Recent Advances in Anomalous Small-Angle
X-Ray Scattering from Soft Matter Systems
M. Sztucki, E. Di Cola, T. Narayanan
European Synchrotron Radiation Facility
Beamline ID2
Grenoble, France
Outline
ASAXS at the high brilliance beamline ID2, ESRF
Recent advances in ASAXS instrumentation
Software package for online data reduction
ASAXS at bromine K-edge:
Outlook
C38H80NBr (DODAB),
C14H29N(CH3)3Br (TTAB)
Outline
ASAXS at the high brilliance beamline ID2, ESRF
Recent advances in ASAXS instrumentation
Software package for online data reduction
ASAXS at bromine K-edge:
Outlook
C38H80NBr (DODAB),
C14H29N(CH3)3Br (TTAB)
ASAXS at high brilliance beamline ID2, ESRF
Quantitative ASAXS of charged soft matter systems can deliver unique information
about charged soft matter systems:
• counterion distribution around macroions.
e.g. polyelectrolytes, micelles, vesicles, biological molecules such as DNA, proteins, etc.
• role of counterions in self-assembly, folding, etc.
• stability of interfaces (oil/water emulsions).
• coulomb coupling and fluctuation effects.
Experimental issues:
low concentration of the anomalous species
sample stability
radiation damage
 high demands on instrumental setup as compared to hard materials
 online data reduction essential to assure high quality measurements
 advances in theory and simulations necessary
ASAXS at high brilliance beamline ID2, ESRF
Pinhole SAXS:
Bonse-Hart USAXS:
flux: 1014 ph/s,
qmin = 3x10-3 nm-1
qmin = 8x10-4 nm-1
low divergence: 15 x 38 µrad (high β section)
energy range: 8 - 20 keV, ∆E/E=2 x 10-4,
beam size: 0.06 x 0.45 mm (new optics),
sample-detector distance: 0.8 – 10 m (evacuated flight tube, CCD FreLoN)
Outline
ASAXS at the high brilliance beamline ID2, ESRF
Recent advances in ASAXS instrumentation
Software package for online data reduction
ASAXS at bromine K-edge:
Outlook
C38H80NBr (DODAB),
C14H29N(CH3)3Br (TTAB)
Recent advances in ASAXS instrumentation
X-ray source:
high beam stability
high flux, low divergence (high β section)
Dedicated sample environment:
ASAXS dedicated temperature controlled (in-vacuum) flow-through cell
techniques reducing radiation damage
CCD detector and intensity monitors:
high q resolution
low detection limit
good linearity, high stability
accurate transmission measurement
Recent advances in ASAXS instrumentation
Sample environment for solution ASAXS:
Temperature controlled
(in-vacuum) flow-through
capillary cell

motorized syringe for sample
allows reliable calibration of incident energy and
absolute scattering intensity,
for energy: e.g. RbOH; detector efficiency: H2O, lupolen




optimized to reduce scattering background,
allows reliable background subtraction,
small quantity (from 5 µl)
avoid mica windows (vacuum option)
to avoid radiation damage
 continuous movement of the sample while scanning
energy
 thorough de-gassing of the solution
sink
2mm capillaries for sample (w.t. 10 µm),
intensity and energy calibrated standards
Recent advances in ASAXS instrumentation
Principal SAXS detector:

Fiber optically coupled (1:2) FReLoN (Fast-Readout,
Low-Noise) CCD based on Kodak KAF-4320 image
sensor.

High quantum efficiency. Single photon (12.4 keV)
level comparable to noise floor 2.5 ADU/ph vs. 2 ADU
readout noise.

Nominal dynamic range of 16bit (14 1/2 bit above
the noise floor) and full frame rate of 3 frames/sec
(2048 x 2048).

Active area: 10cm x 10cm

The spatial resolution determined by the point spread
function (PSF) is about 80µm.
New WAXS detector: (under commissioning)
Fiber optically coupled AVIEX, 16 bit, 3584 x 2048 pixel
(pixel size 24µm), active area 5cm x 8.5cm
AVIEX
Recent advances in ASAXS instrumentation
Remotely controlled beamstops with
integrated intensity monitor.
standard beamstop (Rhodium): 2mm x 6mm
(with diode: 1mm x 4mm)
Emphasize on precise study of response
and good linearity of transmission measurement (∆I/I < 0.1%) in the vicinity of relevant
absorption edges.
e.g. Pb L1-edge and Rb K-edge are close
within 2eV
Recent advances in ASAXS instrumentation
Limit of detection:
concentration of counterions
fluorescence above Br K-edge
TTAB 17 mM
-6 eV
water
10
-4
10
-3
10
-4
-1
-3
I(q) [mm ]
10
-1
I(q) [mm ]
water
-6 eV
+8 eV
+8 eV (with fluor.)
TTAB 50 mM
TTAB 17 mM
TTAB 6 mM
1
-1
q [nm ]
1
-1
q [nm ]
Cationic surfactant: Tetradecyl-trimethylamonium bromide C14H29N(CH3)3Br (TTAB)
Outline
ASAXS at the high brilliance beamline ID2, ESRF
Recent advances in ASAXS instrumentation
Software package for online data reduction
ASAXS at bromine K-edge:
Outlook
C38H80NBr (DODAB),
C14H29N(CH3)3Br (TTAB)
Online data reduction
Standard SAXS data reduction:
 SAXSprograms for reduction of two-dimensional small- and
wide-angle X-ray scattering data
P. Boesecke, J. Appl. Cryst. (2007). 40, s423-s427
 Matlab based SAXSutilities
M. Sztucki et al., J. Appl. Cryst. (2007). 40, s459-s462
Integrated software package for ASAXS data reduction:
(energy calibration, normalization for detector response, fluorescence detection and correction, etc.)
Optionally: decomposition in energy independent intensity, cross-term and resonant
scattering due to counterions.
… essential to assure high quality measurements
Online data reduction
ASAXS data reduction:
Integrated MATLAB based software package for automatized energy calibration and
intensity normalization at each energy:
Measurements:
1. Empty background image (verification of transmission)
2. Intensity standard (absolute intensity normalization based on water or lupolen scattering –
depending on sample to detector distance)
(HBr etc.)
3. Energy reference
4. Sample measurement
65
Data reduction:
1. Raw data
2. Normalization to absolute intensity
3. Fluorescence detection and subtraction
4. Background subtraction
transmission [%]
60
55
50
45
40
35
ASAXS at Br K-edge
13400 13420 13440 13460 13480 13500
E [eV]
Online data reduction
Finite energy bandwidth of primary beam
1.5x10
-2
1.4x10
-2
1.3x10
-2
1.2x10
-2
1.1x10
-2
10
-2
9x10
-3
8x10
-3
+50 eV
+6 eV
0 eV
-6 eV
-50 eV
-1000 eV
-1
-2
I(q) [mm ]
I(q)
1.6x10
3.4x10
-3
3.2x10
-3
3x10
-3
2.8x10
-3
2.6x10
-3
2.4x10
-3
2.2x10
-3
2x10
-3
1
2.3x10
-3
2.2x10
-3
2.1x10
-3
2x10
-3
1.9x10
-3
10
-3
10
-4
+50 eV
+6 eV
0 eV
-6 eV
-50 eV
-1000 eV
-1
-1
I(q) [mm ]
fluorescence corrected
-3
+50 eV
+6 eV
0 eV
-6 eV
-50 eV
-1000 eV
-1
q [nm ]
1
1
-1
q [nm ]
-1
q [nm ]
background subtracted
-3
I(q) [mm ]
TTAB, 17mM
q [nm ]
2.4x10
-6 eV
-50 eV
-1000 eV
1
-1
2.5x10
+50 eV
+6 eV
0 eV
normalized
RAW
Online data reduction
-1
I(q) [mm ]
-1
+30 eV
+8 eV
0 eV
-8 eV
-50 eV
-2700 eV
1
q [nm ]
+30 eV
+8 eV
0 eV
-8 eV
-50 eV
-2700 eV
-1
-2
10
-2
3x10
-2
2x10
-2
-1
10
I(q) [mm ]
-1
+30 eV
+8 eV
0 eV
-8 eV
-50 eV
-2700 eV
2
-1
+30 eV
+8 eV
0 eV
-8 eV
-50 eV
-2700 eV
1
-1
q [nm ]
1
-1
q [nm ]
2
1
-1
q [nm ]
2
background subtracted
I(q) [mm ]
1
RbPAMS c=5%
q [nm ]
fluorescence corrected
10
+30 eV
+8 eV
0 eV
-8 eV
-50 eV
-2700 eV
-2
2
-1
I(q) [mm ]
I(q)
10
normalized
RAW
Online data reduction
Online data reduction
SAXS from
spherical particles:
ASAXS from
spherical particles:
4
2
X-ray scattering factor of
a single counterion:
contrast per ion:
Br K-edge
f ', f ''
0
-2
-4
-6
