2. Introduction to Synchrotron Radiation
4th EIROforum School on Instrumentation (ESI 2015)
Pablo Fajardo
Instrumentation Services and Development Division
ESRF, Grenoble

3. Outline Characteristics of synchrotron radiation (SR) SR Facilities
Experimental techniques and fields of application
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4. Synchrotron Radiation (SR)
Synchrotron radiation is produced by relativistic charged particles accelerated by magnetic fields. It is observed at particle accelerators.
The emission is concentrated in the forward direction
Natural SR divergence: 1/g ~ 100mrad for 5 GeV
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5. First use of synchrotron radiation
1947
First observation of synchrotron radiation at General Electric (USA).
Particle
physics
Synchrotron radiation
First
particle
accelerators
Particles
with more and more
energy
bigger and bigger machines
observation
of synchrotron
radiation
Construction of the first
“dedicated”
machines
1930
1947
1980
Initially considered a nuisance by particle physicists,
today synchrotron radiation is recognised as an exceptional means of exploring matter.
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6. Brilliance
The singular characteristic of SR beams is their high brilliance.
High brilliance beams = high flux of “useful photons”
high photon fluxes at the sample and detector
in particular when combined with
high energy, spatial, angular or time resolution
The brilliance of a SR beam depends inversely on the emittance of the electron beam.
(low emittance = small cross-section and divergence of the particle beam)
Both emittance and brilliance are invariant quantities in phase space  optical techniques cannot improve them
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7. average Brilliance peak
Properties of SR light
Year
105
1010
1015
1025
1030
1035
1020
X-ray tubes
4th generation FELs
3rd generation
2nd generation
1st generation
Synchrotron sources
planned
current
parasitic
dedicated
low emittance
undulator
wiggler
photons/s/mm2/mrad2/0.1%BW
average Brilliance peak
Very high brilliance
Wide spectrum (photon energy tunability)
But also :
Polarisation (selectable)
Spatial coherence (small source size)
Pulsed emission (e- bunches)
7 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

8. Insertion devices: undulators and wigglers
Electrons (or positrons) emit SR as they wiggle across N magnetic field periods (transverse oscillations).
Does each electron interfere with its own field?
NO  WIGGLER emission ~ N
YES  UNDULATOR emission ~ N2
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9. Storage rings vs. free electron lasers
Storage rings: electrons emit independently
non-amplified emission
High duty cycle is possible
Quasi-continuous (CW) source
Low energy losses
Free-electron lasers: electrons emit coherently
SR Emission is strongly amplified (SASE)
Require very low electron emittance (LINAC) and long undulators
Very short pulses: low duty cycle but huge peak brilliance
magnet arrays
electron beam
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10. Permanent magnet undulators
Standard undulators
In-vacuum
Cryogenic
Arrays of rare earth magnets (NdFeB, SmCo)
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11. 3rd generation SR sources
Low emittance storage rings operating electrons or positrons at few GeV.
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12. synchrotron radiation beamlineS
Storage ring
Optics cabin
Experiments cabin
Control room
Simultaneous operation of beamlines
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13. Some typical numbers / orders of magnitude
White beams:
Power: few kW total power
several 100 W/mm2 power density
Beam size (at 20 m): few mm
Monochromatic X-ray beams:
Energy bandwidth (dE/E): (few 20keV)
Photon flux (dE/E = 10-4): ph/sec
Focused beam size: few mm (routinely achieved)
sub-mm is more and more frequent
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14. Using X-rays as a probe
The large majority of experiments use the beam as a probe to investigate properties of a sample under study by measuring the interaction processes
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15. A complete suite of techniques
X-ray spectroscopy
X-Ray Fluorescence
Short range structure
Electronic structure
Oxidation/speciation mapping
Composition
Quantification
Trace element mapping
Very specialised
experimental stations and
sample environments
Electron spectroscopy
Absorption &
phase contrast
X-ray imaging
Molecular groups & structure
High S/N for spectroscopy
Functional group mapping
2D/3D Morphology
High resolution
Density mapping
X-ray
diffraction & scattering
Coherent scattering
Very high spatial resolution
Combines imaging and diffraction
Long/short range structure
Electron density mapping
Crystal orientation mapping
Stress/strain/texture mapping
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16. example of specialised experimental station
X-ray beam
A highly integrated instrument
KB focusing mirror
Sample stage
6 moving vacuum chambers
72 bent analyser crystals
6 pixel detectors
~250 motors
Raman spectrometer ID20/ESRF
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17. Solid-state physics Chemistry Cultural heritage Material science
Fields of application
Cultural heritage
Solid-state
physics
Chemistry
Medicine
Life sciences
Engineering
Material science
Earth sciences
Environment
Solid-state
physics
Atomic structure
Magnetic & electronic properties
Chemistry
Structure / dynamics of materials
Structure of interfaces
Cultural heritage
Non-destructive X-ray imaging
Palaeontology
Material science
High-performance materials
Soft-condensed matter
Medicine
Pharmaceutical molecules
New therapy protocols
Environment
Bacteria behaviour
Effect of heavy metals in the Environment
Life sciences
Protein crystallography
Protein dynamics
Earth sciences
Structure of Earth’s crust
Geo-dynamics
Engineering
New manufacturing / processing technologies
Material failure
Slide ILL + ESRF
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18. A broad range of applications
Beamtime used at the ESRF (2010 data)
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19. A last Example: Extreme conditions (Earth anD planetary science)
45 mm
Diamond anvil cell (DAC)
Very small sample volume (~100mm)
Pressure control up to ~1 Mbar
Temperature up to 3000 °C (laser heating)
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20. THANK YOU!
20 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo