
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wavelength range : 0.4nm ~ 0.8nm
-
/ (FWHM) : 10%
Collimator
: Pin
hole type
Detector : 2D-PSD(3He),
65x65cm2 with 5mm2 resolution
Sample
Size : 5
∼ 20mm diameter
Q-range : 0.06
to 8nm-1
| Calculated Flux at sample : |
Qmin(nm-1) |
Is(n/sec) |
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0.06 |
2 x 103 |
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0.1 |
3 x 104 |
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1.0 |
3 x 105 |
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HANARO SANS was installed at CN beam
port in reactor hall. A liquid-nitrogen
cooled
aluminum cryostat containing 20
cm of single-crystal Bi and 20 cm of polycrystalline
Be is used as a gamma-ray and fast-neutron
filter.
The polychromatic beam following
the filter is monochromatized with wavelength
of 4-8 by a neutron velocity selector.
The helically twisted rotor lamellae which
are coated with 10B as absorbing material
is located inside the neutron velocity selector.
The monochromatized neutron beam with specified
wavelength is obtained with varying rotor
rpm.
The two-dimensional 3He-detector
with 128 x 128 elements of 5 x 5 mm2 is
installed in a vacuum chamber and can be
positioned at any distance between 1.5 and
4.5 m from the sample in the horizontal
direction. Additionally, the vacuum chamber
can be tilted by 7.5 and the detector can
be moved horizontally by 294mm. The measuring
q range extended and the detecting efficiency
doubled by the tilting and moving system.
8
stage sample holder, 4 stage heating stage(RT-200
), 4 stage cooling/heating stage(-20 -
80 ) and electromagnet(1.5T) were equipped
as sample environments. Sample exchange,
temperature and data aquisition can be controlled
in PC program. Sequential adjusting measurement
conditions and automatic measurements can
be performed in PC. Solid samples(thickness
of 0.2-2mm and diameter of 10mm-20mm) and
liquid samples(>1cc) can be measured
in SANS.
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Application fields of
SANS
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Analysis of sintering behavior of nano-crystalline
materials
Investigation of nano sized
inhomogeneities in metals and ceramics
Study
of complex liquids such as microemulsions,
colloids and liquid crystals
Investigation
of the structure and morphology of polymer
systems
Structural studies of biological
macromolecules
Precipitate analysis in
high strength and high formability steel/aluminum
for automotive application
Basic study
of NT, BT and IT fields
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Sample environments and major
components
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Speed
range(rpm) : 3000-28300
Wavelength spread(fwhm)
: 10%
Window : aluminum foil
Active
area : 64.5cm x 64.5cm
Spatial rasolution
: 128 x 128 pixels
Pixel size : 0.5cm
x 0.5cm
Counting gas : 77% 3He + 23% CF4 at 260kPa
Neutron
detection efficiency : 80%@5Å
Spartial
uniformity : ±10% differential
Bath
volume : 30L
Temperature range : -10℃
-80℃
Control : P.I.D. control with pt-100Ω
Cooling
capacity : 550kcal/Hr
Air
Gap & Range : 0.165-18.42 cm
Magnetic
field : max 1.5T
Type : Horizontal Variable |
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Publication
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1. The Small Angle Neutron Spectrometer
at the HANARO Reactor, Korea, B. S. Seong
et al., Appl. Phys.
A 74[Suppl.], S201-S203 (2002)
2. Micellar
Aggregation and Structure of Dodecyl Heptaethoxylates
(C12E7) with
Different
Oxyethylene Distributions in Aqueous Media,
J. B. Jeong et al., Langmuir
18,
8749-8755 (2002)
3. Effect of Precipitate
Size and Dispersion on Recrystallization
Behavior in Ti-added
Ultra
Low Carbon Steel, E.J Shin et al., J Appl.
Cryst. 36, 624-628 (2003)
4. Effect of
Hydrostatic Pressure on Closed-Loop Phase
Behavior of Block Copolymers,
D.
Y Ryu et al. Physical Review Letters, 90,
23, 235501 (2003)
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