SUB-MICRON DIFFRACTION BEAMLINE AT SOLEIL
(SYNCHROTRON LAUE µ-DIFFRACTION)
“AVANT PROJET SOMMAIRE” (APS) FOR SOLEIL
PREPARED BY P. GOUDEAU & O. THOMAS, coordinators
AND THE FOLLOWING CONTRIBUTORS (see appendix 1):
R. BISARO, A. BOSSEBOEUF, F. BRIKI, A. BULÉON, O. CASTELNAU, A.
DEVOUARD, E. DOORYHÉE, J.-L. LEBRUN, G. ROLLAND, O. SICARDY,
RESPONSIBLES FOR SCIENTIFIC FIELDS,
T. MORENO, M. IDIR, RESPONSIBLES FOR INTRUMENT DESIGN
This document is the result of a workshop “Microdiffraction: mécanique des
matériaux et indentification de phases” organized by Soleil and the AFC (French association
for crystallography) at the end of June 2004 (see http://www.synchrotron-soleil.fr) and
followed by three meetings between coordinators and contributors in January, March and
July 2005.
SUMMARY
Beam line specifications
p.2
1. INTRODUCTION
p.3
2. SCIENTIFIC CASES
p.7
3. PROPOSED BEAMLINE AND OPTICS
p.46
Appendix
p.57
2
SUMMARY OF BEAM LINE SPECIFICATIONS
Source
Bending magnet or Wiggler100
Energy range
5-30 keV
Energy modes
Optics
White beam , monochromatic (beam at the same
position on the sample)
Toroïdal mirror for imaging the source, 4-crytals
monochromator and KB focusing
WHITE BEAM (1 - 0.3 µm):
3.71×1013 - 3.46×1012
Bending magnet: 3.03×1012 - 2.10×1011
Integrated intensity (Ph / s) Wiggler:
and Beam size (FWHM) on
the sample
Detection (2D)
MONOCHROMATIC BEAM (8 keV and 0.3 µm):
Wiggler:
1.20×108
Bending magnet: 1.85×107
CCD camera with fast read out and, high spatial
resolution (100 µm) and dynamic (16 bits)
4 circles goniometer with 10 µm sphere of confusion
x-y sample stage (piezo).
Sample environment
Optical microscope for rough sample positioning
Fluorescence
detection
for
accurate
sample
positioning and qualitative measurements.
Furnace and tensile testing set up
Software – data treatment
Cluster (48 nodes)
XMAS (ALS_Tamura) for WB and MB modes
Phase
structure
identification
and
mapping,
microelectronic,
mechanic,
Mechanical stress mapping,
Scientific purpose &
grain orientation mapping
Applications
3D structural microscopy
Materials
sciences:
environment, cultural heritage, earth science …
3
1. INTRODUCTION
Micro-focused x-ray beams from 1 down to less than 0.1 micron in size have
been one of the real success stories of 3rd generation synchrotron x-ray machines
(SR) such as the European Synchrotron Radiation Facility (ESRF), Synchrotron
Photon ring 8 (Spring8), Advanced Photon Source (APS) and Advanced Light Source
(ALS), thanks to a large panel of focusing devices for hard and soft x-rays [1-5].
There is clearly a rapidly growing need for very small x-ray beams – 10 nm is
theoretically possible [6] - which allow for non-destructive local scale measurements
of structure and chemistry. This need of analysis tools combining spatial resolution
with elemental and chemical identification at the nanometer scale encompasses
many different scientific fields: Microelectronics and microsystems, Metallurgy and
mechanics, Environmental and earth sciences, Art and archaeology, Life sciences
and soft condensed matter. In all these different research fields one would ideally like
to get information on a local scale of the structure, the chemical composition and the
local atomic environment. This implies performing at the submicron scale: X-ray
diffraction (XRD), X-ray fluorescence (XRF), EXAFS, XANES.
However, the case of XRD technique is specific in the sense that the recorded
signal does not only depend on the beam size but also on the ratio of the beam size
to the grain size. If this ratio is large enough one is left with powder diffraction when
using monochromatic x-ray beam (MB) and the diffraction information is an average
over the size of the beam. On the other hand if the beam size over grain size ratio is
small one gets single crystals diffraction. It is thus possible to obtain intragrain
structural information. High pressure experiments in transmission configuration with
hard x-rays use either MB [7] or white beam (WB) [8] XRD with generally energy
dispersive mode. This last mode is also used for stress measurements in materials
engineering [9].
For the proposed beam line, the working geometry is reflection. It is important to
realize, however, that recording a significant number of diffraction spots from a single
crystal requires either a movement of the sample under the beam (goniometry) or the
use of a polychromatic incoming beam (Laue diffraction) combined with a twodimensional area detector such as CCD type. Since there are no available
goniometers with a sphere of confusion (SOC) radius smaller than the micrometer xray probe size it is thus necessary to use WB. These different configurations related
to the x-ray spot size over grain size ratio are given in fig. 1 and details concerning
the different applications of the technique may be found for instance at the Advanced
Light Source (ALS) web site address (http://xraysweb.lbl.gov/microdif/index.htm).
This synchrotron source has been taken as an example because Soleil and ALS
source characteristics are close enough compared for instance with those of the
Advanced Photon Source (APS) hard x-ray source, an other synchrotron radiation
4
facility where white beam µXRD is commonly used. Furthermore, several contributors
to this project have been involved with micro scanning XRD (µSXRD) experiments at
the ALS. A French CNRS post-doc is presently working at the ALS in the framework
of a collaboration between two French laboratories (TECSEN – Marseille and LMP –
Poitiers) and the Experimental System Group at ALS-LBNL which provides additional
financial support and working place. The main project presented at CNRS is given in
appendix 2. One of the objectives is to realize 3D analysis based on APS
instrumental methodology [10 - 12] and ALS software treatment [13 - 15]. (See
publication list in appendix 3)
Figure 1. Principle
for white and mono
chromatic x-ray
beam experiment
according to the
crystallite sizes. In
both cases, no
sample rotations are
required except for
texture and
structure
refinements in case
of MB and WB
respectively.
A last remark concerns the choice between either WB or MB. In fact, both must
be available on the beam line since WB may be used for calibration in a MB
experiment (nanocrystalline thin film deposited on a single crystal wafer) and also
when the material to be analyzed contains nano and micro grains even of the same
phase (case of a gold film made of <111> oriented micro grains and random nano
grains). In this last case, both families of grains may be analysed separately by using
either WB (larger grains) or MB (smaller grains) [10]. Finally, WB may be used in
fluorescence mapping experiments for qualitative measurements and x-y sample
stage calibration. This is essential for locating precisely the zone where XRD
scanning has to be done, a coarse approach being perfomed through the use of an
optical camera with a 100 µm resolution.
Figure 2 shows the existing microbeam lines in the world and those planned for
the near future. There is almost nothing in Europe in terms of fully dedicated WB
µXRD beam line except the BM32 project at ESRF (10 % of the full beam line time
dedicated to microfocus WB during 3 years) and a planned White beam line at
5
Candle in Armenia. It appears then crucial for the European community to build such
an experimental facility since the scientific cases developed in the following
paragraphs for the French community equally hold for the other European
communities. A European Workshop concerning specifically Synchrotron Laue
Diffraction could be organized at Soleil (pioneering SR facility in Europe for that
purpose) next year.
Figure 2. Inventory of microfocus x-ray beam lines all over the word for the present
and the near future (from N. Tamura, Workshop “Microdiffraction: mécanique des
matériaux et identification de phase”, June 2004, Orsay (France))
6
REFERENCES
___________________________________________________________________________
[1] F. Pfeiffer, C. David, M. Burghammer, C. Rieckel, T. Salditt, Two dimensional X-ray
waveguides and point sources, Science 297, 230 (2002).
[2] O. Hignette, P. Cloetens, G. Rostaing, P. Bernard, C. Morawe, Efficient sub 100 nm
focusing hard x-rays, Review of Scientific Instruments 76, 063709 (2005).
[3] C. G. Schroer, B. Lengeler, Focusing hard x-rays to nanometer dimensions by
adiabatically focusing lenses, Physical Review Letters 94, 054802 (2005).
[4] W. Chao, B.D. Hartenaeck, J.A. Liddle, E.H. Anderson, D.T. Attwood, Soft x-ray
microscopy at a resolution better than 15 nm, Nature 435, 1210 (2005).
[5] C. G. Schroer, O. Kurapova, J. Patommel, P. Boye, J. Feldkamp, B. Lengeler, M.
Burghammer, C. Rieckel, L. Vincze, A. van der Hart, M. Küchler, Hard nanoprobe based on
refractive x-ray lenses, Applied Physics Letters 87, 124103 (2005).
[6] C. Bergemann, H. Keymeulen, J. F. van der Veen, Focusing x-rays beams to nanometer
dimensions, Physical Review Letters 91, 204801 (2003).
[7] M. Mezouar, W.A. Crichton, S. Bauchau, F. Thurel, H. Witsh, F. Torrecillas, G.
Blattmann, P. Marion, Y. Dabin, J. Chavanne, O. Hignette, C. Morawe, C. Borel,
Development of a new state of the art beamline optimized for monochromatic single-crystal
and powder x-ray diffraction under extreme conditions at the ESRF, J. of Synchrotron Rad.
12, 659 (2005).
[8] G. E. Ice, P. Dera, W. Liu, H.-K. Mao, Adapting polychromatic x-ray microdiffraction
techniques to high-pressure research: energy scan approach, Journal of Synchrotron
Radiation 12, 608 (2005).
[9] A. M. Korsunsky, S. P. Collins, R. A. Owen, M. R. Daymond, S. Achtioui, K. E. James,
Fast residual stress mapping using energy dispersive synchrotron X-ray diffraction on station
16.3 at the SRS, J. Synchrotron Rad. 9, 77 (2002).
[10] B. C. Larson, W. Yang, G. E. Ice, J. D. Budai, J. Z. Tischler, Three-dimensional X-ray
structural microscopy with submicrometre resolution, Nature 415, 887 (2002) |
[11] G. E. Ice and B. C. Larson, Three-Dimensional X-Ray Structural Microscopy Using
Polychromatic Microbeams, in “High-Resolution Three-Dimensional X-Ray Microscopy, B.
C. Larson and B. Lengeler, Guest Editors, MRS Bulletin 29, 170 (2004).
[12] W. Liua, G. E. Ice, B. C. Larson, W. Yang, J. Z. Tischler, Nondestructive threedimensional characterization of grain boundaries by X-ray crystal microscopy,
Ultramicroscopy 103, 199 (2005).
[13] J. S. Chung, G. E. Ice, Automated indexing for texture and strain measurements with
broad-bandpass x-ray microbeams, J. Appl. Phys. 86, 5249 (1998).
[14] N. Tamura, J. – S. Chung, G. E. Ice, B. C. Larson, J. D. Budai, J. Z. Tischler, M. Yoon,
E. L. Williams, W. P. Lowe, Strain and texture in Al-interconnect wires measured by X-ray
microbeam diffraction, Mat. Res. Soc. Symp. Proc. 563, 175 (1999).
[15] N. Tamura, R. S. Celestre, A. A. MacDowell, H. A. Padmore, R. Spolenak, B. C. Valek,
N. Meier Chang, A. Manceau, J. R. Patel, Submicron x-ray diffraction and its applications to
problems in materials and environmental science, Review of Scientific Instruments 73, 1369
(2002)
7
2. SCIENTIFIC CASE
In the following, the fast growing need for micro-focused x-ray diffraction is
evidenced and developed through selected examples which belong to different
scientific fields already mentioned in the introduction. Recent achievements as well
as future prospects are given. For each scientific field, the following items have been
adressed: 1) State of the art: major challenges arising from local scale analysis,
prospects in downscaling from micro towards nano XRD [1 - 3]), technical breaking
points. 2) National and international scientific background. 3) Scientific communities
involved: scientific societies, laboratories, applications and industrial / civil society
links (potential financial supports). Two “Circles of Interest” have been distinguished
according to whether WB applications are crucial or just complementary. Although
the latter criterion does not represent a scale of scientific value, the aim here is to
emphasize what is not presently achievable in France and more widely in Europe in
material sciences with XRD due to the lack of a microfocused white beam diffraction
set-up. The emphasis has thus been clearly put in section 2A on materials for
microelectronics, metallurgy and mechanics. Other materials of interest for emergent
scientific fields and industries, currently used for buildings, transportation and other
public facilities and consequently named “materials of broad use”, are not explored in
that memory. It is obvious that micro XRD has important applications for full
characterization of these materials i.e. concretes, glasses, nanotubes,
composites…This powerful analysis tool will complement advantageously emergent
analysis techniques either developed for fast phase transformation studies [4], strain
measurements in amorphous phases [5, 6] or using coherence property of
synchrotron radiation beam [7-9] and the anomalous effect [10].
8
REFERENCES
_______________________________________________________________________________________________________________
[1] S. Lagomarsino, S. Di Fonzo, W. Jark, G. Giannini, L. De Caro, A. Cedola, X-ray nano
diffraction : 100 nm resolution obtained in a novel imaging technique for strain measurement
at buried inerfaces, Microelec. Engineering 53, 645 (2000).
[2]S. Di Fonzo, W. Jark, S. Lagomarsino, C. Giannini, L. De Caro, A. Cedola, M. Müller,
Non-destructive determination of local strain with 100-nanometre spatial resolution, Nature
403, 638 (2000)
[3] Y. Xiao, Z. Cai, Z. L. Wang, B. Lai, Y. S. Chu, An X-ray nanodiffraction technique for
structural characterization of individual nanomaterials, J. Synchrotron Rad. 12, 124 (2005).
[4] D.H. Kalantar, J.F. Belak, G. W. Collins, J. D. Colvin, H. M. Davies, J. H. Eggert, T. C.
Germann, J. Hawreliak, B. L. Holian, K. Kadau, P.S. Lomdahl, H. E. Lorenzana, M. A.
Meyers, K. Rosolankova, M. S. Schneider, J. Sheppard, J. S. Stölken, J. S. Wark, Direct
observation of the α - ε transition in shock-compressed iron via nanosecond x-ray diffraction,
Physical Review Letters 95, 075502 (2005).
[5] G. Ice, Characterizing amorphous strain, Nature Mater. 4, 17 (2005).
[6] Poulsen, H. F., Wert, J. A., Neuefeind, J., Honkimaki, V., Daymond, M., Measuring strain
distribution in amorphous materials, Nature Mater. 4, 33 (2005).
[7] J. Miao, T. Ishikawa, B. Johnson, E. H. Anderson, B. Lai, K. O. Hodgon, High resolution
3D X-ray diffraction microscopy, Physical Review Letters 89, 088303 (2002).
[8] I. K. Robinson, J. Miao, Three-Dimensional Coherent X-Ray Diffraction Microscopy, in
“High-Resolution Three-Dimensional X-Ray Microscopy, B. C. Larson and B. Lengeler,
Guest Editors, MRS Bulletin 29, 177 (2004).
[9] I. A. Vartanyants, I. K. Robinson, J. D. Onken, M. A. Pfeifer, G. J. Williams, F. Pfeiffer,
H. Metzger, Z. Zhong, G. Bauer, Coherent x-ray diffraction from quantum dots, Physical
Review B 71, 245302 (2005).
[10] A. Letoublon, V. Favre-Nicolin, H. Renevier, M.G. Proietti, Monat, M. Gendry, O.
Marty, C. Priester, Strain, Size, and Composition of InAs Quantum Sticks Embedded in InP
Determined via Grazing Incidence X-Ray Anomalous Diffraction, Physical Review B 18,
186101 (2004).
9
2.A. 1ST CIRCLE: PRIORITY FOR WHITE BEAM MICRODIFFRACTION
Microelectronics / Microsystems
The last 40 years have seen a fantastic exponential increase of the density of
transistors one can write on a given silicon area. This was made possible thanks to the
development of micro-technologies. These technologies have spread out of the “classical”
micro-electronics area towards all sorts of different fields where one wants to fabricate
devices (motors and actuators, pipes …) at a scale as small as possible. Nowadays technology
fields such as MEMS (Micro ElectroMechanical Systems) or Microfluidics are well
recognized areas for Research and Developments (R&D). Micro and nano-technologies are
characterized by the assembling at a small scale of different functional materials (metals,
semi-conductors, dielectrics, …) with vastly different thermal and mechanical properties
(figure 1). Hence, the issue of mechanical stresses in nano- and micro-technologies has been
considered very early as a major one. With the decrease in the size of the elemental features it
has become critical and calls for the evaluation of the stress tensor at a submicrometer scale.
In France a national research network “STRESSNET” (www.stressnet.org) is specifically
aimed at addressing mechanical stresses in nanotechnologies. STRESSNET represents a very
large community which spans from academic laboratories (many CNRS-Universities
laboratories such as IEF, LMP, TECSEN, CEMES, … and also CEA laboratories such as
DRT/LETI, DRT/LITEN, DSM/DRFMC) to industrial ones (STMicroelectronics, Philips,
FreeScale, THALES, ATMEL, SoiTech, …) . As detailed below, mechanics of small
dimension materials is of concern both for fundamental research and industries.
Very high stresses arise in thin films and in the nanopatterned structures (lines, dots)
which are made from them due to the constraint of the substrate to which they are attached.
The origins and magnitudes of these stresses are of great interest in technology since many
fabrication and reliability problems are stress related. Fundamental interest arises because the
mechanical behaviour of these small structures can significantly deviate from scaling laws
developed for bulk materials. In most experimental and modelling programs, the average
stresses in thin films or nanopatterned structures are studied. However, recent evidence from
microdiffraction experiments performed at ALS [1-4] shows that the stress within such
structures can be enormous, suggesting that an understanding of the stress distributions in
such objects is necessary in order to understand their mechanical behaviour. Inhomogeneous
stress states arise in thin films and nanopatterned structures from effects operating at three
different length scales. At the length scale of the object itself, they arise because of the way
loads are transferred to it from its surroundings. At the length scale of the grains or phases
which build up the object they arise due to the requirements that stress fields be continuous
and displacement fields be compatible. Within an individual grain or phase, they arise due to
variations in the microstructure that controls plastic deformation.
One of the most common sources of stress in thin films and nanopatterned structures is
differential thermal expansion. The differential thermal strain between a film and substrate for
a change in temperature from To to T can be written as εth = (αs - αf)(T - To) where αs and αf
are the thermal expansion coefficients of the substrate and film, respectively. Virtually all of
the differential thermal strain is accommodated by the film if it is thin relative to the substrate.
For an isotropic, homogeneous film, the stress state is one of constant equal biaxial stress [5,
6] away from the edges. The components of the stress tensor acting on the free edges of the
film are zero. Shear stresses arise along the interface near the edges of the film and transfer
load to the film, generating an in-plane normal stress that rises to a constant value away from
the edge. A small normal component perpendicular to the interface also appears near the
edge.
10
bridge
(A)
ring
Micro resonator
Shape Memory
Alloy Micro
actuators
Si (B) bridge
cantilever
(B)
P0
P0P1
P0O1P1
P0P1P2
PoO1P1O2P2
P0P1O2P2 P0P1P2M
P0P1M
P0M
Au
M
(C)
Si
SEM
Optical microscopy
0.75µm
2µm
0.52µm
1.5µm
2µm
0.5µm
0.6µm
Figure 1. Role of mechanical stresses in MEMS devices. In the case of shape memory alloy
thin films (A), deformation due to thin film residual stresses occurs after removing the silicon
substrates for cantilevers, bridges and rings structures. Boron doped Si Micro resonators (B)
are very sensitive to residuals stresses [7]; when the bridge breaks at one end, a stress
relaxation may provide such strange feature (blue arrow). These two first examples are
coming from IEF Orsay (France) studies while the last is related to micro mechanical
characterisation at CNES Toulouse (France). The visible deflection of the cantilever (C) is
due to intrinsic stresses in the gold film. For examples (B) and (C), micro scanning X-ray
diffraction expriments have been done using white and monochromatic beams [8, 9].
11
The extent to which the stress state is inhomogeneous due to this geometric edge effect
depends on the size of the object. For typical systems, edge effects are confined to within a
few film thicknesses from the edge. For a blanket film on a substrate where both are made of
isotropic, homogeneous materials, the stress state in the film is one of uniform equal-biaxial
stress (in plane stresses σxx = σyy, all other stresses are equal to zero) everywhere except for a
region within a few film thicknesses of the edge. For lines and dots where the in-plane
dimensions are comparable to the thickness, the stress state can be quite inhomogeneous (Fig.
2).
Although blanket films are usually treated as if they were isotropic and homogeneous, this is
usually not the case. Thin metallizations are typically polycrystalline with columnar grain
structures (all grain boundaries perpendicular to the film surface). Such films typically
develop strong but mixed textures. For example, the most common orientations in
polycrystalline films made of face centred cubic (fcc) materials are those with (111) and (100)
planes parallel to the plane of the film. These two orientations minimize interface and strain
energy, respectively, and are the stiffest and most compliant, respectively. For example, in
Cu, the biaxial elastic moduli (ratio of equal biaxial stress to equal biaxial strain) for these
orientations at room temperature are Y111 = 261 and Y100 = 115 GPa. Since the thermal
expansion coefficients are isotropic, the differential thermal strain is uniform. The stress state,
however, is not, as shown in Figure 3a.
12
Fig. 3. In-plane normal strains (solid lines) and stresses (dashed lines) in (111) and (100) oriented grains in an
fcc film with thickness h and in-plane grain size d. a) For large d/h, the stresses will be higher in the stiffer (111)
grain away from the boundary. At the grain boundary, stress continuity requires that strain gradients exist. b)
For small d/h, uniform stress is possible along the midline of the film. From [11].
Here, a schematic of a grain boundary between (111) and (100) grains in a passivated Cu
film on a substrate is shown. If the sample deforms only elastically, then far from the
boundary, the stress in each grain will just be that given by the differential thermal strain and
Hooke’s law, σhkl = εthYhkl, so that σ111/σ100 = Y111/Y100 = 2.3. However, the stress field must
be continuous across the grain boundary. This can be accomplished, at least in the middle of
the thickness of the film, if the grain boundary bows out elastically so as to increase the strain
in the more compliant (100) grain and decrease the strain in the stiffer (111) grain, resulting
in a stress gradient near the boundary as shown. Shear stresses arise near the grain
boundary/interface triple junction unless the film slides locally along the interface to relieve
them. If we again assume that most of the stress difference will be accommodated within a
few film thicknesses of the boundary, then we can imagine a range of stress states depending
on the grain size, d. If d is very much larger than the film thickness, h, then the elastic strain
will be uniform everywhere (isostrain) except near the grain boundary and the ratio of the
stresses in the two orientations will be approximately σ111/σ100 = 2.3 (Fig 3a). On the other
hand, for sufficiently small grains (d << h) as illustrated in Fig. 3b, nearly complete stress
accommodation is possible and the in plane normal stress will approach uniformity in the
middle of the film (isostress) with large shear stresses near the interfaces.
Stress distributions may arise within individual grains as well if the microstructure that
controls deformation is inhomogeneous. In brief, stress distributions and mechanical
deformation are inhomogeneous in most engineering materials, Stress heterogeneities,
however, have very different effects in bulk materials and nanoscale structures. In bulk
materials, the individual deforming units are typically orders of magnitude smaller than the
size of the object. Domains with high stresses or stress gradients are averaged together with
regions having low stresses and stress gradients to obtain the composite behaviour. Large
deformations or even fracture in some domains does not necessarily imply large deformations
or fracture of the entire object. In contrast, in a thin film or nanostructure, the individual
deforming units are often of the order of the size of the object. High stresses or stress
gradients within one of these domains is equivalent to high stresses or gradients across the
entire object and large deformations or fracture within a domain is equivalent to large
deformations or fracture of the component. Thus, the stress concentrations that exist due to
13
local heterogeneities may lead to failure of the component. Furthermore, as suggested in Fig.
2, the distances over which stress gradients are accommodated depend on aspect ratio, not
absolute dimensions. Thus, as dimensions decrease, the magnitude of stress gradients
increases. Understanding stress distributions in such nanoscale objects is as important,
and indeed may even be more important than understanding the mean stresses.
The stresses in thin films and patterned structures are typically investigated
experimentally using deflection measurements or x-ray measurements, which invariably
provide a measure of average stresses on some scale. Perhaps the most common is the
substrate curvature method, where changes in the curvature of a substrate induced by stress
interactions with an attached film are measured. Changes in stress can then be calculated from
the measured changes in curvature. This method returns a global average of all the
σRSS (MPa)
Angle (°)
50
45
40
Y (µm)
35
30
25
20
15
35
30
25
20
15
300.0
270.0
240.0
210.0
180.0
150.0
120.0
90.00
60.00
30.00
0
40
35
30
25
Y (µm)
55
55.00
49.50
44.00
38.50
33.00
27.50
22.00
16.50
11.00
5.500
0
40
Y (µm)
3500
3150
2800
2450
2100
1750
1400
1050
700.0
350.0
0
60
20
15
10
10
5
5
10
5
0
0
0
55
60
X (µm)
46 48
48
X (µm)
X (µm)
(b)
(c)
constituents in the film.
(a)
Figure 4: Analysis of a 3 µm wide copper line with µSXRD [12] at ALS – LBNL Berkeley
(USA): Since failure in interconnects have micro structural origin (such as local stress
concentration), local stress distribution along the line as well as grain orientation is
investigated. First, we performed a Cu fluorescence map to precisely locate the X-ray micro
beam position with respect to the sample surface and calibrate the x-y stage [figure 1 (a)]. In
the case of electrodeposited Cu in damascene line, the grain size is larger than the X-ray spot
size (1 µm2). Our results show that despite the fact that conventional X-ray diffraction
measurements have shown that (111) fibre texture is predominant, large grain with (100)
orientation such as the red one [figure 1 (b)] occasionally occur in individual lines.
Deviatoric stress tensor determination with the XMAS software allows for the calculation of
the resolved shear stress. By switching to monochromatic beam, we can additionally measure
the energy of one Laue spot to get the dilatation component of the strain tensor and thus
14
added to the deviatoric component, the total strain tensor. Stress is low except in a few
localized areas where it reaches high values of up to 600 MPa [figure 1 (c)].
X-ray diffraction can be used to measure strains in more specific regions of a sample and
may be divided into two general classes. In a broad beam experiment, a large area (relative to
the size of the individual deforming components) of the sample is illuminated. By use of a
sufficiently monochromatic collimated beam, diffraction peaks from domains of a particular
phase and orientation can be examined separately. The advantage of this method is that the
average strains for a particular type of domain (e.g. orientation or phase) can be determined
with very high precision. The disadvantage is that the strain distribution within an individual
domain cannot be directly measured. In contrast, in a microdiffraction experiment, a very
small x-ray beam is used to illuminate a small volume of material. To the extent that the beam
size is small compared to the domain size, the strain distribution within that domain can be
measured (see fig. 4).
Stress heterogeneities are particularly important in determining the reliability of lines and
dots. Here stress concentrations, gradients, or shear stresses that span the object can lead to
failure by void formation, electromigration or delamination (fig. 5). Stress gradients that lead
to void formation, for example, will lead to failure of a conductor line when the void spans
the line. For this reason, there is a great deal of technological interest in controlling the stress
distributions in these structures (e.g. [13]). Even stress distributions due to simple edge effects
as shown in Fig. 2 are currently of tremendous interest in the microelectronics industry since
traditional SiO2 dielectrics are scheduled to be replaced with “low k” dielectrics, generally
made of polymers and/or porous materials which are extremely compliant. Use of these
materials will lead to much higher stress gradients and interfacial shear stresses in device
metallizations.
Si
Tungsten
σ (MPa)
σ (MPa)
Figure 5: Spontaneous thin film
delamination induced by compressive
residual stresses. The stress varies
continuously from the maximum of
compression in adherent regions to a
value close to zero at the top of the
blister (or buckling). In order to validate
numerical simulations derived from
fracture mechanics and thin plate
theories commonly used to describe such
phenomena, instrumental data are
necessary. For the first time, it has been
done in the case of metallic thin films
deposited on (100) silicon substrates
using monochromatic micro scanning Xray diffraction [14 -16]. White beam has
been used for geometrical calibration
with silicon wafer. The example shown
here is related to a 300nm thick tungsten
film prepared by direct ion beam
sputtering. The images obtained by
optical microscopy (left) are similar to
the corresponding iso stress maps
(right).
15
It is also worth noting that plastic anisotropy may also induce large grain to grain
stress differences [17] because of different orientation-related resolved shear stresses. Another
source of stress inhomogeneities in polycrystalline films is the anisotropy of thermal
expansion coefficient (TEC). A striking example of this latter phenomenon is NiSi. NiSi is
orthorhombic (MnP structure a = 0.5233 nm, b = 0.3258 nm, and c = 0.5659 nm) and exhibits
an amazingly large anisotropy in TECs: αa = 42, αb = –43 and αc = 34 10-6 K-1 [18, 19].
Preliminary experiments are underway at ALS to investigate such grain-to-grain stress
variations in NiSi films. NiSi is the silicide to be used in future advanced CMOS technologies
(beyond 65 nm channel length).
Finally, we note that stress distributions within individual grains have not been studied
experimentally at this length scale. However, in a recent microdiffraction study of a 1500 nm
unpassivated annealed blanket Cu film prepared by sputter deposition and having a large
grain size (> 3 µm), M.A. Phillips et al. [20] found very wide stress distributions within
individual grains. This work suggests that local variations in dislocation structure may also
play a significant role in establishing stress variations within films and nanostructures.
In summary the ability to analyse local mechanical stresses is very important both from a
-fundamental understanding view point:
Clearly, the simple scaling laws that have been developed for bulk materials
are incomplete. By understanding the deviations from these empirical rules that
arise in small dimensions, we hope to better understand deformation processes
at all length scales.
-
technology view point:
As applications for nanofabricated devices expand far beyond microelectronics
in the coming years, the level of integration and the variety of materials that
will be integrated will increase rapidly. This will inevitably lead to large
stresses and stress gradients. By developing tools for understanding stress
heterogeneities in these structures, and by determining the main links between
stress distributions and mechanical behaviour in metallization, we will provide
both information of use in current technologies as well as means for obtaining
data in future technologies.
This short argumentation stresses the need for sub-micrometer x-ray diffraction in order to
evaluate local strains. As already pointed out in the introduction intergrain strains may only
be determined provided no sample rotation is performed. Indeed there are no available
rotation stages with a SOC radius smaller that 1 micrometer. This calls for Laue diffraction
using a white x-ray beam. The experiments [1-4] which have been performed so far at ALS
indicate very clearly the power of this method. One should, however, recognize the necessity
of coupling this method with monochromatic diffraction. Indeed Laue diffraction will only
yield the deviator part of the strain tensor. It is thus necessary to identify the energy of at least
one of the Laue spot to get the dilatational part and then a full strain tensor evaluation. This is
what is performed at ALS.
A monochromatic beam may also be useful for performing at the same time local
chemical measurements with XRF, which is important also for issues such as electromigration
or reactivity where stress and local composition are interrelated. Local atomic environment
may also be evaluated with the help of EXAFS and XANES (important e.g. for gas sensors).
The two last examples stress also the need for in situ measurements: during temperature
ramping, gas exposure, electromigration testing, laser emission … This calls for a
“reasonable» working distance between the sample and the focusing optics in order to have
16
enough space for the sample environment (furnace, x-ray transparent dome, mechanical
testing …).
Within STRESSNET white beam microdiffraction has been recognized as a key tool
to evaluate local stresses in lines, dots or even devices. As a result a project for implementing
white beam microdiffraction on the French CRG BM32 at ESRF has been accepted.
Expectations are 0.5 x 0.5 µm2 focus beam using KB mirrors with a photon flux of 2.5 1012
photons/s in a 5-30 keV energy range. Beam line upgrade is in progress and the first micro
focussed WB is expected middle of 2006 year. Within that particular project, about 10% of
the total beam time of the line will be devoted to white beam microdiffraction. Such a small
amount of time is clearly insufficient considering the expected needs but it is a reasonable
compromise since BM32 has a strong activity in surface and interface science.
REFERENCES
_______________________________________________________________________________________________________________
[1] A.A. MacDowell, R.S.Celestre, N. Tamura, R. Spolenak, B. C. Valek, W.L. Brown, J.C.
Bravman, H.A. Padmore, B. W. Batterman, J. R. Patel, Submicron X-ray diffraction, Nuclear
Instruments & Methods in Physics Research A 467-468, 936 (2001).
[2] B. C. Valek, J. C. Bravman, N. Tamura, A. A. MacDowell, R. S. Celestre, H. A. Padmore,
R. Spolenak, W. L. Brown, B. W. Batterman, J. R. Patel, Electromigration-induced plastic
deformation in passivated metal lines, Applied Physics Letters 81, 4168 (2002).
[3] N. Tamura, A. A. MacDowell, R. Spolenak, B. C. Valek, J. C. Bravman, W. L. Brown, R.
S. Celestre, H. A Padmore, B.W. Batterman, J. R. Patel, Scanning X-ray microdiffraction with
submicrometer white beam for strain/stress and orientation mapping in thin films, J.
Synchrotron Rad. 10, 137 (2003).
[4] R. I. Barabash, G. E. Ice, N. Tamura, B. C. Valek, J. C. Bravman, R. Spolenak, J. R. Patel,
Quantitative Analysis of Dislocation Arrangements Induced by Electromigration in
passivated Al (0.5 wt% Cu) Interconnect, Journal of Applied Physics 93, 5701 (2003).
[5] I.A. Blech and A.A. Levi, J. Appl. Mech 48, 442 (1981).
[6] A.I. Sauter, W.D. Nix, Thermal stresses in aluminum lines bonded to substrates, IEEE
Transactions on Components, Hybrids, and Manufacturing Technology 15, 594 (1992).
[7] P. Lu, H. P. Lee, C. Lu, S. J. O’Shea, Surface stress effects on the resonance properties of
cantilever sensors, Physical Review B 72, 085405 (2005).
[8] S. Rigo, P. Goudeau, J.-M. Desmarres, T. Masri, J.-A. Petit and P. Schmitt, Correlation
between X-ray Microdiffraction and a developed analytical model to measure the residual
stresses in suspended structures in MEMS, Microelectronics Reliability 43, 1963 (2003).
[9] P. Goudeau, N. Tamura, B. Lavelle, S. Rigo, T. Masri, A. Bosseboeuf, T. Sarnet, J.-A.
Petit, J.-M. Desmarres, X-ray diffraction characterization of suspended structures for MEMS
applications, Mater. Res. Soc. Symp. Proc. 875, O4.11.1 (2005).
[10] A. Loubens, R. Fortunier, R. Fillit, O. Thomas, Simulation of local mechanical stresses
in lines on substrate, Microelectronic Engineering 70, 455 (2003).
[11] S.P. Baker, A. Kretschmann, E. Arzt, Thermomechanical behavior of different texture
components in Cu thin films, Acta Mat. 49, 2145 (2001).
17
[12] P. Gergaud, P. Goudeau, O. Sicardy, N. Tamura and O. Thomas, Residual stress analysis
in micro and nano structured materials by X-ray diffraction, International Journal of
Materials Product and Technology (2005) in press
[13] D. Jawarani, H. Kawasaki, I.- S. Yeo, L. Rabenberg, J. P. Stark, P. S. Ho, In situ
transmission electron microscopy study of plastic deformation and stress-induced voiding in
Al-Cu interconnects, J. Appl. Phys. 82, 1563 (1997).
[14] P. Goudeau, P. Villain, N. Tamura, H. A. Padmore, Mesoscale x-ray diffraction
measurement of stress relaxation associated with buckling in compressed thin films, Applied
Physics Letters 83, 51 (2003).
[15] C. Coupeau, P. Goudeau, L. Belliard, M. George, N. Tamura, F. Cleymand, J. Colin, B.
Perrin, J. Grilhé, Evidence of plastic damage in thin films around buckling structures, Thin
Solid Films 469-470, 221 (2004).
[16] P. Goudeau, N. Tamura, G. Parry, J. Colin, C. Coupeau, F. Cleymand, H. Padmore,
Strain mapping on gold thin film buckling and silicon blistering, Mater. Res. Soc. Symp.
Proc. 875, O10.4.1 (2005).
[17] D.E. Nowak, O. Thomas, E. Stach, and S.P. Baker, X-Ray Diffraction Analysis and
Modeling of Strain Induced by Thermal Cycling in a Thin Aluminum (011) Bicrystal Film,
Mat. Res. Soc. Symp. Proc. 695, 3 (2002).
[18] C. Rivero, P. Gergaud, O. Thomas, M. Gailhanou, B. Froment, H. Jaouen, V. Carron
Combined synchrotron x-ray diffraction and wafer curvature measurements during Ni-Si
reactive film formation, Appl. Phys. Lett. 87, 041904 (2005).
[19] C. Detavernier, C. Lavoie, F. d’Heurle, Thermal expansion of the isostructural PtSi and
NiSi: Negative expansion coefficient in NiSi and stress effects in thin films, J. Appl. Phys. 93,
2510 (2003).
[20] M.A. Phillips, R. Spolenak, N. Tamura, W.L. Brown, A.A. MacDowell, R.S. Celestre,
H.A. Padmore, B.W. Batterman, E. Arzt, J.R. Patel, X-ray microdiffraction: local stress
distributions in polycrystalline and epitaxial thin films, Microelectronic Engineering 75, 117
(2004).
18
Metallurgy and mechanics
1- Mechanical heterogeneities in materials and structures, and their consequences.
The community in "Mechanics of Materials, Structures, and Processes" is globally
interested by the relation existing between the structure of an object (global geometry for
parts of large dimensions, microstructures for composite materials) and its mechanical
properties. The fields covered by the research programs are broad, from complex theoretical
developments (eg. the formulation of scale transition problems or of failure theories) up to
applied research (eg. life time of a particular mechanical part under service). Most studies are
carried out in collaboration with an industrial partner.
Figure 1. The heterogeneities of the mechanical fields can be considered at different scales:
From right to left, nanometer (individual lattice defect), micrometer (collective behaviour of
lattice defects), few tenth of micrometers (intergranular interactions), or centimeters
(mechanical structure).
One aspect that is shared by all these domains is the description of heterogeneities, at the
adequate scale (fig. 1). For structure of large dimensions (larger than a few mm), one
generally considers that the material is homogeneous and the heterogeneous stress and strain
fields are linked to the geometry of the structure and to the applied forces. At a smaller scale
(typically a few micrometers), the heterogeneity of the material must be considered: presence
of grains in polycrystalline materials, inclusions / fibres in composites materials, etc... This
structural heterogeneity generates significantly heterogeneous stress and strain fields inside
the material, with strong variations at the micrometer scale. For example, under a simple
cooling (even slow), an intense and complex residual stress field develops in an initially stress
free polycrystal because of the anisotropy of the thermal expansion coefficient at the grain
scale. At an even smaller scale, lattice defects, precipitates, alloying elements ... are not
homogeneously distributed and thus build up heterogeneous mechanical fields. For example,
19
a single dislocation distorts and curves the crystal lattice. These features play a key role in the
overall mechanical behaviour of the material and of the structure. The characterization of the
heterogeneities at all scales is crucial since, for instance, a material does not fail in response
to the mean applied stress, but it is the maximum stress that build up locally at the most
unfavoured position which determines the overall strength of the material. Significant efforts
in experimental and numerical studies aims precisely at a better description on the strain
heterogeneities whitin heterogeneous materials, see for instance [1, 5].
An additional difficulty arises due to the fact that, generally, the material’s behaviour
strongly evolves during loading (crack propagation, increase of the dislocation density, phase
transformation, texture development, diffusion, recrystallisation, defects annihilation,
formation of precipitates, etc...) with often a coupling between these various mechanisms. For
example, the process of welding activates simultaneously several phenomena (diffusion of
alloying element, phase tranformations, local plasticity, recrystallization, thermal
deformation) with a gradient of activation with respect to the distance from the welding zone.
The resulting material microstructures are highly complex and generally uncontrolled.
2- Which information do diffraction experiments provide?
X-ray diffraction is unavoidable. Indeed, diffraction is the only technique allowing a
quantitative measurement of the elastic deformations at a small scale. The measurement is
representative of a given volume (the gage volume) and is obtained with a given precision,
both of which depending on the experimental setup. The quantities required in Mechanics
being generally tensors, the complete determination of the elastic deformation requires at least
6 measurements along 6 independent directions, and this for a single location. Practically, two
setups can be used to fulfil this goal:
• when using a monochromatic beam, the specimen needs to be rotated successively about
the measurement point, but care should be taken that the investigated region of the
material remains the same for all successive acquisitions,
• when using a white beam, rotations are no more necessary but a 2D detector is needed for
the acquisition of the Laue pattern.
The first solution is clearly not realistic for beam cross section smaller than 20-30 microns.
Engineers often prefer to speak in terms of stress rather than of elastic strain. Both
quantities are of course linked by the constitutive relation at the scale of the gage volume. But
this law can be easily determined only when the measurement is intragranular, i.e. when the
beam cross section is smaller than the grain size. More generally, it is complex. It requires the
use of scale transition schemes and a perfect knowledge of the consequence of all activated
mechanisms on the distribution of the mechanical fields [6 – 8]. For the case of cooling, for
instance, it is essential to be able to calculate the intergranular interactions, which themselves
depend on the microstructure (crystallographic texture, grain morphology and topology, ...).
On the other hand, several models have been proposed in the literature as for instance the
interpretation of the distribution of elastic strain in terms of density and arrangement of lattice
defects (fig. 2) [9 - 12].
Clearly, diffraction is a characterization tools complementary to other numerous
techniques currently used in research laboratories (SEM, TEM, EBSD, mechanical tests,
nanoindentation, AFM, microextensometry, numerical simulations, etc...).
3- The needs in Mechanics of Materials.
Two kinds of setups appear necessary at the SOLEIL synchrotron.
20
Figure 2. Laue diagram obtained at the ALS microdiffraction beamline 7.3.3., on a single
grain of a 15% tensile deformed Zr specimen (Left). Assuming that dislocations are mostly
located in a prismatic plane (prismatic slip is the easiest slip system for zirconium alloys), the
shape of the Laue pattern can be nicely reproduced by the technique proposed in [9] (Right).
For the characterization of structures with large dimensions (centimetric or more), or for
the intragranular analysis of polycrystals with large grains (100 µm or more), a diffractometer
with a "weakly" focussed beam (beam cross section of few tens of micrometers) is necessary.
This kind of setup would allow the realization of "stress map" eg. on industrial parts or on
multicrystalline specimens, with a spatial resolution of a few tens of micrometers. Using a
monochromatic beam, this could be adapted to the existing beamlines (DIFFABS /
CRISTAL), but only if the sphere of confusion of the goniometers is small enough and well
characterized. It can be noted that, if the geometric defects of the goniometer are
reproducible, they can be corrected by small translation of the specimen. The use of a white
beam and a 0-D detector with energy discrimination makes the setup easier but at the expense
of a resolution loss which can be critical for some specific applications. Even if this kind of
setup is relatively common on synchrotron sources, it would be a great advantage for the
Mechanics of Materials to have access to one such a facility on a national source. A
microdiffraction experiment in monochromatic mode has been applied at the ESRF beamline
ID22 [13] to plastically deformed zirconium samples and has revealed a very high level of
intragranular residual stress, of the some order as the yield stress of the material (fig. 3).
For studying the behaviour of materials exhibiting a fine grain structure (micrometric
grain size as in most industrial materials), or for the investigation of very small structures
(microtechnology, or small mechanical compounds, or very small detail such as a crack tip of
a larger compound), a characterization with a (sub)micrometric beam would allow significant
progress in numerous research fields:
• All problems linked to the surface modification (galvanisation, nitridation, machining,
oxidation, etc...) create very strong gradients in properties close to the material surface, at
depth generally not larger than few tens of micrometers. These gradients can be
determined at present only by some complex data treatment (leading thus to increasing
uncertainties) performed at a larger scale.
• Since about 5 years, numerous research projects concerning the development of metals
with submicrometric grain size have been supported by the French public research
21
organizations (Ministry of Research, CNRS ...) and industries (Arcelor ...). These
materials exhibit a significantly enhanced strength and could thus allow going further in
several technological applications such as eg. reducing the weight of moving structures
(cars and planes for instance).
• Several large industrials groups, in collaboration with the CNRS and the research
Ministry, support since few years ambitious research projects aiming at the integration of
all characteristic scales in structure calculations. The aim of the projects PERFECT,
SINERGY, SMIRN (EDF – Framatome – CEA) is to link the behaviour at the atomic
scale to the one of the large scale structure making up nuclear installations. The MAIA
project (DGA, DPAC, CNES, ONERA, SNECMA), which aims at preparing future
technologies in the field of aeronautic propulsion, is based on the description of the
heterogeneous response of the material at all relevant scales, from the finest scale present
in the material up to the complete behaviour of the engine.
Figure 3. Bragg reflexions measured on a 2-D detector, for a reference Zr powder (left) and
a plastically deformed Zr specimen (right, same material as in figure 2). For this last
specimen, the deviation from the theoretical Bragg angle indicates a fluctuation of the
intragranular stress of about 100 MPa, i.e. of the same order than the yield stress of the
overall material. The microdiffraction setup developed at the ESRF beamline ID22 allowed
single grain diffraction with a spatial resolution of few tens microns. From [14].
Clearly, such projects are possible only by the simultaneous development of theories,
numerical calculation, and experimental observations which must be adapted to the different
scale of interest, from the atomic scale to the one of the whole structure. In particular, the
experimental techniques for a characterization at the submicrometer scale develop rapidly and
significantly in almost all laboratories dealing with Materials Science: mechanical
interpretation of nanoindentation tests [15], large use of Atomic Force Microscopes,
numerous proposal for the acquisition of FEG SEM, automatization of the Orientation
Imaging Microscopy technique under SEM and TEM [16, 17], tentative use of Kossel
diagrams into SEM [18], development of the microextensometry with micrometric resolution
[1], etc... There is thus a real need to "go to the finest scales" for a better understanding of the
behaviour of industrials materials, for the development of future materials, for the
improvement of industrial processes, and more generally to understand what happens really in
a deforming material.
The laboratory diffraction setups benefit from the recent advances in X-ray optics, but
they will never be able to reach the micrometer scale spatial resolution. The creation of a
22
specific microdiffraction beamline at SOLEIL is thus the necessary complement of the
development of all other experimental equipment available in the research laboratories. A
large number of applications are considered on such a beamline. It is worth noting however
that very few national or international research projects have been proposed up to now on
microdiffraction beamline worldwide, such as the ALS beamline 7.3.3, in the field of
Mechanics of Materials. Our feeling is that the actual possibility of performing an X-ray
characterization at the micrometer scale is not well known in the community. There is thus a
large field of investigation leading to promising discoveries and applications. In Europe, the
main uses of small X-ray beams adapted to the mechanics of Materials are probably done at
the ESRF (beamline ID11), but the principal developments of this beamline aim at performing
3D characterizations. Unfortunately, 3D techniques cannot be coupled to most laboratory
experiments, which are generally 2D because they are limited to the observation of the
material surface. This feature limits thus the possible interpretation of 3D characterizations.
The French community needs a microdiffraction beamline whose main characteristics are:
a beam with a micrometric (or less if possible) cross section, mono- and poly-chromatic,
energy range 5-25 keV, for the analysis of the elastic deformations and related stresses, of
multiples phases, and of local crystal orientations. It appears particularly important to be able
to perform scans in the depth of the material (limited to the attenuation length at the current
wavelength) in order to evaluate surface gradients. And more particularly, it would be of great
interest to investigate only the real surface region of the material (i.e. not more than a few
micrometers in depth), thus working with a more or less spherical gage volume, so that
microdiffraction observations can be really compared to other laboratory experiments such as
SEM. Several colleagues have also mentioned their interests for experiments at low/high
temperatures (from -150°C to 1000-1200°C), as well as under in situ mechanical testing.
The monochromatic beam setup, complementary to the white beam one, is necessary to
evaluate the hydrostatic part of the stress and elastic strain tensors and also since white beam
measurements are not sufficient for the determination of the local stress in elastically
anisotropic materials..Indeed, most deformation processes are sensitive to the complete stress
tensor, and not only to its deviatoric part. For instance, the normal stress in a zirconium
crystal controls the spreading of the dislocation core in the different crystallographic planes,
and it is thus believed to have a large influence on the activated slip system. Concerning
material damage, crack formation can occurs under pure hydrostatic stress. The evaluation of
the complete stress tensor is thus of high interest for most study.
We have received several projects of experiments from different laboratories in France. A
significant part of the French community is organised into two research federations, in the
regions Ile-de-France (F2Mmsp) and Rhone-Alpes (Fédérams). The laboratories associated to
the high school ENSAM are in close collaboration with each other and structured in network.
It is also worth noting the existence of the “Groupe d’Etude et de Recherche” GER MECAM
which is constituted by several laboratories and industrials of the east of France.
As already mentioned, most research project in the domain of Mechanics of Materials are
performed in relation with industrials partners. However, the particular interest of (at least)
EDF, FRAMATOME, ARCELOR, and ONERA is worth noticing.
With the proposed white beam microdiffraction beamline proposed here and the
possibility of performing 3D scans close to the sample free surface, it will be possible to have
a surface characterization of the material, complementary to most other techniques used in the
laboratories and at a similar spatial resolution, and to analyse the stress distribution, which
cannot be obtained at the microscale by other techniques. Clearly, as for the EBSD technique
which is at present used by almost all research team dealing with experimental Material
23
Science, the microdiffraction technique should also receive a very large success due to its
exceptional potentialities.
REFERENCES
___________________________________________________________________________
[1] E Soppa, P Doumalin, P. Binkele, M. Bornert, S Schmauder, Experimental and numerical
characterisation of ``in plane'' deformation in two-phase materials, Comp. Mater. Sc. 21, 261
(2001).
[2] L. Delannay, O.V. Mishin, D. Juul Jensen, P. Van Houtte, Quantitative analysis of grain
subdivision in cold rolled aluminium, Acta Mater. 49, 2441 (2001).
[3] R.A. Lebensohn, O. Castelnau, R. Brenner, P. Gilormini, Study of the antiplane
deformation of linear 2-D polycrystals with different microstrutures, Int. J. Solids Struct. 42,
5441 (2005).
[4] H. Moulinec, P. Suquet, Intraphase fluctuations in nonlinear composites : a
computational approach, Eur. J. Mech. /A Solids 22, 751 (2003).
[5] G. B. Sarma and P. R. Dawson, Effects of interactions among crystals on the
inhomogeneous deformations of polycrystals, Acta Metallurgica et Materialia 44, 1937
(1996).
[6] N. Letouzé, R. Brenner, O. Castelnau, J.L. Béchade, M.H. Mathon, Residual strain
distribution in zircaloy-4 measured by neutron diffraction and extimated by homogenization
techniques, Scripta Mater. 47, 595 (2002).
[7] M. FRANÇOIS, From strains determined by X-ray diffraction to residual stresses, a
procedure which is not so simple as it would seem, Rev.metall. (Impr.) 100, 1136 (2003).
[8] R. Levy-Tubiana, A. Baczmanski, A. Lodini, Relaxation of thermal mismatch stress due
to plastic deformation in an Al/SiCp metal matrix composite, Mater. Sci. Engin. A341, 74
(2003).
[9] R.I. Barabash, G.E. Ice, F.J. Walker, Quantitative microdiffraction from deformed crystals
with unpaired dislocations and dislocation walls, Journal of Applied Physics 93, 1457 (2003).
[10] M. Wilkens, Phys. Stat. Sol. A 104 K1 (1987).
[11] T. Ung!ar, I. Groma, M. Wilkens, J. Appl. Cryst. 22, 26 (1989).
[12] F Szekely, I Groma, J Lendvai, Statistic properties of dislocation structures investigated
by X-ray diffraction, Mat. Sci. Eng. A 309, 352 (2001).
[13] O. Castelnau, M. Drakopoulos, C. Schroer, I. Snigireva, A. Snigirev, T. Ungar,
Dislocation density analysis in single grains of steel by X-ray scanning microdiffraction,
Nucl. Instr. and Meth. A, 467-468, 1245 (2001).
[14] O. Castelnau, J.L. Béchade, R. Brenner, T. Chauveau, B. Bacroix, T. Ungar, M.
Drakopoulos, A. Snigirev, I. Snigireva, Single grain analysis of the plastic behavior of a
polycrystalline Zr alloy with a X-ray microdiffraction technique, Europ. Conf. on Adv. in
Mechanical Behaviour, Plasticity and Dammage EUROMAT 2000, Tours (France), 7-9 nov.
2000, Eds. D. Miannay, P. Costa, D. François, A. Pineau, p. 911-916.
[15] C.F. Robertson, M.C. Fivel, A study of the sub-micron indent-induced plastic
deformation, J. Mater. Res. 14, 2251 (1999).
24
[16] Electron Backscatter Diffraction in Materials Science-US-ISBN:030646487X, Schwartz,
Adam J. (EDT) /Kumar, Mukul (EDT) /Adams, Brent L. (EDT) /Publisher:Kluwer Academic
Pub Published 2000/08
[17] S. Zaefferer, Application of orientation microscopy in SEM and TEM for the study of
texture formation during recrystallizsation processes, Mater. Sci. Forum, 495-497 3 (2005).
[18] P. Dubos, S. Berveiller, K. Inal, A. Eberhardt, E. Patoor, Inter and intra granular strain
analysis by Kossel micro-diffraction, Colloque "Engineering applications of neutrons and
synchrotron radiation", 13-14 sept. 2004, ESRF-ILL (Grenoble – France).
25
2.B 2nd Circle: PRIORITY for monochromatic diffraction, white beam optional
Art and Archeology
1. Introduction [1]
Materials science is a very active discipline in both archaeology and art conservation.
Physico-chemical analyses reveal pertinent information which cannot be gained from art
historical investigations only. Among the analytical tools used in materials science,
synchrotron radiation (SR) techniques provide powerful and complementary ways to
interrogate ancient artifacts and artwork as unique records of our physical and cultural past.
Over the past years, there has been a strongly increasing demand for access to SR-based
techniques such as X-ray imaging, X-ray diffraction (XRD), X-ray absorption, X-ray
fluorescence, X-ray tomography and IR spectroscopy (Fig. 1). Most SR techniques offer the
advantage to be non-destructive and can apply on a statistically significant number of samples
or on representative volumes at different length scales (from mm to µm). XRD so far covers
46% of the SR studies on cultural heritage (Fig. 1). It has also been shown that fruitful and
innovative co-operations between SR facilities, museums and institutes for archaeology,
conservation and restoration can be developed.
Nowadays, both ion-beam and X-ray beam techniques allow the direct (non-destructive or
in situ) observation of objects, at the mm-to-µm scale. The elemental analysis of major/minor
chemical species and the measurement of chemical concentrations and gradients can now be
carried out on museum objects or samples. At a synchrotron beamline, there is often a
successful combination of:
1. elemental analysis (XRF)
2. study of both the oxidation state and the site environnement of the chemical elements
of interest (XAS, XANES)
3. structural analysis (XRD).
In addition to macroscopic investigations (in the mm range), synchrotron micro-beam
based analytical methods and their combination offer a unique, tunable X-ray microscopic
probe on artifacts and archaeological objects. As a matter of fact, SR micro-beam techniques
already represent 63% of the SR publications applied to cultural heritage (Fig. 1).
Measuring both the chemical and phase speciations is important for far-extending range of
materials (metals, ceramics, minerals, organic and soft condensed matter…) and in a large
number of cases:
1. identification and relative proportions of the elements and of the source materials
2. artificial or natural, chemical or mechanical transformations of archaeological
materials: surface deposits of mineral traces in relation with how the object was used,
oxido-reduction reaction products in alloy-containing patinas or in fired clays,
pigments in paintings, corroded metallic objects…
3. defects and damage considered as a fingerprint of the manufacturing process (heating,
crushing, graving, chemical treatment).
