Jean SusiniEuropean Synchrotron Radiation FacilityBP 220, 38043 Grenoble Cedex, France

(susini@esrf.fr)

Part IIPart IIntroduction

to synchrotron radiation

Instruments&

Methods

Mostly Illustrated by examples from the ESRF

after W.C. RöntgenÜber eine neue art von Strahlen.

Phys.-Med. Ges., Würzburg, 137, (1895)English translation in Nature 53, (1996)

“... The refractive index.... cannot be more than 1.05 at most.... X-rays cannot be concentrated by lenses….”

“... Photographic plates and film are ”susceptible to x-rays”, providing a valuable means of recording the effects...”

“... Detection of interference phenomena has been tried without success, perhaps only because of their feeble intensity...”

New X-ray sources 3rd generation synchrotron sources

brilliance, coherence, polarisation

New X-ray detectors X-ray imaging X-ray spectrometry X-ray spectroscopy

New X-ray optics high energy resolution monochromator (10-7<∆E/E<10-4) new X-ray lenses (sub-µm…sub-50nm)

PART IIntroduction to synchrotron radiation

1. Origin and physics

2. Synchrotron radiation facilities

3. Historical evolution

4. Three forms of synchrotron radiation

from the Crab Nebula to Kandinsky

3 colour composite of the Crab NebulaNovember 1999

• The Crab Nebula is the remnant of the explosion of a massive star

• 7000 light-years

Credit: ESA, NASA, J. Hester & A. Loll, Arizona State University

Synchrotron radiation is one of the most important emission process in astrophysics

• X-ray synchrotron emission

• Visible emission

• Radio emission

Hester et al., 2002, Arizona State University

luminous regionswhen λ

• Synchrotron radiation is electromagnetic energy emitted by charged particles(e.g., electrons and ions) that are moving at speeds close to that of light when their paths are altered, as by a magnetic field.

• It is so called because particles moving at such speeds in particle accelerator that is known as a synchrotron produce electromagnetic radiation of this sort.

orbit

Centripetalacceleration

Classical case

v << corbit

Relativist case

v ~ c

Isotropic emission Emission concentrated within a narrow forward cone

2mcEe=γ

ψ=1/γ

Ee = 6 GeV (ESRF) mc2 = 511keV

ψ= 10-4 rad = a few 10-3 deg

Particlephysics

First particleaccelerators

Particleswith more and more

energy

bigger and bigger machines

1930

SR was considered a nuisance by particle

physicists

Particlephysics

First particleaccelerators

Particleswith more and more

energy

bigger and bigger machines

1930

First observationof synchrotronradiation

1947

First observation of synchrotron radiation at General Electric (USA).

SR used as a parasitic mode

Particlephysics

First particleaccelerators

Particleswith more and more

energy

bigger and bigger machines

1930

Synchrotron radiation

First observationof synchrotronradiation

Construction of the first“dedicated”machines

1947

1980

http://www.lightsources.org

DIAMOND (UK)SOLEIL (F)

ESRF (F)

ALBA (SP)

PETRA-III (D)

http://www.lightsources.org

APS (Argonne)

http://www.lightsources.org

SPRING8 - Japan

Year1900 1920 1940 1960 1980 2000 2020 2040

105

1010

1015

1020

1025

1030

1035

X-ray tubes

4th generation FELs

3rd generation

2nd generation

1st generationSynchrotron sources

planned

current

parasitic

dedicatedlow emittance

undulator

wiggler

photons/s/mm2/mrad2/0.1%BWBrilliance or Brightness (flux density in phase space) is an invariant quantity in statistical mechanics, so that no optical technique can improve it.

[Photons/sec]

[mm]2 [mrad]2 [0.1% bandwidth]

BendingMagnet

InsertionDevices

• Wiggler• Undulator

mBeEc 2

3 2γ=

)()(665.0)( 2 Τ= BGeVEkeVE ec

)(19572 GeVEmcE

ee ==γ

Ec

In a wiggler or an undulator, electrons travel through a periodic magneticstructure.

The magnetic field B varies sinusoidallyand is in the vertical direction:

=

u

zBzBλπ2cos)( 0

In a wiggler or an undulator, electrons travel through a periodic magneticstructure.

