1. Photon Science at SLAC National Accelerator Laboratory Joachim Stöhr LCLS Director

2. SLAC was founded in 1962: Over the first 40 years SLAC scientists helped to establish the “Standard Model of Particle Physics”

3. 280 Overpass SLAC Professor Richard Taylor Nobel Prize 1990 LINAC completed in 1966

4. Stanford Board of Trustees Page 4 SLAC Professors Burton Richter (Nobel 1976) and Martin Perl (Nobel 1995) SPEAR completed in 1972 x-ray experiments began in 1974

5. 1999: Particle Physics Gets a Surprise! Studied with particle accelerators 1960-2000 LHC? Nobel Prize in Physics 2011 SLAC particle physics research shifted to address this challenge CAS Dry Run: October 19, 2011 (J. Stöhr)5

6. Over last six years, SLAC has shifted its focus away from particle physics

7. SLAC National Accelerator Laboratory: A proud history and an exciting future From particles to photons

8. Particle & Particle Astrophysics LCLS SSRL Change in Mission reflected in SLAC Organization Chart SLAC Director Accelerators Operations Photon Science “Photon Science” consists of x-ray user facilities x-ray research SIMES PULSE SUNCAT ….

9. electron beam x-ray beam SSRL storage ring SLAC operates two world class x-ray user facilities LCLS

10. SLAC played an important role in the last two revolutions in “light” 1879 - Invention of the light bulb 1895 - Discovery of X-Rays 1960 - Invention of the LASER 1974 - Synchrotron radiation x-rays: SSRL 2009 - The first x-ray laser: LCLS

11. Development of X-Ray Absorption Techniques: EXAFS, SEXAFS, NEXAFS Development of MAD (multiple wavelength anomalous dispersion) phasing Pioneering Soft X-Ray Science (200 – 3000 eV) (Grasshopper, Jumbo) Development of Synchrotron-Based Photoemission Techniques especially core level photoemission, photoelectron diffraction, and ARPES Development of grazing incidence surface and interface scattering First Application of Wigglers and Undulators Pioneered Coronary Angiography (medical imaging) Pioneered Magnetic Microscopy with X-Rays Pioneered X-Ray Studies in Molecular Environmental Science What is SSRL known for?

12. Bunch spacing 2 ns Bunch width ~ 100 ps beam line x-ray pulses ~ 100 ps width X-Ray pulse length determined by electron bunch length Can make shorter pulses (~ 1ps) at great loss of intensity X-Rays from Electron Storage Ring

13. What is a x-ray free electron laser, anyway? Introduction to LCLS

14. Optical laser X-ray free electron laser bound electrons in atoms - transitions between discrete states amplification through stimulated emission fixed photon energy around 1 eV compact size free relativistic electrons in bunch - radiation in periodic H-field amplification through  electron ordering in its own radiation (SASE)  electron ordering in imposed radiation (seeding) tunable photon energy up to 20 keV very large size Optical versus X-Ray Free Electron Laser

15. SASE versus self seeded x-ray beam Intense x-ray source with spiky spectrum Monochromator filter creates seed with controlled spectrum FEL amplifier (exponential intensity gain) seeded SASE 8.3 keV 40 pC

16. X-ray properties: storage ring versus FEL Assume same energy bandwidth (~ 1eV) XFEL photons in 10 fs = ring undulator photons in 1 s XFEL photons are coherent

17. LCLS: the world’s first x-ray free electron laser electron beam x-ray beam Injector 1km linac 14GeV AMO SXR XPP XCS CXI MEC Near-hall: 3 stations Far-hall: 3 stations Undulator hall

18. Far Experimental Hall Near Experimental Hall AMO SXR XPP XCS CXI MEC X-ray Transport Tunnel 200 m Start of operation Oct-09AMO November-11 XCS February-11CXI October-10XPP May-10SXR MEC April -12 LCLS X-ray Facilities

19. AMO: Atomic, Molecular and Optical Science Multi-Photon processes within atoms and molecules SXR: Soft X-ray Research Electronic and magnetic properties of materials and surfaces XPP: X-Ray Pump Probe Atomic and electronic dynamics after optical excitation CXI: Coherent X-Ray Imaging Single shot imaging of atomic and nanostructures (mostly biology) XCS: X-Ray Correlation Spectroscopy Atomic scale equilibrium dynamics in condensed matter systems MEC: Matter in Extreme Conditions Properties far, far from equilibrium LCLS instruments and their focus

20. Diffraction EXAFS Photoemission X-ray absorption X-ray emission X-ray magnetic dichroism spin pol. photoemission “Imaging” X-Rays can see the invisible --provide static and dynamic information--

21. Understanding the function of today’s devices with SSRL/ALS and tomorrow’s speed limits with LCLS SSRL LCLS ALS work has revealed how most advanced magnetic devices switch today 200ps400ps600ps800ps 100 nm 01 ns

22. X-FEL Science or The Need for Speed !

23. The speed of things – the smaller the faster atoms “electrons” & “spins” macro molecules molecular groups optical laser pulse The technology gap

24. but the devil is in the details… mechanical “speed” of motion related to concept of inertia or mass (more massive being “bigger”) F = m a …. p = m v “speed” also dependent on the process conservation laws govern dissipation of energy, linear and angular momentum e.g. friction, induction, torque detailed correlation depends on system and process of interest rule of thumb…“the smaller the faster”…. What determines the speed of things? Understanding of motion and speed essential for “function”