[1] This project is supported by the CNRS-GDR consortium entitled “Matériaux du patrimoine et synchrotron
SOLEIL”. Its main objectives are to promote and help research programmes on materials of the cultural heritage
at the SOLEIL synchrotron (see details at http://www.gdr2762-cnrs.fr/). The GDR initiates projects using the
current and potential applications of synchrotron techniques applied to relevant problems in archaeology and art
conservation. This interdisciplinary GDR is composed of synchrotron practitionners and experts in the
disciplines of Archaeology, Archaeological Science, Art Conservation and Materials Science. The use of Large
Infrastructures as analytical Facilities for historical/archeological investigations is now acknowledged as an
important issue (e.g. see reports from the Research Infrastructure Unit of the Research Directorate General of the
European Commission).
26
Figure 1 : SR-related publications in the field of cultural heritage from Loïc BERTRAND
(Synchrotron SOLEIL),. The graphs show the proportions of XRD and microbeam
measurements. http://www.synchrotron-soleil.fr/patrimoine/
27
4. transformations of the materials responsible for their long-term conservation or in view
of their preservation.
5. expertise and identification of artifacts.
6. elemental and phase imaging and mapping of ancient materials
7. trace analysis for revealing the provenance and origin of the materials, and their
possible contamination during their preparation or in their environment.
2. Advantages of µ-diffraction
XRD is a routine technique for identifying crystalline phases in a material. In most cases,
the samples of interest are either extracted powders (cosmetics, pigments, …) or
polycrystalline materials which can sometimes be prepared as thin or resin-embedded cross
sections. Powder diffraction is therefore a well suited technique, which addresses a number of
archaeological pertinent problems:
- phase identification: preparation of the material.
- identification of minor phases: provenance/source or preparation of the material
- phase proportion: recipes
- structure solving of unknown phases, resulting from ageing, alteration, manual
transformation or when published models on analogues are inadequate.
- microstructure (XRD peak profile analysis): the preparation of the compounds, e.g.
crushing, sieving, heating, chemical transformation, affects the shape, the size
distribution and the deformation of the grains. The presence of such effects can be
revealed by the position and profile of the XRD peaks.
- texturing (e.g. orientation of the grains on a substrate, induced by the preparation
process).
However, the interpretation of the XRD patterns is often biased by a number of factors
inherent to archaeological materials:
- small (precious) volumes
- grain size and phase absorption heterogeneities
- texture and preferred grain orientation
- poorly crystalline phases
- large number of phases
- trace phases
- defects, disorder
- unknown compounds (whose JCPDF file is either inadequate or inexistent)
- presence of a matrix or a substrate
- fluorescent elements and amorphous phases.
For these reasons, it is often difficult to identify the trace phases or the ingredients in a
complex mixture. Quantitative XRD (phase proportions) is even more difficult. Further XRD
investigations (texture, microstructure or structure solving) are often out of reach.
In a number of cases, SR powder diffraction can help optimise the data quality: signal-tonoise and signal-to-background ratios, fluorescence elimination, higher angular resolution,
lower absorption factors. No one technique is sufficient: better results are obtained when
combining white and monochromatic XRD techniques, or coupling XRD and XRF….
In addition, the beam size can be adapted to the scale of observation or scale of
heterogeneity. A mm-sized beam is required for volume-average measurements.
Decreasing the beam size is critical in a number of studies:
28
1. f(z) or pseudo-stratigraphic profiles in order to measure the phase gradients in depth
(e.g. across the top layers of contamination/corrosion/alteration, or through the
successive chromatic layers of a painting cross-section, or from the gloss to the bulk
of a ceramic). See Figs. 2 and 3.
2. f(x,y) (spatially resolved) mapping over a surface (e.g. examination of motifs and
decorations made of different pigments, heterogeneous zones): 2 to 20µm beam size.
See Fig.4 [1].
3. The grain-by-grain analysis in Laue mode (white radiation) helps determine whether
the phase is present as inclusions, over local zones or homogeneously dispersed: 2 to
20µm beam size (Fig. 5) [2].
3. Requisites for µ-diffraction
In complex cases (multi-phased sample, insufficient number of diffracting particles), the
monochromatic-beam produces an incomplete XRD pattern which cannot be readily
interpreted as a powder diffractogram any more. Scanning the white beam over mono-phased
domains renders the phase identification simpler or less ambiguous (see Fig. 5: Sciau et al.
[2]. Due to the inherent difficulties of XRD work on such heterogeneous materials, the
optimisation of the data acquisition, versus the type of sample and nature of the expected
result, should rely on the possibility to alternate or combine different diffraction modes
(reflection/transmission, monochromatic/polychromatic, focussing/defocussing optics).
Acquiring the XRD data in the white-beam mode is also important whenever energydispersive X-ray spectroscopy is also required.
Unlike X-ray spectroscopic techniques (XAFS, XRF,…), the measurement of structural
(d-spacing, F2 modules) and microstructural (peak shape, Orientation Distribution Function)
parameters is highly dependent on the angular accuracy and intensity reliability of the XRD
pattern. A number of errors (sample displacement, 2θ error, absorption, surface roughness)
need to be minimised. Decreasing the beam size below 20µm drastically reduces the number
of illuminated Bragg-oriented grains in the material, giving rise to weak and/or heterogeneous
Debye-Scherrer rings. The use of a 2D detector is hence required. The interpretation of the 2D
XRD patterns should be done with a ready-to-use software: correction of detector aberrations
(flat field, pixel-to-angle correspondence, tilts), aberrant pixel masking (glitches, saturations),
automatic 2D image calibration (tilt angles, main beam position, ring eccentricities), data
reduction from 2D to normalised 1D patterns, automatic peak search and phase recognition,
instrumental broadening deconvolution. Phases should be recognised during the
measurement. The integration of XRD data processing in routine strategies is a bottleneck
which needs be considered with great care.
The need for dedicated strategies and special devices to bring/prepare/measure samples at
the SR facility: the constraints regarding the dimensions and handling conditions of the
samples and objects can be very different (from minute samples to cm-sized objects). Careful
alignment and positioning on a high-accuracy X-Y-Z-ω−χ−φ motorised heavy-duty stage are
required. Precise location of the beam impact on the sample is needed.
Associating the XRD patterns with their respective chemical XRF patterns is a major
requirement for phase assignment.
Tuning the beam size (from µm to sub-mm scales) enables to adapt the probe scale to the
scale of heterogeneity. For example, see figure 6 [3] : non-destructive XRD on archaeological
textile fragments yield diffraction diagrams with sharp and intense powder rings from the fine
adhering mineral particles (mineral inclusions of soil or of a colouring agent). XRD with large
beams (~0.2 mm diameter) produces broad diffuse rings from the small crystallites and from
the averaging over many fibres (cellulose or wool).
29
Figure 2 : The present study is part of a comprehensive study of the materials including
preparation, pigments, bindings and alterations as well as the painting techniques used by a
Catalan master Jaume Huguet (1415-1492). (top left) altarpiece of the Conestable; (top right)
detail of the zone where one sample was extracted and optical image of a cross section
showing the alteration layer (A), the green chromatic layers (B, C, D) and the preparation
layer (E). (bottom) 2D diffraction data (beamline 9.6 SRS Daresbury) collected in 30sec
(beam current < 20mA) at 14.25keV using a 100mm beam footprint. The spotty reflections
are mainly related to gypsum, while the rings corresponding to weddelite (Ca oxalate), lead
white and yellow pigments are very homogeneous and indicate the presence of fine particles
in these pigments. The rings corresponding to the green pigments (malachite, Cu acetate,
paratacemite, calumetite) show the presence of both fine particles and large crystallites.
From N. Salvado et al. J. Synch. Rad. 9 (2002).
30
Figure 3 : Micro-scan of thin sections of the black gloss of an Etruscan pottery at 1-5 micron
resolution and 2D pattern collection of 30sec/step. M. Burghammer, E. Pantos, ESRF, ID13.
31
Figure 4 : Study of the surface pigments on a Roman fresco (a) Photography of the fragment
of a Roman wall painting, Museum of Metz, France. The frame shows the analysed zone. The
60x60 pixel2 (pixel size = 0.1x1mm2) diffraction phase maps of the individual constituents:
(b) underlying preparation layer of calcite à Ca; (c) superficial calcite pigment à Ca; (d)
hematite à Fe; (e) goethite à Fe; (f) Egyptian Blue à Cu; (g) lead carbonate as transformed à
Pb. All images (b to g) are obtained by diffraction. (h) superposition of the Fe, Pb and Cu
fluorescence elemental PIXE maps; (i) superposition of the diffraction maps of the individual
phases. All individual maps use an arbitrary code of colors. (j) on transposing the colour
code of picture i, the diffraction-interpreted image reveals the main features of a Cupid's
face. E. Dooryhee et al. Appl. Phys. A (2005) ESRF-ID11.
32
2Θ
Θ
Χ
(a)
(b)
50
H
Intensity (a.u.)
45
(a)
40
H
35
30
25
H
20
H C
C H
H
H
Q C
C
Q
C
H
15
10
1.5
2.0
2.5
3.0
3.5
4.0
d (A)
2.74
2.74
2.76
1.28E4
9600
2.80
6400
3200
2.82
0
2.84
1.04E4
2.80
8800
8000
2.86
-0.84 -0.86 -0.88 -0.90 -0.92 -0.94 -0.96
X (m m )
(b)
2.74
X (m m )
2.74
2.76
2.76
2E4
1.7E4
1.4E4
2.80
1.1E4
8000
2.82
5000
2.84
2.86
2E4
1.66E4
2.78
Y (mm)
2.78
Y (mm)
9600
2.82
-0.84 -0.86 -0.88 -0.90 -0.92 -0.94 -0.96
1.32E4
2.80
9800
6400
2.82
3000
2.84
2.86
-0.84 -0.86 -0.88 -0.90 -0.92 -0.94 -0.96
(c)
1.12E4
2.84
2.86
(a)
1.2E4
2.78
Y (m m)
2.78
Y (m m)
2.76
1.6E4
X (m m )
-0.84 -0.86 -0.88 -0.90 -0.92 -0.94 -0.96
(d)
X (m m )
Figure 5 : Micro scanning X-ray diffraction study of Gallo-Roman Terra Sigillata ceramics
(top) XRD pattern recorded with a X-ray CCD detector: (left) Laue spots with white beam (513 keV) and (right) diffraction Debye-Scherrer rings with a 6keV monochromatic X-ray
beam. The two main diffraction angle axis, 2 and , are indicated with white arrows. (centre)
1D diffraction diagrams obtained after angular integration of the 2D diffraction images. The
A, C, H and Q letters refer to Anorthite, Corundum, Hematite and Quartz mineral species.
(bottom) Mineralogical maps obtained by integrating the intensity over a given diffraction
ring: (a) hematite at d = 2.7 Å, (b) corundum at d = 2.1 Å, (c) quartz at d = 2.3 Å , (d) quartz
at d = 3.36 Å. The scan size is 150 x 150 µm2 and it has been done with a step size of 5µm.
Ph. Sciau et al. Appl. Phys. A 2005. Beamline 7.3.3. ALS Berkeley.
33
Figure 6: From M. Müller, M.Z. Papiz, D.T. Clarke, M.A. Roberts, B.M. Murphy, M.
Burghammer, C. Riekel, E. Pantos and J. Gunneweg. Identification of textiles from the
Khirbet Qumran caves in Khirbet Qumran et Ain Feshkha, II. Études d'anthropologie, de
physique et de chimie, Fribourg, 2003.
34
X-ray microbeam (~2 to 5 µm) XRD yields fibre-like diffraction patterns from fractions
of single fibres in a few seconds. The high internal orientation of textile fibres makes it
possible to separate out the contributions from soil particles and from fibres in the diffraction
patterns. In a second example [4], transmission XRD analysis of parchments (200 µm beam
size) shows the composite diffraction features from the entire thickness. Single crosssectional (surface-to-surface) scans of 0.3mm thick sections of parchment are possible with a
1.5x15µm2 beam and show the detailed features present only in specific areas of the
parchment: orientation of collagen fibrils in the plane of the parchment, effects of laser
cleaning, mineral phases and crystalline lipids, material structure under an inked region,
alteration of the surface.
Another important point is the damage concern, especially in the presence of organic media or
with radiolysable materials such as silicate glasses. Using a micro-beam makes any possible
damage invisible to the naked eye and guarantees the long-term integrity of the artefact.
3. The target user community
At present, the French research teams most involved in SR micro-analysis in Art and
Archaeological Science and most susceptible to commit themselves in the development of the
beamline, its testing/commissioning and most likely to become proposers/users can be (non
exhaustively) found among the GDR partners (see http://www.gdr2762-cnrs.fr/).
The list of publications indicated below shows the variety of SR studies in the field of
cultural heritage and their relevance with micro-XRD. The materials of interest are : pigments
and pictorial layers [5], easel paintings, metals (corroded surfaces, ancient bronzes, ferrous
tools, inlays, slags, coins,…), cosmetics, parchments, textiles, (petrified) wood, (mineralised
or calcified) biomaterials (hair, skin, bone, tooth), travertine or marble monuments, ceramic
crucibles or moulds in foundry, pottery (slip and paste), enamels, lustres, glass and faience,
inks, … Many micro-XRD relevant questions and methods in cultural heritage are common
and should be shared with other domains: environmental and earth sciences, mineralogy,
astrophysics.
In their seminal article, Harbottle et al. [6] predicted that there is every reason to believe
that SR will quickly take a prominent place in archaeometric research. Should we conclude
here that there is every reason to believe that research in cultural heritage could significantly
benefit from a microdiffraction facility at SOLEIL.
4. Publications
About 60 articles have been published on this subject between 1986 and 2005: See Loïc
Bertrand: http://www.synchrotron-soleil.fr/patrimoine/
35
REFERENCES
[1] E. Dooryhée, M. Anne, I. Bardiès, J. L. Hodeau, P. Martinetto, S. Rondot, J. Salomon, G.
B. M. Vaughan, P. Walter, Non-destructive synchrotron X-ray diffraction mapping of a
Roman painting, Appl. Phys. A 81, 663 (2005).
[2] P. Sciau, P. Goudeau, N. Tamura, E. Dooryhée, Micro scanning X-ray diffraction study of
Roman Terra Sigillata ceramics, Applied Physics A (2005), in press
[3] M. Müller, B. Murphy, M. Burghammer, C. Riekel, M. Roberts, M. Papiz, D. Clarke, J.
Gunneweg, E. Pantos, Identification of ancient textile fibres from Khirbet Qumran caves
using synchrotron radiation microbeam diffraction, Spectrochim. Acta B 59, 1669 (2004).
[4] C. J. Kennedy, J. C. Hiller, D. Lammie, M. Drakopoulos, M. Vest, M. Cooper, W. P.
Adderley, T. J. Wess, Microfocus X-ray diffraction of historical parchment reveals variations
in structural features through parchment cross sections, Nano Lett. 4, 1373 (2004).
[5] R. R. Chianelli, M. Perez de la Rosa, G. Meitzner, M. Siadati, G. Berhault, A. Mehta, J.
Pople, S. Fuentes, G. Alonzo-Nunez, L. A. Polette, Synchrotron and simulation techniques
applied to problems in materials science: catalysts and Azul Maya pigments, J. Synchrotron
Rad. 12, 129 (2005).
[6] G. Harbottle, B. M. Gordon, et K. W. Jones, Use of synchrotron radiation in
archaeometry, Nucl. Instrum. Methods B 14, 116 (1986).
36
Mineralogy, Planetary and Earth Sciences
Introduction
Microdiffraction is an important tool in mineralogy, planetary and Earth sciences to study
the structure of small crystals and the texture of fine-grained assemblages in terrestrial rocks,
meteorites or environmental samples. Most work is being done with lab source X-ray
microbeams or electron beams, but synchrotron microbeams would now allow to extend such
studies profitably. Synchrotron radiation (SR) allows to work on much smaller crystals
(compared to focussed or collimated lab sources) and without the heavy sample preparation
which is requested for electron diffraction, transmission electron microcopy (TEM) or
electron backscattered diffraction (EBSD).
If HP studies and in situ experiments routinely use SR, other fields of interest in
mineralogy, planetary and Earth sciences such as phase identification and characterization,
texture analysis, thermal and deformation history seldom used SR so far, in part because of
the very limited availability of adequate beam-lines. A beam-line on Soleil dedicated to
microdiffraction with ancillary XRF chemical analysis, would allow to develop such novel
studies.
Applications
Applications in mineralogy, planetary and Earth sciences (exclusive of HP studies, which
usually require dedicated beam lines) can be classified in one or several of the following
categories. Categories 1 and 2 are very similar in methodology and technical requirements to
the "cultural heritage" topics exposed in this document, whereas category 3 is more specific to
mineralogy and might be closer to material science or microelectronics concerns.
1 - Phase identification :
a) Identification of phases in submicrometer mixtures.
An exemple is provided by studies performed by Alain Manceau and co-workers at the
ALS [1] who identified the carrier phases of heavy metals in soil nodules by a combination of
microdiffraction and microXRF. This type of application requires a monochromatic beam,
coupling with chemical analysis (at least XRF, possibly microXAS), a submicrometer beam,
and imaging capability.
b) Identification of micrometer-sized isolated grains in samples.
An exemple is provided by Ivanov et al. [2], who solved the structure of isolated
grains c. 10 µm large in a rare sample of meteorite (Fig. 1) by SR Laue microdiffraction, at
Tsukuba, Japan.
Figure 1 - BSE image of a portion
of the Kaidun meteorite. Minute
phosphide grains (arrowed) were
studied by SR Laue
microdiffraction. The structure was
solved and proved to be identical to
synthetic FeTiP.
37
2 - Texture analysis:
Texture analysis can be performed in one of two ways :
a) by analysis of the reinforcements of Debye-Scherrer rings, using a monochromatic
beam, when the grain size is smaller than the beam size;
b) or by determining the phase orientations and scanning the sample using a white
beam, when the grain size is larger than the beam size. This method is to be compared with
EBSD, which provides similar results. However, sample preparation for EBSD is very
difficult for insulating materials, and the use of SR white-beam microdiffraction would allow
to extend textural studies to new types of samples. SR white-beam microdiffraction also
offers a precision in the determination of the position of the reflections that allows to study
deformation and residual strains, which is seldom possible with EBSD.
3 - Mutual orientation of phases
Mutual orientation of crystals can be achieved by epitaxy, twinning, or exsolution of
phases. In all these cases, we are interested in determining the mutual orientation of the
phases and the residual stress at the interface, if any. Such information, in the case of
exsolutions, allow to constrain the thermal (or P-T) history of the sample, a major goal in
Earth and planetary sciences. So far, studying mutual orientation of phases is done by TEM
[3], on the determination of the thermal history of a martian meteorite from the exsolution
microstructures of pyroxenes) or by EBSD [4]. Similar studies could be performed by SR
microdiffraction using a white beam, with the advantages that contrary to electron diffraction,
sample preparation is easy for SR microdiffraction, and that it allows in situ and non
destructive studies, contrary to TEM.