The magnetic field B varies sinusoidallyand is in the vertical direction:

=

u

zBzBλπ2cos)( 0

• Electron motion is also sinusoidal and lies in the horizontal plane. An important parameter characterizing the electron motion is characterized by the deflection parameter K

• The maximum angular deflection of the orbit is Κ/γ

• K >> 1 Wiggler regimeradiation from different parts of the electron trajectory adds incoherently

→ interference effects are less important

• K < 1 Undulator regime radiation from different periods interferes coherently

→ strong interference phenomena

K=0.934 λu [cm] B0 [T]

)2

1(2

2

21Ku +=

γλλ

)2

1)((

)(949.0)( 2

2

Kcm

GeVEkeVEu

e

+=

λ

On-axis

N1

=∆λλ

Fundamental + harmonics

To tweak (or to scan) energy:• E = Fct [K]

• K = Fct [B(z)]

• B(z) = Fct [gap]

To tweak (or to scan) energy:• E = Fct [K]

• K = Fct [B(z)]

• B(z) = Fct [gap]

In vacuum undulator

Revolver undulator

From “Introduction to Synchrotron Radiation”, D. Attwood, Univ. California, Berkeley

],[ 2 IEFctBBM ≈

BMwiggler BNB ×≈ 2

BMundulator BNB ×≈ 2

On-axis

Horizontal linear polarisation

Control of polarisation

Horizontal linear polarisation

ESRF : 844m circumference storage ring

1 relativistic electron ~ 2.85 µsec/lap

Number of bunches 992 870 24x8+1 16 4

Maximum current [mA] 200 200 200 90 40

Rms bunch length [ps] 20 20 25 48 55

Uniform 7/8+1 24*8+1 16 Bunch 4 BunchFilling patterns

High speed shopper (ID09)

The ESRF case

Brightness• 10+22 ph/sec/mrad2/mm2 (10+11 higher than conventional sources)

Small source and highly collimated beam• ~ 10µm and 10µrad

Broad emission spectrum: wavelength tunability• 0.1eV < E < 100keV or 1.2µm < λ < 0.01Å

Polarized radiation• 100% linear or circular or elliptical

Pulsed radiation• 50 10-12 seconds pulses every 10-9 seconds

Power • several kW total power, several 100 W/mm2 power density.

High degree of coherence

http://www.synchrotron-soleil.fr/

Optics hutch

Experimental hutch

Control cabin

Strahlenlinien (beamline)

1866-1944

PART II

Instruments & MethodsFrom Toyota to Jurassic Park

1. Beamline instrumentation

2. X-ray Fluorescence

3. X-ray spectroscopy

4. X-ray imaging

X-ray Diffraction and Protein crystallography : lectures 19-21

Optics cabin

Experiments cabin

Control room

Optics cabin

Experiments cabin

Control room

• Power (heat load) management• Photon beam steering and collimation / focusing• Select / scan photon energy

White beams:• Total emitted power : > 1 kW• Beam size (at 20 m): ~ a few mm2

Monochromatic X-ray beams:• Typical energy bandwidth (∆E/E): ~ 10-4 (a few eV @ 20keV) – 10-8

• Photon flux (∆E/E = 10-4): ~ 1013 - 1014 ph/sec• Focused beam size: ~ µm – 0.05µm

Optics cabin

Experiments cabin

Control room

• Precision mechanics (µm, µrad) almost everywhere • Remote control is mandatory• Large number of actuators (motors, piezoelectric devices)• Highly specialized sample environments• Customized detection scheme

Optics cabin

Experiments cabin

Control room

• Distributed system• Several global and local networks• Centralized data center (CPU & Storage)• Control strategy are SR facility specific!!

Management of the large variety of instruments

Structureof Materials

Electronic Structure& Magnetism

Dynamics & Extreme Conditions

Structural Biology

X-rayImaging

Structure of Soft Matter

32 public beamlines+

8 CRGs*

* Collaborating Research Group

Photo-emissionFluorescence

Elastic scattering Inelastic scattering

TransmissionAbsorptionIncident

photonSample

X-RayFluorescence

X-ray spectroscopy

X-rayDiffraction & scattering

InfraredFTIR-spectroscopy

• Composition• Quantification• Trace element mapping

• Short range structure• Electronic structure • Oxidation/speciation mapping• Molecular groups & structure

• High S/N for spectroscopy• Functional group mapping

• Long range structure• Crystal orientation mapping• Stress/strain/texture mapping

Phase contrast X-ray imaging

• 2D/3D Morphology• High resolution• Density mapping

SpecificSample environments

Chemistry12%

Electronic & Magnetic Properties

12%

Crystals &Ordered Structures

10%

Disordered Systems4%

Applied Materials, Engineering

10%Environment & Culture

7%

Macromolecular Crystallography

15%

Medicine4%

Methods & Instrumentation

2%

Soft Condensed Matter10%

Surfaces & Interfaces10%

Other: Training, feasibility tests,

proprietary research4%

Shifts delivered for Experiments, 2010

The ESRF case

Bragg’s law: 2 d sinθ = nλ

λ : wavelengthθ : incident angled : distance between 2 atomic plansn : diffraction order

First X-ray diagramme by Laue in 1912.

