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

Outline Characteristics of synchrotron radiation (SR) SR Facilities Experimental techniques and fields of application 3 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo 3

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 electrons @ 5 GeV 4 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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. 5 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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 6 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

average Brilliance peak Properties of SR light Year 1900 1920 1940 1960 1980 2000 2020 2040 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

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 8 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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 9 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

Permanent magnet undulators Standard undulators In-vacuum Cryogenic Arrays of rare earth magnets (NdFeB, SmCo) 10 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

3rd generation SR sources Low emittance storage rings operating electrons or positrons at few GeV. 11 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

synchrotron radiation beamlineS Storage ring Optics cabin Experiments cabin Control room Simultaneous operation of beamlines 12 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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): 10-4 (few eV @ 20keV) Photon flux (dE/E = 10-4): 1013 - 1014 ph/sec Focused beam size: few mm (routinely achieved) sub-mm is more and more frequent 13 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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 14 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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 15 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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 16 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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 17 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo 17 17

A broad range of applications Beamtime used at the ESRF (2010 data) 18 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

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) 19 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo

THANK YOU! 20 EIROforum School on Instrumentation – Garching – June 2015 P. Fajardo