Target users
As previously mentioned, SR microdiffraction is presently rarely used in mineralogy,
planetary and Earth sciences aside HP studies, in part because of the very limited availability
of adequate beam-lines. It nevertheless offers a very good potential for extending studies that
are currently conducted by electron diffraction techniques.
Figure 2 - SEM image of an
interplanetary dust particle collected
in the stratosphere. Such
extraterrestrial samples are
polyphasic and fine grained, and
their characterization requires
coupling of microdiffraction and
microanalysis, which can only be
achieved in a non-destructive way by
using SR.
In particular, scientists working on rare extraterrestrial samples are very much interested
in SR microdiffraction because it is non destructive and allows to work in situ from a section
or isolated grains [2]. This is important for studying rare meteorites, but even more so for
extraterrestrial samples collected from spatial missions: interplanetary dust particules (Fig. 2),
cometary dust, future missions with sample returns from asteroids or Mars. For those samples,
38
coupling phase identification by microdiffraction to micro-chemistry will be of prime
importance, and can only be achieved in a non-destructive way by SR white beam
microdiffraction. If the microchemical analyses of such samples can be performed on many
beamlines [5,6], very few beamlines offer the necessary coupling of white-beam
microdiffraction and microXRF, as well as proper spacial resolution.
REFERENCES
___________________________________________________________________________
[1] Manceau, Tamura, Celestre, MacDowell, Padmore, Unlocking Metal Sequestration in
Soils Nanoparticles, Eos. Trans. AGU 82, F1334 (2001).
[2] Ivanov, Zolensky, Saito, Ohsumi, Yang, Nononkova, Mikoushi, Florenskyite, FeTiP, a
new phosphide from the Kaidun meteorite, American Mineralogist 85,1082 (2000).
[3] Leroux, Devouard, Cordier, Guyot, Pyroxene microstructure in the Northwest Africa 856
martian meteorite, Meteoritics & Planetary Science 39, 711 (2004).
[4] Feinberg, Wenk, Renne, Scott, Epitaxial relationship of clinopyroxene-hosted magnetite
determined using electron backscatter diffraction (EBSD) technique, American Mineralogist
89, 462 (2004).
[5] Borg, Djouadi, Matrajt, Martinez-Criado, Snead, Somogyi, Westphal, In-situ analyses of
Earth Orbital grains trapped in aerogel, using Synchrotron X-ray microfluorescence
techniques, Lunar and Planetary Science XXXV, 1580 (2004).
[6] Ishii, Brennan, Luening, Pianetta, Bradley, Snead, Westphal, Hard x-ray spectromicroscopy techniques at SSRL for astromaterials analysis, Lunar and Planetary Science
XXXVI, 1393 (2005).
E. DiMasi, M. Sarikaya, Synchrotron x-ray microbeam diffraction from abalone shell, J.
Mater. Res. 19, 1471 (2004).
39
Life Sciences and Soft Condensed matter
Biology
Scientific background : Supramolecular and molecular architectures in cells and tissues
The structural organisation in cells and tissues is often directly related to their functions. For
instance, the mechanical properties of bone, hair or wood originates in the specific
hierarchical fibrillar structures of protein or polysaccharides. Similarly, the chemical barrier
functions of tissues are due, at the nano and micro levels, to a layered organisation of lipids
and, in some cases, to an additional composite structure such as that of the stratum corneum
(outermost layer of epidermis). Micro-XRD is a powerful technique for characterising the
molecular and supramolecular architectures and to follow their changes, either induced by
mechanical, thermal stresses or by pathological disorders which generally perturb, and even
destroy, the fine architecture.
In the field of plant biopolymers assemblies, microdiffraction has been shown to be very
efficient for mapping local orientation and crystallinity on starch and cellulose (in cell walls
and wood). Combining WAXS and SAXS allows to record very informative data on
orientation and dimensions of ordered regions in the global morphology (granule or fiber).
SAXS could also yield valuable information on the conformation of aggregated proteins in
storage bodies. Joint measurements with different applied stresses to sample (stretching or
indentation, drying/hydration, thermal treatments…) could be very useful to approach the
structure-property relationships of such assemblies.
In the field of animal tissues, micro-XRD is important to characterize the protein
architecture. Their crystallization grade is generally lower than that exhibited by plant
biopolymers, however the structural information which can be extracted from the fibre
diffraction patterns is sufficient to reveal and follow relevant parameters. It is therefore
sometimes possible to correlate the molecular architecture to the macroscopic mechanical
behaviour, to the hydration/chemical environment or even to pathologies. This technique
could offer novel opportunities in the domain of medical diagnosis and medical research.
These activities are mostly carried out on tissues, however the demand for experiments at the
cellular level is also increasing.
Technical needs
The data collection range for µ-XRD should cover both SAXS and WAXS regions in the
scattering vector range 0.005 Å-1 to 0.5 Å-1. The best detector is therefore a 2-D CCD detector
with at least a 120 millimetres in diameter entrance window. The typical time scale for rapid
data collections allowing to follow structural modifications in real time is about 1 to 5
seconds.
The beamsize range should extend from 0.1 to 10 µ m and the energy of the order of 10
to 15 keV. Attention must be paid to sample damaging of biological samples by X-ray beams;
a cooling sample holder is sometimes necessary. Therefore the experiments have to be
performed with a monochromatic beam.
An “on-line” optical microscope is necessary to choose accurately the sample zones. The
coupling of µ -XRD to µ -XRF is important for most applications, it allows to analyse and to
correlate the information at the same position on the sample. A Raman microprobe could also
be coupled, it would provide complementary information about molecular conformation. This
coupling has been recently achieved at the ESRF beamline ID13.
40
Investigation of human hair cuticle structure by microdiffraction
Direct observation of cell membrane complex swelling
A recent press release (2 september 2005) of Spring-8 describes results concerning the analysis of human hair
cuticle by X-ray microdiffraction :
“Structural Analyses of Human Hair Cuticle by Microdiffraction
The human hair cuticle is the outermost layer of hair fiber and composed of approximately 10 sheet-like cells,
called scales, stacked each other. The surface of the scale is covered by a thin layer of lipids. Between adjacent
scales, these lipids are separated by a layer of proteinous components. This triple-layered structure between
scales is called cell membrane complex (CMC). The CMC is an important pathway for penetration of molecules
into hair fiber. However, the penetration mechanism remains unresolved.
The joint research group of Basic Research Laboratory (Kanebo Cosmetics Inc.), Beauty Care Laboratory
(Kanebo Ltd.) and JASRI, has analyzed the structure of CMC by microdiffraction using the High Flux Beamline
BL40XU of SPring-8, and found that the structural change of CMC plays a key role in the penetration of dressing
chemicals into hair fiber.”
Indeed this study is a confirmation of a similar one carried out two years ago at the ESRF (1). X-ray
micro-diffraction is well-adapted to hair cuticle which gives rise to intense scattering signals despite of its few
micrometers thickness. Microdiffraction experiments with a 5 µm diameter beam were carried out at the ESRF
beamline ID13 revealing a characteristic small-angle X-ray scattering pattern for the cuticle. This pattern has
been assigned to the cell membrane complex (CMC) between each cuticle scale. Using a simple model of the
electron density within the CMC, values have been derived for the average thickness of the β- and δ-layers
which are close to those obtained by electron microscopy. In order to illustrate the potentialities of
microdiffraction in studying the properties of the cuticle, the effect of water-sorption has been monitored. Using
the intensity modelling described above, a 10% swelling of the δ-layer’s thickness has been observed. This study
shows that structural modifications of the CMC by physical or chemical stresses can be followed directly on the
cuticle of human hair fibres by microdiffraction analysis.
(1) Kreplak L., Merigoux C., Briki F., Flot D., Doucet J. "Investigation of human hair cuticle structure by
microdiffraction: direct observation of cell membrane complex swelling"B. B.Acta 1547(2), 268-274, (2001)
3000
Intensity (a. u.)
2500
2000
1500
1000
500
0
0
0.05
0.1
0.15
0.2
0.25
-1
S nm
One-dimensional profile after
subtraction of the small angle
background (open circles). The solid
curve is a least square fit derived from
a two-rectangular wells density model
of the CMC.
Drawing of a hair fibre. The two arrows labelled (a) and (b) indicate the
pathway of the X-ray beam. A detail of the cuticle has been enlarged to show
the position of the CMC with respect to the beam.
(a) SAXS pattern from the cortex, with its broad 8.8 nm equatorial peak.
(b) SAXS pattern from the cuticle. The equatorial broad peaks are due to
the scattering by the cell membrane complex (CMC).
The lines on patterns (a) and (b) show the tilt angle between the cuticle
scales and the hair axis. In order to emphasise the differences in peak
positions for the two patterns, a copy of the cortex SAXS pattern has been
added below the cuticle SAXS pattern.
41
Soft-condensed materials
Scientific background
Most µ-XRD experiments in the field of soft-condensed material are carried out on
polymers. The two major objectives are:
1) follow-up of stuctural parameters versus the precise position in the sample. X-ray
diffraction provides information from 1Å to 1000 Å, i.e. at the fibril scale (SAXS), at the
microfibril scale (SAXS/WAXS) and for the crystallographic unit-cell (WAXS). The chain
orientation, crystallinity grade, crystalline quality and residual stress, may differ at positions
only distant from a few micrometers, which explains the need for micro-analysis at the
micrometer or sub-micrometer resolution. Among the various examples are the issues of the
chain orientation within the spherulites, the crystallinity grade of the semi-crystalline polymer
through a plastic bottle wall, the residual stress and skin/core structure of fibres.
2) follow-up of the structural behaviour versus mechanical stresses. The stresses
(compression, stretching, shear, bending) are applied either in a static mode or in a dynamic
mode. The analyses aim at understanding the deformation processes at the molecular scale
and at determining the elastic moduli. These parameters will then be used in the deformation
modelling and in the prediction of ageing and failure processes. A micrometer beam size is
required to explore the various positions in the samples (or zones in samples) which can be as
small as a few micrometers. A high beam intensity is required to perform quick data
collection (sometimes at a sub-second time-scale) in order to follow deformation before
relaxation
processes occur.
Technical needs
The data collection range for µ-XRD should cover both SAXS and WAXS regions in the
scattering vector range 0.005 Å-1 to 0.5 Å-1. The best detector is therefore a 2-D CCD detector
with at least a 120 millimetres in diameter entrance window. The typical time scale for rapid
data collections allowing to follow structural modifications in real time is about 0.1 to 100
seconds.
The beamsize range should extend from 0.1 to 5 µm; a monochromatic beam in the range 10
to 15 keV is ideal.
An “on-line” optical microscope is necessary to choose accurately the sample zones. The
coupling of µ-XRD to a Raman microprobe is very important, it would provide
complementary information about molecular conformation during deformation. This coupling
has been recently achieved at the ESRF beamline ID13.
Interest from industry
Hard X-ray microdiffraction technique is already exploited by several companies in the
sector of bio-activities and transformation of bio-materials. The most active companies are the
cosmetics, agrochemical and pulp companies. The use of microprobe techniques is not
restricted to advanced research, it is also adapted to product development and control of
quality. Among these companies l’Oréal and Unilever are direct ESRF users, however many
other companies benefit indirectly of micro-diffraction facilities through collaboration with
academic laboratories.
Several academic laboratories are working on engineering issues related to polymers,
like l’Ecole Normale-Cachan, ESPCI-Paris and INSA-Lyon. They are generally working for
large companies like Arkema and Rhodia. However, most of the activity in the domain of
plastics is developed in Belgium (Solvay, Exxon,…), Germany (BASF, Bayer…), the
Netherlands (Shell, DSM, Philips…), United Kingdom (BP, ICI…) and Switzerland (Du
Pont,
Hunstamn..).
42
REFERENCES
Most of the following references are related to data collections carried out on beamline
ID13 at the ESRF. Among the overall 40 publications per year of this beamline, about 20
concern biological samples -animal and vegetal - and polymers; protein crystallography is not
included in these publications.
Biology – animals (1999 – 2005)
Baconnier S., Lang S.B., Calcite microcrystals in the pineal gland of the human brain: Second harmonic
generators and possible piezoelectric transducers, IEEE Transactions on Dielectrics and Electrical Insulation
11, 203-209 (2004)
Meek K.M., Boote C., The organization of collagen in the corneal stroma, Experimental Eye Research 78, 503512 (2004)
Riekel C., Rössle M., Sapede D., Vollrath F., Influence of CO2 on the micro-structural properties of spider
dragline silk: X-ray microdiffraction results, Naturwissenschaften 91, 30-33 (2004)
Rössle M., Panine P., Urban V.S., Riekel C., Structural evolution of regenerated silk fibroin under shear:
Combined wide- and small-angle X-ray scattering experiments using synchrotron radiation, Biopolymers 74,
316-327 (2004)
Fudge D.S., Gardner K.H., Forsyth V.T., Riekel C., Gosline J.M, The mechanical properties of hydrated
intermediate filaments: Insights from hagfish slime threads, Biophys. j. 85, 2015-2027 (2003)
Keckes J., Burgert I., Frühmann K., Mueller M., Kölln K., Hamilton M., Burghammer M., Roth S.V., StanzlTschegg S., Fratzl P., Cell-wall recovery after irreversible deformation of wood, Nature Materials 2, 810-814
(2003)
Lichtenegger H.C., Mueller M., Wimmer R., Fratzl P., Microfibril angles inside and outside crossfields of
Norway spruce tracheids, Holzforschung 57, 13-20 (2003)
Soellner C., Burghammer M., Busch-Nentwich E., Berger J., Schwarz H., Riekel C., Nicolson T., Control of
crystal size and lattice formation by starmaker in otolith biomineralization, Science 302, 282-286 (2003)
Dalconi M.C., Meneghini C., Nuzzo S., Wenk R., Mobilio S., Structure of bioapatite in human foetal bones: An
X-ray diffraction study, Nucl. instrum. methods phys. res., Sect. B Beam interact. mater. atoms 200, 406-410
(2003)
Ascenzi M.G., Ascenzi A., Benvenuti A., Burghammer M., Panzavolta S., Bigi A., Structural differences
between "dark" and "bright" isolated human osteonic lamellae, J. struct. biol. 141, 22-33 (2003)
Cedola A., Stanic V., Burghammer M., Lagomarsino S., Rustichelli F., Giardino R., Nicoli Aldini N., Fini M.,
Komlev V., Di Fonzo S., X-ray micro-diffraction analysis of reconstructed bone at Zr prosthetic surface with
sub-micrometre spatial resolution, Phys. med. biol. 48, N37-N48 (2003)
Kreplak L., Merigoux C., Briki F., Flot D., Doucet J., Investigation of human hair cuticle structure by
microdiffraction: direct observation of cell membrane complex swelling,, Biochimica et Biophysica Acta Protein
Structure and Molecular Enzymology, 1547(2), 268-274, (2001)
Bigi A., Burghammer M., Falconi R., Koch M.H.J., Panzavollta S., Riekel C., Twisted plywood pattern of
collagen fibrils in teleost scales: An X-ray diffraction investigation, J. struct. biol. 136, 137-143 (2001)
Busson B., Engström P. & Doucet J., Existence of various structural zones in keratinous tissues revealed by Xray diffraction, J. Synch. Rad. 6, 1021-1030 (1999)
Biology – plants (1997 – 2005)
Kölln, I. Grotkopp, M. Burghammer, S. V. Roth, S. S. Funari, M. Dommach, M. Müller., Mechanical properties
of cellulose fibres and wood - Orientational aspects in situ investigated with synchrotron radiation., J. Synchr.
Rad., in press.
43
M. Peura, M. Müller, R. Serimaa, U. Vainio, M.-P.Sarén, P. Saranpää, M. Burghammer.,Structural studies of
single wood cell walls by synchrotron X-ray microdiffraction and polarised light, Nucl. Instrum. Meth. B, in
press.
Roth S.V., Artus G.R.J., Rankl M., Seeger S., Burghammer M., Riekel C., Müller-Buschbaum P., Lateral
structural variations in thin cellulose layers investigated by microbeam grazing incidence small-angle X-ray
scattering, Physica B 357, 190-192 (2005)
Lemke H., Burghammer M., Flot D., Rössle M., Riekel C., Structural processes during starch granule hydration
by synchrotron radiation Microdiffraction, Biomacromolecules 5, 1316-1324 (2004)
Eichhorn S.J., Young R.J., Davies R.J., Riekel C., Characterisation of the microstructure and deformation of
high modulus cellulose fibres, Polymer 44, 5901-5908 (2003)
Keckes J., Burgert I., Frühmann K., Mueller M., Kölln K., Hamilton M., Burghammer M., Roth S.V., StanzlTschegg S., Fratzl P., Cell-wall recovery after irreversible deformation of wood, Nature Materials 2, 810-814
(2003)
Lichtenegger H.C., Mueller M., Wimmer R., Fratzl P., Microfibril angles inside and outside crossfields of
Norway spruce tracheids, Holzforschung 57, 13-20 (2003)
Moss C.E., Butler M.F., Mueller M., Cameron R.E., Microfocus small-angle X-ray scattering investigation of
the skin-core microstructure of lyocell cellulose fibers, Journal of Applied Polymer Science 83, 2799-2816
(2002)
Mueller M., Hori R., Itoh T., Sugiyama J., X-ray microbeam and electron diffraction experiments on developing
xylem cell walls, Biomacromolecules 3, 182-186 (2002)
Donald A.M., Astley O.M., Scattering studies of plant cell walls, Fibre diffr. rev. 10, 19-30 (2002)
Lai-Kee-Him J., Chanzy H., Mueller M., Putaux J.L., Imai T., Bulone V., In vitro versus in vivo cellulose
microfibrils from plant primary wall synthases: Structural differences, J. biol. chem. 277, 36931-36939 (2002)
A. Buleon, C. Gerard, C. Riekel, R. Vuong and H. Chanzy, Details of the crystalline ultrastructure of C-starch
granules revealed by synchrotron microfocus mapping, Macromolecules, 31, 6605-6610 (1998)
A. Buleon, B. Pontoire, C. Riekel, H. Chanzy, W. Helbert and R. Vuong, Details of the crystalline ultrastructure
of starch granules revealed by microfocus synchrotron mapping, Macromolecules, 30, 3952-3954 (1997)
Polymers and soft-condensed materials (2002 – 2005)
Structure and mechanical properties of carbon fibres: A review of recent microbeam diffraction studies with
synchrotron radiation, D. Loidl, H. Peterlik, O. Paris, M. Müller, M. Burghammer, C. Riekel., J. Synchr. Rad., in
press.
Modeling structural disorder within single poly(p-phenylenebenzobisoxazole) fibers using a submicrometer
synchrotron beam, Davies R.J., Burghammer M., Riekel C., Macromolecules 38, 3364-3370 (2005)
Crystallographic texturing in single poly(p-phenylene benzobisoxazole) fibres investigated using synchrotron
radiation, Davies R.J., Eichhorn S.J., Riekel C., Young R.J., Polymer 46, 1935-1942 (2005)
Local defects in thin polymer films: a scanning sub-microbeam grazing incidence small angle scattering
investigation, Müller-Buschbaum P., Roth S.V., Burghammer M., Bauer E., Pfister S., David C., Riekel C.,
Physica B 357, 148-151 (2005)
Crystal lattice deformation in single poly(p-phenylene benzobisoxazole) fibres, Davies R.J., Eichhorn S.J.,
Riekel C., Young R.J., Polymer 45, 7693-7704 (2004)
The use of synchrotron X-ray scattering coupled with in situ mechanical testing for studying deformation and
structural change in isotactic polypropylene, Davies R.J., Zafeiropoulos N.E., Schneider K., Roth S.V.,
Burghammer M., Riekel C., Kotek J.C., Stamm M., Colloid polym. sci. 282, 854-866 (2004)
X-ray microdiffraction study of the liquid crystal ordering in confined geometries, Francescangeli O., Ferrero
C., Stanic V., Lucchetti L., Burghammer M., Mol. cryst. liq. cryst. 412, 59/[1669]-67/[1677] (2004)
44
Spatially resolved flow-induced crystallization precursors in isotactic polystyrene by simultaneous small- and
wide-angle X-ray Microdiffraction, Garcia Gutiérrez M.C., Alfonso G.C., Riekel C., Azzurri F.,
Macromolecules 37, 478-485 (2004)
Investigation of structural processes during indentation of polymers by synchrotron radiation microdiffraction,
Garcia Gutiérrez M.C., Gourrier A., Riekel C., Journal of Macromolecular Science B - Physics 43, 267-277
(2004)
Stress oscillation-induced modulated phase transformation and yielding in syndiotactic polypropylene, Garcia
Gutiérrez M.C., Karger-Kocsis J., Riekel C., Chem. phys. lett. 398, 6-10 (2004)
Structural study of poly(L-lactic acid) spherulites, Gazzano M., Focarete M.L., Riekel C., Scandola M.,
Biomacromolecules 5, 553-558 (2004)
Microporous solid characterization: Use of classical and "new" techniques, Lozano-Castello D., CazorlaAmoros D., Linares-Solano A., Chemical Engineering Technology 26, 852-857 (2004))
Microbeam grazing incidence small angle X-ray scattering—a new method to investigate heterogeneous thin
films and multilayers, Roth S.V., Müller-Buschbaum P., Burghammer M., Walter H., Panagiotou P., Diethert A.,
Riekel C., Spectrochimica Acta B 59, 1765-1773 (2004)
Structure, deformation, and failure of flow-oriented semicrystalline polymers, Schrauwen B.A.G., Breemen
C.A.v., Spoelstra A.B., Govaert L.E., Peters G.W.M., Meijer H.E.H., Macromolecules 37, 9618-9633 (2004)
Analysis of stress transfer in two-phase polymer systems using synchrotron microfocus X-ray diffraction
Young R.J., Eichhorn S.J., Shyng Y.T., Riekel C., Davies R.J., Macromolecules 37, 9503-9509 (2004)
Formation of crystalline macrocyclic phases during electrophilic precipitation–polycondensation syntheses of
poly(arylene ether ketone)s, Zolotukhin M.G., Colquhoun H.M., Sestiaa L.G., Williams D.J., Rueda D.R., Flot
D., Polymer 45, 783-790 (2004)
Anisotropy of structure and transport properties in sulfonated polyimide membranes, Blachot J.F., Diat O.,
Putaux J.L., Rollet A.L., Rubatat L., Vallois C., Mueller M., Gebel G., J. membr. sci. 214, 31-42 (2003)
Single fibre deformation studies of poly(p-phenylene benzobisoxazole) fibres. Part II Variation of crystal strain
and crystallite orientation across the fibre, Davies R.J., Montes-Moran M.A., Riekel C., Young R.J., J. mater.
sci. 38, 2105-2115 (2003)
Elastic moduli of nanocrystallites in carbon fibers measured by in-situ X-ray microbeam diffraction, Loidl D.,
Peterlik H., Mueller M., Riekel C., Paris O., Carbon 41, 563-570 (2003)
Scanning microfocus small-angle X-ray scattering: A new tool to investigate defects at polymer-polymer
interfaces, Lorenz-Haas C., Müller-Buschbaum P., Wunnicke O., Cassignol C., Burghammer M., Riekel C.,
Stamm M., Langmuir 19, 3056-3061 (2003)
Rietveld refinement on X-ray diffraction patterns of bioapatite in human fetal bones, Meneghini C., Dalconi
M.C., Nuzzo S., Mobilio S., Wenk R.H., Biophys. j. 84, 2021-2029 (2003)
Multiple-scaled polymer surfaces investigated with micro-focus grazing-incidence small-angle X-ray scattering,
Müller-Buschbaum P., Roth S.V., Burghammer M., Diethert A., Panagiotou P., Riekel C., Europhys. lett. 61,
639-645 (2003)
The effects of schear and co-surfactants on the evolution of the micro-structure in concentrated dichain cationic
surfactant solution, Penfold J., Staples E., Tucker I., Hubbard J., Soubiran L., Creeth A., Fibre diffr. rev. 11, 6874 (2003)
The effect of hard segment ordering in copolyurethane elastomers obtained by using simultaneously two types
of diisocyanates, Prisacariu C., Olley R.H., Caraculacu A.A., Bassett D.C., Martin C., Polymer 44, 5407-5421
(2003)
Applications of micro-SAXS/WAXS to study polymer fibers, Riekel C., Nucl. instrum. methods phys. res., Sect.
B Beam interact. mater. atoms 199, 106-111 (2003)
45
Recent synchrotron radiation microdiffraction experiments on polymer and biopolymer fibers, Riekel C., Garcia
Gutiérrez M.C., Gourrier A., Roth S., Analytical and Bioanalytical Chemistry 376, 594-601 (2003)
Fast intracrystalline hydration of beta-chitin revealed by combined microdrop generation and on-line
synchrotron radiation Microdiffraction, Rössle M., Flot D., Engel J., Burghammer M., Riekel C., Chanzy H.,
Biomacromolecules 4, 981-986 (2003)
Rotational disorder in poly(p-phenylene terephthalamide) fibers by X-ray diffraction with a 100 nm beam, Roth
S., Burghammer M., Janotta A., Riekel C., Macromolecules 36, 1585-1593 (2003)
Fatigue behaviour of industrial polymers - a microbeam small-angle X-ray scattering investigation, Roth S.V.,
Burghammer M., Ferrero C., Diethert A., Müller-Buschbaum P., J. appl. crystallogr. 36, 684-688 (2003)
Self-assembled gradient nanoparticle-polymer multilayers investigated by an advanced characterization method:
Microbeam grazing incidence X-ray scattering, Roth S.V., Burghammer M., Riekel C., Müller-Buschbaum P.,
Diethert A., Panagiotou P., Walter H., Appl. phys. lett. 82, 1935-1937 (2003)
One-pot synthesis and characterization of soluble poly(aryl ether-ketone)s having pendant carboxyl groups,
Zolotukhin M.G., Colquhoun H.M., Sestiaa L.G., Rueda D.R., Flot D., Macromolecules 36, 4766-4771 (2003)
Ordering and director-field configuration in single droplets of liquid crystals probed by X-ray Microdiffraction,
Francescangeli O., Ferrero C., Lucchetti L., Simoni F., Burghammer M., Europhys. lett. 59, 218-224 (2002)
Cold drawing-induced mesophase in amorphous poly(ethylene naphthalate) revealed by X-ray Microdiffraction,
Garcia-Gutierrez M.C., Karger-Kocsis J., Riekel C., Macromolecules 35, 7320-7325 (2002)
Combined microindentation and synchrotron radiation microdiffraction applied to polymers, Gourrier A.,
Garcia-Gutierrez M.C., Riekel C., Macromolecules 35, 8072-8077 (2002)
Deformation studies of single rigid-rod polymer-based fibres. Part 1. Determination of crystal modulus, MontesMoran M.A., Davies R.J., Riekel C., Young R.J., Polymer 43, 5219-5226 (2002)
Texture of PAN- and pitch-based carbon fibers, Paris O., Loidl D., Peterlik H., Carbon 40, 551-555 (2002)
Evidence of elongated polymeric aggregates in Nafion, Rubatat L., Rollet A.L., Gebel G., Diat O.,
Macromolecules 35, 4050-4055 (2002)
46
3. BEAM LINE DESIGN AND OPTICS
The main prerequisites for a white (and monochromatic) micro beam experiments are:
-beam size as small as possible (less than 1 micron),
-flux as high as possible for the monochromatic mode but not too high for the white beam
mode due to the limitations of the CCD detector,
-energy range typically from 5 to 30 keV to ensure a good precision in strain
determination (number of Laue spots),
- working distance large enough (above 100mm) to allow for sample environments such
as furnaces, x-y stage, tensile stage etc..,
1 – Source
The need for a continuous polychromatic beam from 5 to 30 keV requires the use of either a
bending magnet source or a wiggler or possibly a tapered undulator. On SOLEIL, the only undulator
delivering a beam energy above 20 keV is the in-vacuum U20 and this technology is not compatible
with tapering. Thus, only two sources will be considered in the following: the bending magnet source
at 1° (R = 5.3 m) and the multipole wiggler W100 made of 18 periods of 100 mm inserted in a short
straight section. For the simulations, the electron energy is fixed at 2.75 GeV and the current at 500
mA.
For both types of sources, the flux emitted in the spectral interval 5 – 30 keV, is calculated after
the front end aperture (fig.1) and within the focused beam on the sample (fig. 6 and 9.)
The electron beam parameters for both sources are listed in table I and II.
Table I : parameters (RMS) of the bending magnet source
σx (µm)
60.1
σz (µm)
24.9
σ’x (µrad)
134.8
σ’z (µrad)
2.1
Table II : parameters (RMS) of the short straight section source (W100)
σx (µm)
388
σz (µm)
8.1
σ’x (µrad)
14.5
σ’z (µrad)
4.6
In figure 1 the spectral distribution of the flux transmitted through a 0.5×0.5 mm² aperture located
at 10 m from the source plane is displayed for both the bending magnet and the wiggler sources.
The integrated intensity transmitted in the whole spectral range 5 – 30 keV is found at: N = 2.5×1014
ph/s for the bending magnet source with a photon beam emittance of εx = 127×48 µm*µrad FWHM in
the horizontal plane and εz = 59×49 µm*µrad FWHM in the vertical plane which corresponds to a
brilliance of 1.42×107 ph/s/µm²/µrad².
The corresponding figures for the wiggler source are: N = 1×1016 ph/s for the integrated intensity
with horizontal emittance FWHM εx = 430×96 µm*µrad and vertical emittance εz = 18.7×49 µm*µrad
FWHM (brilliance: 2.60×108 ph/s/µm²/µrad²). For this particular aperture, the wiggler source is thus
18 times more brilliant than the bending magnet source.
47
12
Intensity (ph/s/eV)
10
Wiggler W100
Magnet
11
10
10
10
9
10
5
10
15
20
25
30
Energy (keV)
Figure 1 : flux transmitted in 50×50 µrad²
2 – Beamline Lay-out
The optical scheme for this beamline is strongly inspired from the ALS beamline 7.3.3. The
collected beam divergence is defined by the primary slits. The beamline comprises two focusing stages
(fig 2.). The first one consists in a toroidal mirror imaging the source on the secondary slits. The
second stage is made of two mirrors in Kirkpatrick-Baez configuration, focusing on the sample an
image of the secondary slit aperture. A beryllium filter, located downstream of the primary slits
absorbs the low energy part of the spectrum.
Source
Filter
Primary slits
KB mirrors
Toroidal
mirror
Secondary slits
Sample
Figure 2 : Proposed optical scheme for the white beam mode
With such an optical scheme, the resulting beam divergence on the sample is defined by the
angular acceptance of the whole beamline (width and position of the primary slit, size and angle of the
KB mirrors) and by the demagnification factor of the KB assembly. The ultimate beam size on the
sample is controlled by the secondary source size (aperture of the secondary slits), the demagnification
factor of the KB mirrors and the slope errors of these mirrors.
For either focusing plane (horizontal and vertical), the beam size FWHM is given by the
convolution of the geometrical size by the slope error induced broadening (formula 1). (assuming
gaussian distribution of slope)
q
s 2 = (s 1 ) 2 + ( 2 × 2.35 × q × ε ) 2
p
(1)
48
Where s1 is the secondary slit width, p is the distance between the secondary slits and the centre of the
corresponding KB mirror, q is the distance between the centre of the KB mirror and the sample and ε
the mirror slope error.
A trade-off has to be found to maximize the flux on the sample which leads to choose a
demagnification factor q/p balancing the two terms in formula 1.
The requested specifications for the ultimate beam size were 0.1 µm. A rough estimate of the
optimal lay-out to meet this objective is presented in the following paragraph. Since the results
contradict the other strong request of sufficient space around the sample, the detailed calculations have
been made for a minimum beam size of 0.3 µm.
Configuration delivering a 0.1 µm beam
The mirror quality in terms of slope errors should be exceptional. For example, for a value of ε =
0.3 µrad RMS on the KB mirror (which is the present ultimate state of the art) the distance between
the last mirror centre and the sample producing a 0.1 µm FWHM beam is of the order of q = 50 mm
(by use of formula valid for gaussian distributions):
s 2 = 0.1 µm = 2 × 2 × 2.35 × q × 0.3 µrad
(2)
It is clear that the q value of 50mm is much below the requested distance around the sample
(initially 150mm). However, it can be of interest to be able to realize this value for specific
applications for which the optics to sample distance can be reduced.
For a secondary slit width s1 = 10 µm (which is well within the performances), one obtains a
secondary source – mirror distance p = 7070 mm (with a demagnification factor for the KB q/p =
1/141). Since the maximum divergence tolerated on the sample is 1 mrad, the divergence at the exit of
the secondary slits should be kept below 7.1 µrad. One derives an emittance value of 10×7.1 µm*µrad
in both horizontal and vertical planes at the slit exit.
With an incidence angle of 2.3 mrad on both mirrors, the smallest useful length for a 0.1 µm
beam output is 22 mm.
3 – Proposed configuration: beam size 0.3µm -1µm
The separation between the last mirror edge and the sample has been fixed at 110 mm and the
divergence of the beam on the sample taken at 1 mrad.
One obtains the lay-out described in table III.
Table III : beamline lay-out
Element
Primary slits S0
Filter
Pos (mm)
10000
12000
Mirror M1
15000
Secondary slits S1
Mirror M2
Horizontal focal.
25000
32000
Mirror M3
Vertical focal.
32100
Sample
32250
Surface
tore (bender)
RT = 6510.89 m
RS = 34.558 mm
Ellipse (bender)
p = 7000 mm
q = 250 mm
Ellipse (bender)
p = 7100 mm
q = 150 mm
-
θ (°)
90
90
ϕ (°)
0
0.132
90
90
0.132
Material
Be 300 µm
Sizes x×y×z
0.5×0.5 mm²
-
Rh 800Å/Si
10×300 mm2
Rh 800Å/Si
0.01×0.01 mm²
Utile : 10×100×10 mm3
Tot : 10×120×10 mm3
Rh 800Å/Si
Utile : 10×65×5 mm3
Tot : 10×80×5 mm3
-
-
0
0.132
90
-
49
In the following, the roughness is σ = 3 Å RMS for all mirrors. The slope errors are εY = 2.5 µrad
and εX = 25 µrad RMS for the toroïdal mirror M1 and ε = 0.3 µrad RMS for the KB mirrors,
The beamline will be operated in the range 5 - 30 keV. Within this spectral range, the usual mirror
coatings are typically palladium, platinum or rhodium. The transmission of the manifold 300 µm Be
filter, toroidal mirror and KB mirrors- of the beamline is displayed in figure 3 for the three different
coatings under a fixed incidence angles value of 2.3 mrad.
Transmission (filter+toric+kB)
1.0
0.8
0.6
Rh
Pt
Pd
0.4
0.2
0
0
5
10
15
20
25
30
Energy (keV)
Figure 3 : spectral transmission of the filter-mirrors assembly
The rhodium coating is the best compromise in terms of overall efficiency on the whole energy range.
Simulations for the bending magnet source
Table IV summarizes the beam properties at the sample site for three different secondary slits aperture
Table IV : parameters FWHM of the beam on the sample with the bending magnet source
S1 : H×V
10×10 µm²
N (ph/s)
2.10×101
∆x (µm)
0.42
∆z (µm)
0.23
∆x’ (µrad)
944
∆z’ (µrad)
1020
0.68
0.59
940
1030
1.06
1.04
936
1022
1
20×30 µm²
1.13×101
2
32×55 µm²
3.03×101
2
Figures 4 to 6 display the image and profiles (integrated horizontal and vertical, spectral) of the
beam, on the sample with a secondary slit aperture of 10×10 µm².
Figure 4 : simulated beam image on the sample (s1 : 10×10 µm²)
50
14
8x10
horizontal
420 nm FWHM
vertical
230 nm FWHM
secondary slits
10×10 µm²
Intensity (ph/s/mm)
14
6x10
14
4x10
14
2x10
0
-0.50
-0.25
0
0.25
0.50
size (µm)
Figure 5 : horizontal and vertical beam profiles (s1 : 10×10 µm²)
8
10
Secondary slits : 10×10 µm²
11
Intensity (ph/s/eV)
Itot = 2.1×10
ph/s
7
10
6
10
5
10
0
5
10
15
20
25
30
Energy (keV)
Figure 6 : beam spectral distribution on the sample (s1 : 10×10 µm²)
Remark : As far as spatial coherence is concerned one should notice that the beam would be 80%
coherent in the most focused mode (0.23 mm) only for wavelength λ > 6.4 Å ( E < 2 keV), well below
the beamline energy range.
Simulations for the wiggler source
Table V summarizes the beam properties at the sample site for three different secondary slits aperture.
Table V : beam parameters FWHM on the sample for the wiggler source
S1 : H×V
10×10 µm²
20×30 µm²
32×55 µm²
N (ph/s)
3.46×1012
1.48×1013
3.71×1013
∆x (µm)
0.37
0.68
1.06
∆z (µm)
0.22
0.59
0.99
∆x’ (µrad)
944
950
944
∆z’ (µrad)
1020
1034
1035
51
Figures 7 to 9 display the image and profiles (integrated horizontal and vertical, spectral) of the
beam, on the sample with a secondary slit aperture of 10×10 µm².