Crystal

X-ray beam

40

Diffraction pattern

Electron density map

3D structure

Proteincrystallisation

Blue-tonguevirus

Yeast prion Ribosome

Nucleosome

See lectures this afternoon

KB mirrors

Samplestage

Video microscopeEDSXRF

2D detectorXRD

2D detectorimaging

Element specific

Co-localization

Quantification

X-rayKen

ergy

continuum

ML

Photo-electroncontinuum

ML

K

KαKβ

Eexc

Energy dispersivedetector

energy

Inte

nsity

Wide energy spectrum (1-100keV)+

High resolution monochromator (∆Ε/Ε ~10-4 – 10-5….. 10-8 )

=X-ray spectroscopy

linear absorption coefficient (cm-1)

µt = ln [ I0 / I ]

t

I = I0 exp[-µt]Beer-Lambert law

Synchrotron energy tunability µ (E)

polychromatic X-rays

monochromaticX-rays

synchrotron source monochromator incident flux

monitor

sample

I0

Transmission EXAFS General method for concentrated samples

Fluorescence EXAFSHigh sensitivity to dilute species

Reflection EXAFSSurface sensitivity enhanced

Surface EXAFSDetection of Auger electrons or total electron yieldOptimal surface sensitivity BUT vacuum required

I0 I1 = I0 e -µt

I0IF ~ I0µεF

I0IR ~ I0µ f(θ)

I0Ie- ~ I0µεY

XANES EXAFS

E (eV)

abso

rptio

n co

effic

ient

µ

EELS = ELECTRON ENERGY LOSS SPECTROSCOPY

provides very similar information to XANES

• EXAFS = EXTENDED X-RAY ABSORPTION FINE STRUCTURE

• XANES = X-RAY ABSORPTION NEAR-EDGE STRUCTURE

• NEXAFS = NEAR-EDGE X-RAY ABSORPTION FINE STRUCTURE

• XAS = X-RAY ABSORPTION SPECTROSCOPY

The photoelectron behaves also as a wave

A

BAmount of water in A depends on:

presence of B (of incoming wave)

size of B (little/much if B is small/big)

whether incoming and outgoing wave crests coincide

probability of electron presence (i.e. of photon absorption) depends on:

presence of neighbour atoms

type of neighbour atoms (C or Pb)

whether RAB is a multiple of wavelength

By measuring the amount of water in A, we learn:

1. How far are the closest islands2. How many and how big they are

By measuring the probability of X-ray absorption, we learn:

1. Nearest neighbour distances2. Number and type of neighbours

A

B

λ = R/3

The probability of absorption oscillates due to constructive and destructive interference

λ = R/3.5

λ = R/4

photoelectron energy increases

wavelength λ decreases

• We’re interested in the energy dependent oscillations in μ (E), as these will tell us something about the neighboring atoms, so we define the EXAFS as:

We subtract off the smooth “ bare atom” background μ0(E), and divide by the“edge step” Δ μ0(E0), to give the oscillations normalized to 1 absorption event.

( ) ( ) ( )( )00

0

EEEE

µµµ

χ∆

−=

0.80

1.00

1.20

1.40

1.60

1.80

2.00

2.20

2.40

12000 12400 12800 13200

Abs

orpt

ion

E (eV)

µ (E

)

∆µ0

E (eV)

µ0(E)

R1

R2, R3

R(Å)

Am

plitu

de o

f FT

-0.10

-0.05

0.00

0.05

0.10

0 5 10 15 20k (A-1)

χ (k

)χ(

k)

k(A-1)

• The frequencies contained in theEXAFS signal depend on thedistance between the absorbingatom and the neighboring atoms(i.e. the length of the scatteringpath).

• A Fourier Transform of theEXAFS signal provides aphotoelectron scattering profileas a function of the radialdistance from the absorber.

NOxCO

HC

CO2

H2O

N2

Oxidation

Reduction

CeO2 ZrO2Type A Type B Type C

performanceLow High

One of the major limitations of todays car catalytic converter is the sintering of these nanoparticlesdue to operation at very high T. When this happens, the catalytic efficiency/atom is drastically reduced because of the reduction of the S/V ratio.