25. Atoms : speed of sound: 1 nm / 1 ps Electrons: Fermi velocity: 1 nm / 1 fs Light: speed of light: 1 nm / 3 as Characteristic speeds of atoms, electrons and spins

26. The new science paradigm: Static nanoscale “structure” plus its dynamic “function” The world of x-rays nanoscale dynamics smaller & faster Fundamental Timescales Operational Timescales

27. Important areas in ultrafast science Because of their size, atoms and “bonds” can change fast but how do systems evolve? key areas of interest: equilibrium (“structure”, phase diagram of a system T, P …) close to equilibrium (operation or function of a system, e.g. current flow) far from equilibrium (transient states after excitation, e.g. chemical reaction) far-far from equilibrium (transient states after extreme stimulus, e.g. a plasma)

28. Long range order Static disorder Equilibrium States Nanoscale order Dynamic order Transient States 1900 2000 future Structure and Properties Function and Control The new paradigm in understanding atomic matter The new paradigm in understanding atomic matter most reliably calculated difficult to measure and calculate

29. “Equilibrium”: What is the structure of water? Small angle x-ray scattering shows inhomogeneity Disordered soup Ice like clusters Components probably dynamic – form and dissolve - can we take an ultrafast snapshot??

30. Diffraction dataElectron density Molecular model of protein suggests its function Protein crystal In 1980s synchrotron x-rays revolutionized macromolecular crystallography Protein structure has allowed the developments of drugs However, synchrotron studies limited to large (> 5 microns) crystals Data for smaller crystals limited by x-ray beam damage A new Paradigm in Macromolecular Crystallography “beating the speed of sound with the speed of light” Studies of nanocrystals at X-FELs leads to a new paradigm conventional method

31. magnetic switching today 100nm size in 100ps - the speed of sound how fast can it be done? Electronic circuit Memory cell Magnetic structure of “bit” Computer chip “Close to equilibrium” – how does a device function: e.g. how does a spin current turn the magnetization ? “bit” in cell

32. What are the key intermediate reactive species? end reaction productsreaction dynamics & intermediates “Far from equilibrium”: How does a chemical reaction proceed?

33. “Far, far from equilibrium”: Warm and hot dense matter Al  -T phase diagram The properties of matter in extreme states - which on earth can only be created transiently on ultrafast time scale-

34. Multi-Photon processes within atoms and molecules observed - Provides new spectroscopic signatures – first non-linear effects - LCLS can drive atom-based x-ray laser Concept of “probe-before-destroy” works for atomic structure - Opens the door for atomic imaging of crystalline and disordered systems - Small protein crystals studied to < 2 Å resolution - 3D imaging of cells/viruses with nanoscale resolution appears possible - atomic structure of liquids has begun Single shot study of electronic structure of solids & surfaces is possible -“probe before destroy” also works, but electronic structure responds faster fluence limits apply because of fast (e.g. stimulated) electronic processes - Surface science studies show proof-of-principle capture of reactive states - Laser pump/x-ray probe studies have seen time resolved melting of electronic and spin structure and chemical transformations What have we learned so far?

35. LCLS in the future soft x-ray hard x-ray LCLS today

36. The end

37. User Input at Workshop Atoms = electronic cores move slow enough (inertia) that “probe before atomic motion” concept works future vision:  Maximum intensity for signal-to-noise – seeding, Terawatt beams  Short pulse length (< 10 fs) to minimize effects of atomic motion  Pursue first killer application: Bio-structures of small crystals  Extend to single macromolecule imaging - requires TW beams < 5keV Electrons respond faster, take advantage of non-linear phenomena future vision:  Control photon energy, pulse intensity and shape – seeding  Control polarization to distinguish charge & spin  Explore x-ray/electronic interactions with controlled pulses  Develop x-ray beam manipulation toolbox for non-linear x-ray optics

38. The trick to taking ultrafast pictures -- our cameras are too slow-- Use a bright flash, faster than existing shutter speed Capture bright “scattered” light flash with camera leave shutter open, flash light is stronger than background light ultrafast flash 1/20,000 second slow shutter speed 1/200 second flash duration and intensity determine picture quality x-rays can see “the invisible” nanoscale X-ray Detector slow (microseconds) X-ray Laser fast (fs), intense, short wavelength

39. Future Plans: LCLS-II and LUSI-II hard x-ray soft x-ray LCLS II:  builds the foundational facilities for enhanced capabilities and capacity  first step to remain at the international forefront LUSI II:  adds science driven instrumentation to LCLS II baseline  may include source refinements, optics enhancements, end stations

40. 5 things LCLS may become known for Motion pictures of the formation and dissociation of chemical bonds viewed at the site of selected atoms Solving the structure and time-resolved function of non-periodic macromolecular complexes (e.g. proteins) Solving the (transient) structure of disordered systems, e.g. water Characterizing the nature of transient states of matter created by radiation, pressure, fields, etc. Revealing the origins of fundamental speed limits of technological processes

41. The key challenge: Understand/control of the transient reactive state “where the action is” Conversion of chemicals Clean fuel Carbon spectra of molecules LCLS-II science example 1: Studies of carbon related reactions become possible Slide 41