Figure 7 : beam image at the sample site (s1 : 10×10 µm²)
16
1.5x10
horizontal
370 nm FWHM
vertical
220 nm FWHM
Intensity (ph/s/mm)
secondary slits
10×10 µm²
16
1.0x10
16
0.5x10
0
-0.50
-0.25
0
0.25
0.50
size (µm)
Figure 8 : horizontal and vertical beam profile on the sample (s1 : 10×10 µm²)
9
10
Secondary slits : 10×10 µm²
12
Intensity (ph/s/eV)
Itot = 3.5×10
ph/s
8
10
7
10
6
10
0
5
10
15
20
25
30
Energy (keV)
Figure 9 : spectral distribution on the sample (s1 : 10×10 µm²)
52
Monochromatic beamline operation mode
We will consider successively the cases of the bending magnet and wiggler sources for two
different monochromators : a two-crystals Si111 monochromator or a 4-crystals double channel-cut in
(+,+) configuration monochromator inserted between the secondary slits and the KB mirrors (see
figure 2). Tables VI et VII give the beam parameters on the sample for each monochromator choice
and three selected beam energies for the bending magnet source and tables VIII and IX give the same
quantities for the wiggler source.
Bending magnet:
Table VI : beam parameters FWHM with a two-crystal Si111 monochromator on a bending magnet
E (keV)
8
12.4
20
N (ph/s)
3.16×107
3.25×107
2.17×107
∆E (eV)
0.97
1.66
3.36
∆x (µm)
0.38
0.39
0.39
∆z (µm)
0.25
0.22
0.26
∆x’ (µrad)
940
940
940
∆z’ (µrad)
1030
1025
1030
Table VII : beam parameters FWHM with a four-crystal Si111 monochromator on a bending magnet
E (keV)
8
12.4
20
N (ph/s)
1.85×107
1.55×107
6.5×106
∆E (eV)
0.68
1.08
1.29
∆x (µm)
0.43
0.41
0.45
∆z (µm)
0.24
0.22
0.26
∆x’ (µrad)
940
943
945
∆z’ (µrad)
1030
1030
350
Wiggler
Table VIII : beam parameters FWHM with a two-crystal Si111 monochromator
E (keV)
8
12.4
20
N (ph/s)
1.94×108
2.21×108
1.88×108
∆E (eV)
1.04
1.60
3.19
∆x (µm)
0.36
0.35
0.41
∆z (µm)
0.26
0.26
0.23
∆x’ (µrad)
943
940
942
∆z’ (µrad)
1030
1030
1030
Table IX : beam parameters FWHM with a four-crystal Si111 monochromator
E (keV)
8
12.4
20
N (ph/s)
1.20×108
1.44×108
5.82×107
∆E (eV)
0.68
1.02
1.27
∆x (µm)
0.35
0.36
0.41
∆z (µm)
0.28
0.27
0.24
∆x’ (µrad)
942
940
942
∆z’ (µrad)
1030
1000
340
It is clear that at 20 keV, due to the narrow rocking curve width, the two-crystal configuration
delivers a higher flux at the expense of the quality of the spectral resolution since in that case, the
collimating efficiency of the four-crystal configuration is enhanced.
Remark: In order to use the monochromator properly in the energy range 5-8 keV, one has to
eliminate higher harmonics either by use of an additional mirror with proper coating or by slightly
detuning on set of crystals in the 4-crystal mode.
53
Harmonics rejection
In monochromatic mode, harmonic rejection in the 5-8 keV energy range can be achieved
by a symmetric detuning of the 2nd and 3rd crystals with respect to the symmetry plane of the
monochromator (figure 10).
θ
+δ
θ
−δ
θ
+δ
θ
−δ
Figure 10 : schematic of a detuned four-crystal monochromator
As shown in fig.10, the exit beam direction in independent on the misalignement angle δ.
The exit beam height difference h between the modes is given to the first order by relation
h ≈ 2δ(L +
G
)
sin θ
where L is the distance between the centers of crystal 2 and 3 (figure 1) and G the gap
between the two faces of each channel-cut pair Taking G = 6 mm, L = 200 mm and δ = 4.2
µrad (2.4×10-4 deg), one obtains a rejection factor of 5×10-4 at 5 keV with a vertical shift h
equal to -1.8 µm. It can be shown that the focused beam at the exit of the KB is still centered
on the sample ( independent on the δ value) with a vertical angular shift of -11.4 µrad
compared to the fully tuned case.
The rejection factors for three energies and δ = 4.2 µrad, are displayed in table X
Tableau X: harmonics rejection factor for the monochromator
E
(keV)
5
6
7
θBragg (°)
τ = I3/I1
23.296
19.243
16.409
5.3×10-4
1.1×10-4
7.8×10-5
4 – Thermal budget
Tables XI and XII give the thermal budget for the successive beamline components in
polychromatic mode for the bending magnet and the wiggler soources respectiveley. For these
calculations, the integrated energy range is 0.1 to 50 keV . The secondary slit aperture is taken at
60×60 µm² which is in any case superior to the largest aperture used on the beamline.
54
Table XI : Thermal budget in polychromatic mode on the bending magnet
Magnet
Primary slits : 500×500 µm²
Filter : Be 300 µm
Toroidal mirror
Secondary slits : 60×60 µm²
KB HFM
KB VFM
Ptrans (W)
0.65
0.57
0.44
0.16
0.07
0.017
PAbs (W)
73.6 W / mrad hor
0.08
0.11
0.28
6×10-3
1.3×10-3
∆PAbs (W/mm²)
2.6
0.32
4×10-4
56
1×10-4
2×10-4
Remark : as can be seen in the table most of the power transmitted by the secodary slits is not
intercepted by the KB mirrors
In monochromatic mode and for the same aperture of the secondary slits, at a Bragg angle θ =
23.296° which corresponds to 5 keV, one obtains an absorbed power PAbs = 159 mW on the first
crystal with an absorbed power density of 10 W/mm². For the downstream optics the calculated
absorbed powers are negligible.
Tableau XII : Thermal budget on the wiggler source
Wiggler
Primary slits : 500×500 µm²
Filter : Be 300 µm
Toroidal mirror
Secondary slits : 60×60 µm²
KB HFM
KB VFM
Ptrans (W)
28.94
26.48
18.38
1.23
0.53
0.13
PAbs (W)
3383 W / mrad hor
2.46
6.07
17.15
0.05
0.01
∆PAbs (W/mm²)
115.8
9.84
0.026
400
1×10-3
1×10-3
In monochromatic mode and the same conditions as previously described one finds PAbs = 1.23 W
on the first crystal and a power density of 72 W/mm². For the downstream optics the calculated
absorbed powers are negligible.
5 – Sample environment
A 4 circles Goniometer with a sphere of confusion as small as possible (~ 10 µm) is necessary
even if rotations are strongly prohibited during scanning XRD measurements. The sample will be
mounted on a goniometer head with z axis for sample surface positioning thanks also to an x-ray eye
camera and x-y sample stages enabling large scans up to 20 mm and smaller ones with step sizes of at
least 0.1 µm. An optical camera (or microscope) will allow a rough positioning of the illuminated
sample surface (100 µm resolution) with respect to the x-ray beam position. An accurate positioning is
then done using markers and fluorescence scans in WB mode with a classical fluorescence detector
composed of 7 elements. Diffraction patterns are recorded with a CCD 2D detector which allows real
time experiments in the millisecond range for the WB mode. Specific sample environment such as
heating/cooling and deformation set ups will be available thanks to tight collaborations between
laboratories involve in this project and also other material science beam lines such as Diffabs where
these same laboratories are also working.
55
The experimental set-up will allow adjustable detector- sample distance to evaluate the in-depth
deformation gradient by triangulation and also adjustable optics-sample distance to optimize the beam
size and/or the beam convergence in order to control the spatial and angular resolution of the setup.
Working place for sample (and experiment) preparation will be available with conventional
equipments such as an optical microscope equipped with a CCD camera for recording numerical
images on a computer where dedicated image treatment softwares will be used.
Data analysis is performed thanks to XMAS Software developed by N. Tamura at ALSLBNL. A CNRS post-doc is presently contributing for improving the software algorithms and thus the
refinement procedure which is time consuming.
3D structural microscopy is becoming a powerful tool (see publication list appendix 3 and the
figure below) and needs an additional specific instrumentation which is related mainly with an x-ray
spot absorber (micrometer wire) scan of the sample surface with a sub micrometer step for each x-y
sample stage scan step. The number of frame to be treated by the refinement software is then
dramatically increasing! This reinforces the fact that powerfull computing facilities must be available
at the beam line (Cluster with 48 nodes) for providing real time analysis during the scan.
Figure 11: Schematic illustration of the Differential Aperture X-ray Microscopy (DAXM)
technique to obtain inter- and intragranular Laue diffraction patterns from submicrometer
increments along the microbeam. DCCD is the distance from the detector to the profiler wire,
and DXR is the distance from the x-ray microbeam to the profiler wire.
The intensity change between images collected with the wire at positions a and b provides the
intensity Ia – Ib (hatched areas). The intercept of the CCD pixel/wire-edge ray and the
incident beam determines the origin of the intensity difference. B.C. Larson et al., Nature
(2002) 415, 887.
56
6 – Critical aspects
The thermal power density due to the focus beam on the optics (Monochromator, toroidal
mirror ) and slits are huge and then specific cooling have to be operated. Furthermore, the studied
samples have also to support high thermal power densities which may lead to sample degradations in
certain cases (biology for instance).
Vibration impact on focusing quality and stability is fundamental: all pumps must be outside
the Hutch and a rigid and stable system must support together the sample stage and optics.
7 –Estimated financial breakdown (k€)
Source and Optics
Financial contribution in case of wiggler (total 400 k€) :
Primary slits in case of bending magnet source
Mirror (chamber, mirror, cooling system):
KB optics (bimorph or mechanical benders)
Monochromator (4-Crystals):
110 k€
30 k€
200 k€
200 k€
300 k€
Experimental setups
Diffractometer (4-circles):
Detector 2D - CCD camera:
Fluorescence detector (7 elements):
Equipments for diffractometer and sample environment:
(slits, X-ray eye camera, microscope, etc;)
300 k€
300 k€
160 k€
100 k€
Infrastructure
Hutches:
Fluids, electricity, control room, PSS, network, etc. :
Air conditioning:
Vacuum:
Control / command :
Tubes / Be windows / shutter :
Diagnostics (XBPM / monitors) :
TOTAL COAST Bending Magnet / Wiggler:
230 k€
250 k€
100 k€
150 k€
120 k€
70 k€
60 k€
2570 / 2650 k€
57
APPENDIX 1: WORKING GROUPS
GROUP I
MICROELECTRONICS
G. Rolland (CEA/LETI), O. Sicardi (CEA/DSM),
& R. Bisaro (Thales)
MICROSYSTEMS
A. Bosseboeuf (IEF-Orsay)
GROUP II
METALLURGY AND MECHANICS
O. Castelnau (LPMTM-Villetaneuse)
& J-L. Lebrun (ENSAM-Angers)
GROUPE III MINERALOGY, PLANETARY & EARTH SCIENCES
B. Devouard (MV-Clermont-Ferrand)
ART AND ARCHEOLOGY
E. Dooryhée (LC-Grenoble)
GROUPE IV LIFE SCIENCES AND SOFT CONDENSED MATTER
A. Buléon (INRA-Nantes), F. Briki (LPS-Orsay)
Ph. Goudeau (LMP-Poitiers) and O. Thomas (TECSEN-Marseille),
coordinators
58
APPENDIX 2: CNRS POST-DOC 2005-2006
Micro X-Ray Diffraction mapping: instrumental development at the ALSBerkeley for the study of mechanical properties of low dimensional materials.
Research project:
General context: Mechanical properties of low dimensional materials generate a growing interest
in the scientific community. In a general way « smaller is stronger », materials with small dimensions
(typically less than one micron) may accept higher stress magnitude than their bulk counter part.
Small-dimension structures are therefore interesting systems for the study of mechanical stress effect
on physical properties (ex: magnetic, electronic…). On the other hand, these stresses are responsible
for damage, functional anomalies (electromigration, failure, decohesion and buckling, hillocks and
void formation …) which are necessary to avoid for improving micro systems reliability. In thin films,
nanostructured or not, large strain gradients exist near the free edges or at grain boundaries and
interfaces. The study of local strain is thus a necessity for improving our understanding of the
micromechanics of these structures. This research effort on the mechanics of nanostructures is very
important in the United States (W. Nix and B. Clemens at Stanford, C. Thompson and S. Suresh at
MIT, F. Spaepen at Harvard, S. Baker at Cornell …). In France, two laboratories are more particularly
involved in this thematic: the LMP at Poitiers and the TECSEN at Marseille.
Scientific context of the postdoctoral training: Mechanical properties of nanostructured materials
can not be explained by using what is generally known for mechanical behaviour of bulk materials and
are yet not well understood. Till now, most of measurements done for example in nanostructured thin
films concern the average response of the sample to a mechanical solicitation. An understanding of the
mechanical property of these materials needs on the contrary a more accurate knowledge of the stress
distribution and thus requires local measurements. Indeed in such objects, and contrarily to what
happens in a bulk material, the role of interfaces, surfaces or grain boundaries becomes preponderant
as the characteristic size reaches a few nanometers.
X-ray Diffraction (XRD) strain analysis of the lattice at the required scale (sub-micron)
necessarily involves the use of both a synchrotron radiation source allowing to work either with white
(5-25 KeV) or monochromatic x-ray beam, and a 2D detector for collecting diffraction data at the
same time along 2Θ and χ axis. In fact, sample rotations are prohibited since the expected confusion
sphere for a 4-circles goniometer cannot be better than 10 microns. The white beam X-ray
microdiffraction technique has not been implemented yet in Europe whereas remarkable developments
in this field are in progress over the Atlantic. In particular, results recently obtained on beamline 7.3.3
at the Advanced Light Source (ALS) at the Lawrence Berkeley National Laboratory (LBNL) allowed
for significant achievements [1-3]: very strong stress heterogeneities have been detected in metallic
thin films at a sub-micron scale. The awareness, in France, of the interest of such a tool has lead to the
white beam micro-XRD project on the CRG BM32 at ESRF with the financial support of CNRS and
CEA organisms. The scientific thematic of this postdoctoral training is directly linked with this ESRF
project and more largely in the development of such a beamline at SOLEIL in France.
Scientific objectives of the postdoctoral training: The post-doc will develop his research project
in agreement with scientific activity of the two laboratories (P. Goudeau at LMP, O. Thomas at
TECSEN). One of the important goals of this project will be the achievement of a methodology for
studying local stress fields in nanostructured materials where stress field heterogeneity is an important
59
factor. One can notice for example strain distribution in polycrystalline thin films in relation with
elastic or plastic anisotropy (metals, silicides of transition metals…). The association reactivitystresses is also an area where the access to local stresses is important.
Data analysis is strongly linked with instrumental development. The post-doc researcher will
be supervised at the ALS by Nobumichi Tamura. In that way, he will participate to user’s support on
beamlines for which N. Tamura has the responsibility and will develop his instrumental and software
activities considering the two following points:
1) 3D analysis of materials following the methodology developed by B. Larson and G. Ice at
the APS [4]. Actually, only the in-plane resolution is available at the ALS. In depth analysis in layers
is necessary for determining gradients, for example, in the case of thin film buckling or for layers
which have reacted.
2) Stress and strain tensor determination for monochromatic beam experiments from
refinement of all the information collected by 2D detectors. Indeed, this analysis is partial or selective
[5] and an analysis software that takes into account the collected diffraction data as a whole, does not
exist at the moment.
These developments will reinforce the know-how and the competence of the ALS in this field. There
will be the result of an efficient and long-term fruitful collaboration between the CNRS and the
LBNL. This close relation related to this post-doc, will give the opportunity, in a near future, for the
building of this type of beamline in France (and in Europe!). The LBNL and the ALS have one of the
most prolific programs in the field of microdiffraction in materials science. Benefits for research in
France related to this close collaboration would be considerable.
References
[1] Phillips M. A. , Spolenak R. , Tamura N. , Brown W. L. , MacDowell A. A. , Celestre R. S. , Padmore H. A.
, Batterman B. W. , Arzt E. , Patel J. R., X-ray microdiffraction: local stress distributions in polycrystalline
and epitaxial thin films, Microelectronic engineering 75 (1) {2004) 117.
[2] Barabash R. I. , Ice G. E. , Tamura N. , Valek B. C. , Bravman J. C. , Spolenak R. , Patel J. R., Quantitative
characterization of electromigration-induced plastic deformation in Al(0.5wt%Cu) interconnect,
Microelectronic engineering 75 (1) (2004) 24.
[3] Caldwell W. A. , Tamura N. , Celestre R. S. , MacDowell A. A. , Padmore H. A. , Geballe T. H. , Koster G. ,
Batterman B. W. , Patel J. R. , Shear at twin domain boundaries in YBa2Cu3O7-x, Physical review letters
92 (21) (2004).
[4] Yang Wenge, Larson B.C., Pharr G.M., Ice G.E., Budai J.D., Tischler J.Z., Liu Wenjun, Deformation
microstructure under microindents in single-crystal Cu using three-dimensional x-ray structural
microscopy, J. Mater. Res. 19 (1) (2004) 66.
[5] Gelfi M., Bontempi E., Roberti R., Depero L.E., X-ray diffraction Debye Ring Analysis for Stress
measurement (DRAST): a new method to evaluate residual stresses, Acta Materialia 52 (2004) 583.
Profile of the candidate:
PhD in materials science: inorganic thin films, structural analysis by XRD.
Instrumentation:A synchrotron radiation experience in the field of structural analysis is strongly
desired. Knowledge on intrinsic mechanical properties of thin films and more particularly concerning
elasticity and stresses would be greatly appreciated.
Simulation and computing: the researcher will interact with Nobumichi Tamura for the XMAS
software development for monochromatic data analysis and 3D investigations (IDL and Fortran
environments).
60
APPENDIX 3: REFERENCES FOR WB µ-XRD EXPERIMENTS
2D
[1] J. S. Chung, N. Tamura, G. E. Ice, B.C. Larson, J. D. Budai, W. Lowe, X-ray Microbeam
Measurement of Local Texture and Strain in Metals, Mat. Res. Soc. Symp. Proc 563, 169 (1999).
[2] N. Tamura, J.-S. Chung, G. E. Ice, B. C. Larson, J. D. Budai, J. Z. Tischler, M. Yoon, E. L.
Williams, W. P. Lowe, Strain and Texture in Al-Interconnect Wires Measured by X-ray Microbeam
Diffraction, Mat. Res. Soc. Symp. Proc 563, 175 (1999).
[3] N. Tamura, J. – S. Chung, G. E. Ice, B. C. Larson, J. D. Budai, J. Z. Tischler, M. Yoon, E. L.
Williams, W. P. Lowe, Strain and texture in Al-interconnect wires measured by X-ray microbeam
diffraction, Mat. Res. Soc. Symp. Proc. 563, 175 (1999).
[4] N. Tamura, B. C. Valek, R. Spolenak, A. A. MacDowell, R. S. Celestre, H.A.Padmore, W. L.