X-Rays

Diamond Anvil Cell (DAC)

X-Rays

Today

• 200GPa ( 2Mbar)

• T=3600K

Diamond Anvil Cell (DAC)

Quantitative Fe redox for modelling processes at the interior of planets

O. Narygina et al., PEPI (2011)

Absorption

Refractive effects

Interference effects

Collimated beam

Far or/and small source

Quasi monochromatic beam

Absorption contrast

~ 1 / E3

Phase contrast

~ 1 / E

Refractive index n for X-ray wavelengths: n ~ 0.999999

n = 1 - δ + i β

phaseamplitude

Pha

se v

s am

plitu

de

0.1

1

10

100

1000

0.1 1 10 100

Hard X-rays

Soft X-rays

Energy (keV)

(δ/β) = f(E) for Al

0.1

1

10

100

1000

0.1 1 10 100

Energy (keV)

Hard X-rays

Soft X-rays

Pha

se v

s am

plitu

de

(δ/β) = f(E) for Al

no contrast

contrast

• Contrast enhancement at interfaces Sharper images

• Less absorption Less radiation damage

• Small X-ray source

• Low divergence

• Long distance sample-source

• Monochromatic beam

d2ϕ

d2x= 0

λ= 0.7 Å

E=18keV

deformed image of whole objectaccess to phase

if recorded at different distances

D = 310 cm

Incident plane wave

d

Absorption Nearfield

D < d2/ λ

Fresnelregion

D ~ d2/ λ

Fraunhoferregion

D >> d2/ λ

Holo-tomography

each edge imaged independentlyno access to phase

only interface

D = 15 cm

50 µm

Edge enhancement

D

1 - phase retrieval with 4 distances

D = 0.21 m D = 0.51 m D = 0.90 mD = 0.03 m50 µm

D

2 – Tomographic reconstruction: 700 projections at each distance D

• Polystyrene foam• E=18keV

P.Cloetens et al., Appl. Phys. Lett. 75 (1999)

Reconstructedphase map

Tomographicslice

3D holo-tomographic reconstruction

40 µm

Quantitative density map

Improved resolution (<1µm)

P.Cloetens et al., Appl. Phys. Lett. 75 (1999)

Tem

pera

ture

composition

solid

L+S

Partial re-melting

liquid

Solidification

Absorption

β-map

50 µm

edge enhancement

Direct Imaging Phase

δ-map

Al

Al/Si

L. Salvo et al., NIM B 200 (2003)

Volume Rendering (solid transparent)

trapped liquid

Phase map

∆δ ≈ 3.5 10-8

⇓

∆ρ ≈ 0.05 g/cm3

50 µm

L. Salvo et al., NIM B 200 (2003)

Single-hole nozzle Dual-hole nozzle

high-speed fuel injection into a combustion chamber

Breakup and atomization mechanismof the fuel jet

nozzleinternal design, initial flow conditions

More efficient and cleaner combustion

Y. Wang et al., Nature Physics 4, (2008)

Single-hole nozzle Dual-hole nozzle

high-speed fuel injection into a combustion chamber

Y. Wang et al., Nature Physics 4, (2008)

Single-hole nozzle Dual-hole nozzle

high-speed fuel injection into a combustion chamber

Y. Wang et al., Nature Physics 4, (2008)

Y. Wang et al., Nature Physics 4, (2008)

32-ID at APS - ANL

• 472 ns exposure time

• 3.68 μs shot-to-shot delay

• 13.3 keV, 1014 ph s−1 mm−2/0.1% bw

Y. Wang et al., Nature Physics 4, (2008)

10µm10µm

After 40 hours at 675oCBefore heat treatment

• Developed for future generation high field magnets for particle accelerators (LHC-2, ILC).• The aim is to obtain superconducting cables with the highest critical current.• The superconducting properties are strongly dependent upon the microstructure and

microchemistry of the Nb3Sn superconducting phase.• Void formation in Nb3Sn strands causes localized stress concentrations and degrades the

physical superconductor properties.• High energy fast nano-tomography allows to study the void growth in-situ during the reaction

heat treatment.

Vertical slice from 3-D tomographic reconstruction of powder-in-tube type Nb3Sn superconductor fabricated by Shape Metal Innovation (Bruker EAS). Data acquisition time 500s

E = 46 keVM. Di Michiel, M. Scheel, A. Snigirev, I. Snigireva

Courtesy P. Tafforeau et al. ESRF-ID19

Cretaceous enigmatic tiny eggs from Thailand

absorption

Phase

P. Tafforeau et al. ESRF-ID19

THANK YOUFOR YOUR ATTENTION