f ''
f'
-8
-10
12000
13474 keV
13000
14000
E [eV]
f ' and f '' from University of Washington Biomolecular Structure Center (http://www.bmsc.washington.edu)
Online data reduction
Decomposition in three components:
1. energy independent normal SAXS,
2. cross term involving the amplitudes of normal SAXS and the resonant scattering of counterions and
3. resonant scattering term due to counterions  spatial distribution
PbPAMS at c=5% w/w
-2
10
2
-1
I(q) [mm ]
F
-3
10
F*v
-4
10
2
v
I
-5
10
1
0.2
2
-1
q [nm ]
integrated in data reduction software
f'
M. Ballauff et al., Coll. Pol. Sc. 284, 1303 (2006)
Flexible highly charged polyelectrolytes in
semidilute regime with Rb as counterion (15.2 keV)
 Poster by E. Di Cola
Outline
ASAXS at the high brilliance beamline ID2, ESRF
Recent advances in ASAXS instrumentation
Software package for online data reduction
ASAXS at bromine K-edge:
Outlook
C38H80NBr (DODAB),
C14H29N(CH3)3Br (TTAB)
ASAXS at bromine K-edge: TTAB
Cationic surfactant:
Tetradecyl-trimethylamonium bromide C14H29N(CH3)3Br (TTAB)
-1000 eV
-60 eV
-10 eV
0 eV
10
-3
10
-4
-1000 eV
-60 eV
-10 eV
0 eV
6 mM
-1
I(q) [mm ]
50 mM
10
-1000 eV
-60 eV
-10 eV
0 eV
17 mM
-5
1
1
-1
q [nm ]
1
-1
q [nm ]
-1
q [nm ]
T.M. Weiss et al., Langmuir 24, 3759 (2008)
ASAXS at bromine K-edge: TTAB
No decomposition algorithm necessary: direct fitting of charge distribution
-1000 eV
2 eV
-1
absolute intensity [mm ]
−2
∆ ρ [ nm ]
1.0x10
-4
0.0
-1.0x10
-1000 eV
2 eV
-4
0
1
2
3
R [nm]
10
 bromide counterions are strongly
condensed on micellar surface
-4
17 mM
0.3
1
-1
q [nm ]
ASAXS at bromine K-edge: DODAB
Dilute aqueus vesicle dispersions of cationic lipid:
Dioctadecyldimethylammonium bromide C38H80NBr (DODAB)
0
10
-1
10
-2
10
-3
10
-4
-1000 eV
-70 eV
-14 eV
-4 eV
0 eV
-1
I(q) [mm ]
10
T=35°C
T=60°C
0.1
1
-1
q [nm ]
-1000 eV
-70 eV
-14 eV
-4 eV
0 eV
-1000 eV
-70 eV
-14 eV
-4 eV
0 eV
T=12°C
0.1
1
0.1
-1
60°C
q [nm ]
1
-1
12°C
q [nm ]
lipid chain freezing
P. Saveyn et al., Soft Matter 5, 1735 (2009)
Outline
ASAXS at the high brilliance beamline ID2, ESRF
Recent advances in ASAXS instrumentation
Software package for online data reduction
ASAXS at bromine K-edge:
Outlook
C38H80NBr (DODAB),
C14H29N(CH3)3Br (TTAB)
The future of ASAXS within the ESRF upgrade program
UPBL9 Brainstorming Meeting
(15-16 December 2008)
recommendations:
+ time-resolved ASAXS in the q-range of light scattering,
+ theoretical modeling
+ ...
Outlook
UPBL9:
(a) Sub-microradian angular resolution
small angle scattering for probing
the structure and non-equilibrium
dynamics of self-assembling soft
matter and biological systems
(b) Structural dynamics of molecular
assemblies
ID02
UPBL9a
Summary
Quantitative ASAXS of charged soft matter systems can deliver unique
information about the spatial distribution of the counterions – even at low
concentration of the anomalous species.
High demands on instrumental setup:
 ESRF, ID2:
 recent advances in ASAXS instrumentation and
(high stability and good linearity of CCD detector and intensity monitors, low detection limit,
dedicated sample environment)

integrated software package for online data reduction,
(energy calibration, normalization for detector response, fluorescence correction, etc.)

optionally: decomposition in energy independent intensity, cross-term and
resonant scattering due to counterions.
ASAXS at bromine K-edge: C38H80NBr (DODAB), C14H29N(CH3)3Br (TTAB)
direct fitting of charge distribution: bromide counterions are strongly condensed on
micellar surface (TTAB).
Acknowledgements
J. Gorini (beamline engineer ID2)
P. van Vaerenbergh (engineer, ESRF)
all present and former ID2 staff (P. Bösecke, P. Panine,
E. Di Cola,
T. Narayanan)
ESRF support groups (Instrument Support Group)
ESRF for beamtime and financial support