Brown, T. Marieb, J. C. Bravman, B. W. Batterman, J. R. Patel, Grain Orientation and Strain
Measurements in Sub-Micron wide Passivated Individual Aluminum Test Structures, Mat. Res. Soc.
Symp. Proc. 612, D8.8.1 (2000).
[5] R. Spolenak, D. L. Barr, M. E. Gross, K. Evans-Lutterodt, W. L. Brown, N. Tamura, A. A.
MacDowell, R. S. Celestre, H. A. Padmore, B. C. Valek, J. C. Bravman, P. Flinn, T. Marieb, R. R.
Keller, B. W. Batterman, J. R. Patel, Microtexture ans strain in electroplated copper interconnects,
Mat. Res. Soc. Symp. Proc. 612, D10.3.1 (2000).
[6] B. C. Valek, N. Tamura, R. Spolenak, A. A. MacDowell, R. S. Celestre, H. A. Padmore, J. C.
Bravman, W. L. Brown, B. M. Batterman, J. R. Patel, Local microstructure and stress in Al(Cu) thin
film structures studied by x-ray Microdiffraction, Mat. Res. Soc. Symp. Proc. 673, 771 (2001).
[7] R. Spolenak, N. Tamura, B. C. Valek, A. A. MacDowell, H. A. Padmore, W. L. Brown, T. Marieb,
B. W. Batterman, J. R. Patel, High resolution Microdiffraction studies using synchrotron radiation, in
6th International Workshop on Stress Induced Phenomena in Metallization, AIP conference
proceeding 612, S. P. Baker, M. A. Korhonen, E. Arzt, P. S. Ho Editors (2001).
[8] A.A. MacDowell, R.S.Celestre, N. Tamura, R. Spolenak, B. C. Valek, W.L. Brown, J.C. Bravman,
H.A. Padmore, B. W. Batterman, J. R. Patel, Submicron X-ray diffraction, Nuclear Instruments &
Methods in Physics Research A 467-468, 936 (2001).
[9] C. U. Jung, J. Y. Kim, P. Chowdhury, K. H. P. Kim, S.-I. Lee, D. S. Koh, N. Tamura, W. A.
Caldwell, J. R. Patel, Microstructure and pinning properties of hexagonal-disc shaped single
crystalline MgB2, Physical Review B 66, 18 (2002).
[10] N. Tamura, A.A. Mac Dowell, R. S. Celestre, H. A. Padmore, B. Valek, J. C. Bravman, R.
Spolenak, W. L. Brown, T. Marieb, H. Fujimoto, B. W. Batterman, J. R. Patel, High spatial resolution
grain orientation and strain mapping in thin films using polychromatic submicron x-ray diffraction,
Applied Physics Letters 80, 3724 (2002).
[11] B. C. Valek, J. C. Bravman, N. Tamura, A. A. MacDowell, R. S. Celestre, H. A. Padmore, R.
Spolenak, W. L. Brown, B. W. Batterman, J. R. Patel, Electromigration-induced plastic deformation
in passivated metal lines, Applied Physics Letters 81, 4168 (2002).
[12] N. Tamura, R. S. Celestre, A. A. Mac Dowell, H. A. Padmore, R. Spolenak, B. C. Valek, N. M.
Chang, A. Manceau, J. R. Patel, Submicron x-ray diffraction ans its applications to problems in
materials and environmental science, Review of Scientific Instruments 73, 1369 (2002).
[13] W. J. Choi, T. Y. Lee, K. N. Tu, N. Tamura, R. S. Celestre, A. A. MacDowell, Y. Y. Bong, L.
Nguyen, G. T. T. Sheng, Structure and kinetics of Sn whiskers growth on Pb-free solder finish, 52nd
Electronic component & technology conference proceedings IEE, 628 (2002).
61
[14] R. I. Barabash, G. E. Ice, N. Tamura, J. R. Patel, B. C. Valek, J. C. Bravman, R. Spolenak,
Spatially resolved characterization of electromigration-induced plastic deformation in Al (5 at % Cu)
interconnect, Mater. Res. Soc. Symp. Proc. 738, G13.1.1 (2003).
[15] R. I. Barabash, N. Tamura, B. C. Valek, R. Spolenak, J. C. Bravman, G. E. Ice, J. R. Patel,
Quantitative characterization of Dislocation structure coupled with electromigration in a passivated
Al (0.5 wt% Cu) interconnecst, Mater. Res. Soc. Symp. Proc. 766, 107 (2003).
[16] B. C. Valek, N. Tamura, R. Spolenak, W. A. Caldwell, A. A. MacDowell, R. S. Celestre, H. A.
Padmore, J. C. Bravman, B. W. Batterman, W. D. Nix, J. R. Patel, Early stage of plastic deformation
in thin films undergoing electromigration, Journal of Applied Physics 94, 3757 (2003).
[17] N. Tamura, A. A. MacDowell, R. Spolenak, B. C. Valek, J. C. Bravman, W. L. Brown, R. S.
Celestre, H. A Padmore, B.W. Batterman, J. R. Patel, Scanning X-ray microdiffraction with
submicrometer white beam for strain/stress and orientation mapping in thin films, J. Synchrotron Rad.
10, 137 (2003).
[18] R. Spolenak, W. L. Brown, N. Tamura, A. A. MacDowell, R. S. Celestre, H. A. Padmore, B.
Valek, J.C. Bravman, T. Marieb, H. Fujimoto, B.W. Batterman, J. R. Patel, Local Plasticity of Al Thin
Films as Revealed by X-Ray Microdiffraction, Physical Review Letters 90, 096102-1 (2003).
[19] R. I. Barabash, G. E. Ice, N. Tamura, B. C. Valek, J. C. Bravman, R. Spolenak, J. R. Patel,
Quantitative Analysis of Dislocation Arrangements Induced by Electromigration in passivated Al (0.5
wt% Cu) Interconnect, Journal of Applied Physics 93, 5701 (2003).
[20] R. C. Rogan, N. Tamura, G. A. Swift, E. Ustuntag, Direct measurement of triaxial strain fields
around ferroelestric domains using x-ray microdiffraction, Nature Materials 2, 379 (2003).
[21] T. J. Richardson, B. Farangis, J. L. Slack, P. Nachimuthu, R. Perera, N. Tamura, M. Rubin, X-ray
absorption spectroscopy of transition metal-magnesium hydride thin films, Journal of alloys and
compounds 356-357, 204 (2003).
[22] B. C. Valek, X-ray Microdiffraction studies of mechanical behaviour and electromigration in thin
film structures, PhD thesis, Stanford, USA (2003)
[23] S. Rigo, P. Goudeau, J.-M. Desmarres, T. Masri, J.-A. Petit and P. Schmitt, Correlation between
X-ray Microdiffraction and a developed analytical model to measure the residual stresses in
suspended structures in MEMS, Microelectronics Reliability 43, 1963 (2003).
[24] D. I. Savytskii, D. M. Trots, L. O. Vasylechko, N. Tamura, M. Berkowski, Twinning in
La0.95Sr0.05Ga0.9Mg0.1O2.92 crystals studied by white beam (Laue) X-ray Microdiffraction, Journal of
Applied Crystallography 36, 1197 (2003).
[25] W. J. Choi, T. Y. Lee, K. N. Tu, N. Tamura, R. S. Celestre, A. A. MacDowell, Y. Y. Bong, L.
Nguyen, Tin whiskers studied by synchrotron radiation scanning X-ray microdiffraction, Acta
Materialia 51, 6253 (2003).
[26] K. H. P. Kim, C. U. Jung, B. W. Kang, K. H. Kim, H. S. Lee, S. I. Lee, N. Tamura, W. A.
Caldwell, W. D. Nix, J. R. Patel, Microstructure and superconductivity of MgB2 single crystals,
Current Applied Physics 4, 272 (2004).
[27] A. S. Budiman, N. Tamura, B. C. Valek, K. Gadre, J. Maiz, R. Spolenak, W. A. Caldwell, W. D.
Nix, J. R. Patel, Unexpected mode of plastic deformation in Cu damascene lines undergoing
electromigration, Mater. Res. Soc. Symp. Proc. 812, F7.3.1 (2004).
[28] R. I. Barabash, G. E. Ice, N. Tamura, B. C. Valek, R. Spolenak, J. C. Bravman, J. R. Patel,
Coupling between precipitation and plastic deformation during electromigration in passivated Al (0.5
at % Cu) interconnect, Mater. Res. Soc. Symp. Proc. 812, F7.4.1 (2004).
[29] W. A. Caldwell, N. Tamura, R. S. Celestre, A. A. MacDowell, H. A. Padmore, T. H. Geballe, G.
Koster, B. W. Batterman, J. R. Patel, Shear at twin domain boundaries in YBa2Cu3O7-x, Physical
Review Letters 92, 21 (2004).
62
[30]M.A. Phillips, R. Spolenak, N. Tamura, W.L. Brown, A.A. MacDowell, R.S. Celestre, H.A.
Padmore, B.W. Batterman, E. Arzt, J.R. Patel, X-ray microdiffraction: local stress distributions in
polycrystalline and epitaxial thin films, Microelectronic Engineering 75, 117 (2004).
[31] R. I. Barabash, G. E. Ice, N. Tamura, B. C. Valek, J. C. Bravman, R. Spolenak, J. R. Patel,
Quantitative characterization of electromigration-induced plastic deformation in Al (0.5 at % Cu)
interconnect, Microelectronic Engineering 75, 24 (2004).
[32] H. D. Joo, K. H. Kim, C. W. Bark, Y. M. Koo, N. Tamura, In situ synchrotron X-ray
microdiffraction study of lattice rotation in polycrystalline materials during uniaxial deformations,
Synchrotron Radiation Conference Proceedings 705, 1094 (2004).
[33] A. T. Wu, K. N. Tu, J. R. Lloyd, N. Tamura, B. C. Valek, C. R. Kao, Electromigration-induced
microstructure evolution in tin studied by synchrotron x-ray microdiffraction, Applied Physics Letters
85, 2490 (2004).
[34] H. D. Joo, J.S. Kim, K. H. Kim, N. Tamura, Y. M. Koo, In situ synchrotron X-ray
microdiffraction study of deformation behavior in polycrystalline coppers during uniaxial
deformations, Scripta Materiala 51, 1183 (2004).
[35] N. Tamura, H. A. Padmore, J. R. Patel, High spatial resolution stress measurements using
synchrotron based scanning X-ray microdiffraction with white or monochromatic beam, Materials
Science & Engineering A 399, 92 (2005).
[36] R.I. Barabash, G.E. Ice, W. Liu, S. Einfeldt, D. Hommel, A.M. Roskowski, R.F. Davis,
Characterization of stress relaxation, dislocations and crystallographic tilt via x-ray Microdiffraction
in GaN (0001) layers grown by maskless pendeo-epitaxy, Mater. Res. Soc. Symp. Proc. 875, 04.9.1
(2005).
[37] P. Goudeau, N. Tamura, B. Lavelle, S. Rigo, T. Masri, A. Bosseboeuf, T. Sarnet, J.-A. Petit, J.-M.
Desmarres, X-ray diffraction characterization of suspended structures for MEMS applications, Mater.
Res. Soc. Symp. Proc. 875, O4.11.1 (2005).
[38] P. Goudeau, N. Tamura, G. Parry, J. Colin, C. Coupeau, F. Cleymand, H. Padmore, Strain
mapping on gold thin film buckling and silicon blistering, Mater. Res. Soc. Symp. Proc. 875, O10.4.1
(2005).
3D
(X-ray structural microscopy)
[1] G. E. Ice, B. C. Larson, 3D X-ray crystal microscope, Advanced Engineering Materials 2, 643
(2000).
[2] R. Barabash, G. E. Ice, B. C. Larson, G. R. Pharr, K. S. Chung, W. Yang, White microbeam
diffraction from distorted crystals, Applied Physics Letters 79, 749 (2001).
[3] B. C. Larson, W. Yang, G. E. Ice, J. D. Budai, J. Z. Tischler, Three-dimensional X-ray structural
microscopy with submicrometre resolution, Nature 415, 887 (2002).
[4] R. I. Barabash, G. E. Ice, B. C. Larson, W. Yang, Application of white x-ray microbeams for the
analysis of dislocation structures, Review of Scientific Instruments 73, 1652 (2002).
[5] J. Miao, T. Ishikawa, B. Johnson, E. H. Anderson, B. Lai, K. O. Hodgon, High resolution 3D Xray diffraction microscopy, Physical Review Letters 89, 088303 (2002).
[6] G. Schmahl, Focus on X-ray microscopy, special issue of Synchrotron Radiation News 16 (3)
(2003).
[7] G. E. Ice, W. Liu, B. C. Larson, F. J. Walker, Application of the 3D X-ray crystal microscope to
study mesoscale structure of materials, Mat. Res. Symp. Proc. 779, W5.36.1 (2003).
[8] R. I. Barabash, G. E. Ice, F. J. Walker, Quantitative Microdiffraction from deformed crystals with
unpaired dislocations and dislocation walls, Journal of Applied Physics 93, 1457 (2003).
63
[9] W. Yang, B. C. Larson, G. M. Pharr, G. E. Ice, J. Z. Tischler, J. D. Budai, W. Liu, X-ray
microbeam investigation of deformation microstructure in microindented Cu, Mat. Res. Symp. Proc.
779, W5.34.1 (2003).
[10] S. Marchesini, H. He, H. N. Chapman, S. P. Hau-Riege, A. Noy, M. R. Howells, U. Welerstall, J.
C. H. Spence, X-ray image reconstruction from a diffraction pattern alone, Phys. Rev. B 68, 140101
(2003).
[11] W. Liu, G. E. Ice, B. C. Larson, W. Yang, J. Z. Tischler, J. D. Dubai, The three-dimensional Xray crystal microscope: a new tool for materials cheracterization, Metallurgical and Materials
Transactions A 35, 1963 (2004).
[12] O. M. Barabash, J. A. Horton, S. S. Babu, J. M. Vitek, S. A. David, J. W. Park, G. E. Ice, R. I.
Barabash, Evolution of dislocation structure in the heat affected zone of a nickel-based single crystal,
Journal of Applied Physics 96, 3673 (2004).
[13] W. Yang, B. Larson, G. Pharr, G. Ice, J. Dubai, J. Tishler, W. Liu, Deformation microstructure
under microindents in single-crystal Cu using three-dimentional x-ray structural microscopy, Journal
of Materials Research 19, 66 (2004).
[14] W. Yang, B. C. Larson, J. Z. Tishler, G. E. Ice, J. D. Dubai, W. Liu, Differential-aperture X-ray
structural microscopy: a submicron-resolution three-dimensional probe of local microstructure and
strain, Micron 35, 431 (2004).
[15] B. C. Larson, B. Lengeler, High-resolution three-dimensional x-ray microscopy, special issue of
MRS Bulletin 29 (3) (2004).
[16] J. Baruchel, A. Kvick, Synchrotron radiation imaging and diffraction for industrial applications,
Europhysics News March/April 50 (2004).
[17] B. C. Larson, W. Yang, Perspective on submicron-resolution three-dimensional x-ray structural
microscopy to address mesoscale materials microstructure and evolution issues, Mater. Res. Symp.
Proc. 875, BB1.1.1 (2005).
[18] R. I. Barabash, G. E. Ice, W. Liu, S. Einfeldt, A. M. Roskovski, R. F. Davis, Local strain, defects
and crystallographic tilt in GaN (0001) layers grown by maskless pendeo-epitaxy from X-ray
Microdiffraction, Journal of Applied Physics 97, 013504 (2005).
[19] G. E. Ice, B. C. Larson, W. Yang, J. D. Budai, J. Z. Tischler, J. W. L. Pang, R. I. Barabash, W.
Liu, Polychromatic X-ray Microdiffraction studies of mesoscale structure and dynamics, J. of
Synchrotron Rad. 12, 155 (2005).
[20] W. Liua, G. E. Ice, B. C. Larson, W. Yang, J. Z. Tischler, Nondestructive three-dimensional
characterization of grain boundaries by X-ray crystal microscopy, Ultramicroscopy 103, 199 (2005).
[21] R. I. Barabash, G. E. Ice, W. Liu, S. Einfeldt, D. Hommel, A. M. Roskovski, R. F. Davis, White
X-ray microbeam analysis of starin and crystallographic tilt in GaN layers grown by maskless
pendeoepitaxy, Physica Status Solidi A 202, 732 (2005).
[22] G. E. Ice, R. I. Barabash, F. J. Walker, Characterization of nano and meso scale deformation
structures with intense X-ray synchrotron sources, Composites B 36, 271 (2005).
[23] G. E. Ice, B. C. Larson, J. Z. Tishcler, W. Liu, W. Yang, X-ray microbeam measurements of
subgrain stress distributions in polycrystalline materials, Materials Science & Engineering A 399, 43
(2005).
[24] R. I. Barabash, G. E. Ice, J. W. L. Pang, Gradient of geometrically necessary dislocations from
white beam microdiffraction, Materials Science & Engineering A 400-401, 125 (2005).
64
Conferences and SR web sites (experiments and SR activity reports)
7th International conference on Synchrotron radiation instrumentation, SRI 2000, Berlin, Germany, 2428 August 2000. Proceeding published in Nuclear Instruments & Methods in Physics Research A 467468 (2001).
Biological applications of x-ray microbeams, Workshop held at Argonne National laboratory (2001).
Meeting report from B. Lai, J. Maser, T. Paunesku, G. E. Woloshak in Synchrotron Radiation News
15, 20 (2002).
X-ray Microdiffraction, symposium at the IUCR meeting, Geneva, Switzerland, August 2002.
Application of X-ray Microdiffraction to materials and environmental sciences, Workshop held at
ALS Berkeley, USA during the User’s meeting, October 2002.
Frontiers of X-ray micro and nano beam diffraction: emerging techniques and applications, Materials
Science & Technology conference, Chicago, USA, November 2003.
Measurement and Interpretation of Internal/Residual Stresses, Symposium at the 2003 TMS annual
meeting, San Diego, USA, March 2003 – Proceedings published in Materials Science and
Engineering: A, Volume 399, Issues 1-2, Pages 1-394 (15 June 2005), Edited by B.Kad, C.S. Hartley
and M. Bourke.
Probing mechanical deformation and failure via synchrotron X-rays, joint SSRL-ALS workshop
during the SSRL’s 30th annual User’s Meeting, Stanford, USA, October 2003. Meeting report from A.
Mehta in Synchrotron Radiation News 17, 23 (2004).
Nanoprobes for nanosciences, NSLS 2004 Annual User’s Meeting Workshop. Meeting report from C.
Sanchez-Hanke, P. Sutter, published in Synchrotron Radiation News 17, 25 (2004).
http://xraysweb.lbl.gov/microdif/index.htm (ALS 7.3.3)
http://www.uni.aps.anl.gov/microdiff/ (APS UNICAT)