Small Angle X-ray Scattering (SAXS) Measurements

Small Angle X-ray Scattering (SAXS) Measurements
1. Start up the X-ray generator, elapsed time of 30 to 60 min is usually
required to stabilize the focal position of the X-ray tube.
2. It is presumed that the instrument has been aligned for parallel beam
geometry with standard stage already.
3. Inside Rigaku Control Panel:
Go in the RINT2200 and change following:
� In system construction (See Below)
a. Attachment-Sample Holder (transmission method)
b. Slit- SAXS slit
c. If monochromator choice: No Monochromator
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� In geometry of the system (Figure 7)
a. Small Angle
4. On the goniometer put standard sample holder, remove diffracted beam
monochromator and start automatic alignment. During the alignment you
will be asked to put the SAXS sample holder. SAXS slit and other
attachments.
5. Components that you will be asked to put are
SAXS selection slit in place of PB slit
Vacuum Path
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SAXS Unit
6. Always put the sample in a way that sample surface faces the detector
side.
7. For collecting SAXS data, run a 2theta scan. A representative scan
condition is described in Table 1 below.
8. For analyzing SAXS data with NANO-Solver, a ratio of intensities (R) with
and without sample is required, i.e.
R = (Intensity with sample placed in sample holder using count
monitor/Intensity without sample placed in sample holder using count
monitor). Good values of R are between 1/3 to ½ (30-50%).
a. If lower try slicing thinner sample or use reflection SAXS
b. If too high, add a layer to sample to increase X-ray absorbance
Theta-D = 0
Collect raw counts in theta/2theta mode with count monitor window and
setting Theta-d and Theta-s at 0 degrees (0 degree for both arms by
driving Theta-d and theta-s to zero) and using a Al absorber as attenuator
in Manual Mode (see below), Make sure for all the runs the DS, RS and
SS have same value.
Now choose control axis as theta/2theta and using count monitor, press
execute button. Note the counts both with and without the sample to get R.
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Table 1.
Instrument Configuration and Scan Parameters for Small Angle Scattering
measurements (SAXS)
Optics: Cross Beam Optic (CBO) with Parallel beam
Sample Preparation : use the ground powder from previous measurements and
sandwich approximately 3mg of sample between two layers of 0.0001” thick mylar film
(from Chemplex). Screw the sample into the transmission holder and place in the beam
path. Background measurements were also taken of just the two layers mylar film.
For SAXS
Slits: Selection Slit: 0.03 mm
Divergence Slit: 1mm
Scatter Slit: 0.2 mm
Receiving Slit: 0.1 mm
Install Vacuum path boxes (2)
Filter: No filter needed, no monochromator
Detector: Scintillation Counter NaI (Tl)
Scan Range: 0.1º to 8.0º 2�
Scan Type: 2� only , fixed slit mode, chose a fixed 2theta = 1.5 degree
Step Size: 0.01º2�
Scan Speed: 10second dwell time FT (total time 98minutes)
Run 2theta scans
To measure background without sample use Al absorber as attenuator
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Figure 1. SAXS Transmission holder with sample sand witched in mylar film
Figure 2. Various selection slits. Use 0.03 mm slit for SAXS measurement.
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