Developments at LCLS

Joachim Stöhr

...

but long before LCLS there was SSRL and Herman left his mark…..

Unconventional Herman

with dreadlocks

April 1, 1976 3

Herman lights up on experimental floor tries to do an experiment

Herman - a man of fashion

in sportsgear with infamous cap

5

Herman as cheerleader

leading “happy hour” with staff

6

Proud Herman first beam out of SSRL wiggler on BL4

02/28/79

Herman pushes a SASE X-FEL at SLAC

1992

February, 1992 Proposal for a hv > 300 eV FEL Based on the SLAC Linac by C. Pellegrini, UCLA February, 1992 – LCLS Technical Design Group formed by H. Winick August, 1996 – The LCLS Design Study Group, under the leadership of Max Cornacchia, begins work on the first LCLS Design Report

1998

December 1998 – The first edition of the LCLS Design Study Report is published

XFELs - a third powerful type of lightsource

J. Ullrich, A. Rudenko, R. Moshammer Ann. Rev. Phys. Chem.

63

, 635 (2012)

X-Ray Lasers are the latest light revolution

LCLS:

the world’s first x-ray free electron laser

Injector electron beam 1km linac 14GeV x-ray beam Undulator hall Near-hall: 3 stations Far-hall: 3 stations AMO SXR XPP XCS CXI MEC

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

G E ~ 0.5 eV

SASE

LCLS is rapidly gaining steam

On site users Publications by year 703 proposals

(~15 scientists/proposal)  31 countries  only 1 in 5 proposals gets beam time ~ 60% of papers in high impact journals

Beam delivery is ~95% of scheduled beam time < July

- The size and speed of things: from “structure” to “function” --

The speed of things – the smaller the faster

macro molecules molecular groups atoms “electrons” & “spins”

the technology gap

optical laser pulse

Light pulses can be used to capture (or beat) all motion…

•

Atoms: Speed of sound: 1 nm / 1 ps

•

Electrons: Fermi velocity: 1 nm / 1 fs

•

Light: Speed of light: 1 nm / 3 as

Three Strategic Science Areas of LCLS

Biological structure and function drug design, health Chemical structure and function energy, environment Material structure and function information technology Mn 4 CaO 5 cluster

Atoms Atoms/Electrons Atoms/Electrons/Spins

Biological Structure:

X-Rays are the key tool (courtesy H. Chapman) Cumulative number of structures in the PDB

ribosome myosin virus nucleosome antibody transfer RNA hemoglobin actin myoglobin

2011

Year C. Zardecki - PDB C. Abad-Zapatero - Acta Cryst D68 (2012)

Femtosecond Protein Nanocrystallography

beating the speed of sound with the speed of light atomic structure shape of nanocrystal

Liquid jet

Nanocrystals (~500nm) contained in water jet - developed at ASU Patterns of single nanocrystals recorded in single, intense and fast <50 fs x-ray shots Atoms move after shot (“speed of sound”) crystal blows up - new crystal for new shot Complete structure from ~1 million shots

First X-FEL solved protein structure Cathepsin B enzyme protein - part of the African sleeping sickness parasite

Cathepsin B glyco-protein: Famously difficult to crystallize and solve by conventional methods # shots: 4 million # of hits 10% 2Å resolution

The structure of Cathepsin B – 2 Å resolution

sugar moiety in pro-peptide Pro-peptide sugar moiety in

in-vivo

TbCatB Water R factor = 18.7% R free = 21.0%

in-vivo

TbCatB

S. Boutet (SLAC) Karol Nass (CFEL) Lars Redecke (U. Hamburg) Nano crystallography appears to be the first “killer app” of LCLS

Chemical structure: Understanding Photosynthesis

( )

Not Understood Understood

 Has created our

atmosphere

and ozone layer    Only fundamental source of

food

on earth Has created

fossil energy

sources (crude oil, coal, gas)

Photosystem II: Where Plants Split Water

Photosystem II [ ] 1 ms

Mn 4 CaO 5

X-ray damage has prevented conclusive structure determination Beat damage with intense, fast pulses

First results: room temperature study of S 1 state X-ray diffraction: atomic structure X-ray emission: electronic structure single shot diffraction pattern – 5 Å single shot pattern

• 

50 fs pulses, 3.4 × 10 11 photons∕pulse at 9 keV undamaged room temperature atomic/electronic structure



future studies will reveal reaction dynamics

Technology: Switching of information “bits”

Today’s roadmap for data storage:

Magnetic “1” and “0” bits are switched by weak field pulse aided by heat from laser

Magnetic “bits” have nanoscale dimensions

The dream: magnetic switching by a laser pulse All-optical magnetic writing

Stanciu PRL

99,

et al.,

047601 (2007) Ostler

et. al.,

Nature Comm . 3, 1 (2012)

Switching works:

  ultrafast -

40 fs optical light pulses

but only for one material – ferrimagnetic metallic GdFeCo alloy

What is the secret that makes GdFeCo work?

Use x-ray pulses to probe optical switching X-ray probe pulse 50 fs

l

~ 1.5 nm Optical pump pulse 40 fs

l

~ 800 nm CCD detector fast readout

Obtain information what happens after optical pulse  as function of D t (time)  as function of q (size)

GdFeCo not “amorphous” but inhomogeneous on nanoscale

TEM image consistent with X-ray scattering C. Graves

et al

(submitted)

nanoregions switch first – drive macroscopic switching

LCLS is being extended by LCLS-II project

Expand capacity and capability

  New injector plus 1 km linac Two new undulator sources  (TW power option) Extended spectral range from  250eV to 13 keV Experimental hall for > 4 instruments

First light in fall of 2018 Assures international competitiveness (Japan, Germany, Korea, Switzerland)

The end

The Future

•

Atomic structure

     Pursue first killer application: nanocrystal diffraction “Structure” of whole proteins (biology) and reaction centers (chemistry) Extend to “function” through pump-probe studies of dynamics Explore crystal size limits toward “single molecule imaging” Explore transient atomic structure of matter (e.g. liquids) Develop terawatt, femtoseconds pulses •

Electronic and spin structure

   Understand electronic/spin structure of excited states Key systems are chemical reaction centers and complex materials Understand x-ray/electronic interactions with controlled pulses (damage limits, non-linear processes) Develop soft x-ray seeding and pulse manipulation toolbox (split, delay, pol. control, etc)

The central problem in structural molecular biology High radiation dose causes changes in molecular structure

typical mitigation strategies:



Use large crystals: keeps dose small, periodicity enhances diffraction



Cryogenically cool crystals

Tolerable dose in cryogenically-cooled crystals ≈ 0.02 eV / atom ≈ 6 ⨉ 10 10 ph/μm 2

Data for crystals < 1 μm 2 limited by poor (s/n) data or x-ray beam damage

Elspeth Garman, U. Oxford micrograph of crystal after exposing to x-rays and warming up

Nano-crystal diffraction provides access to new class of proteins e.g. cell membrane proteins that are hard to crystallize

Materials Science: The new paradigm Structure and Properties Long range order Static disorder Equilibrium States

1900

• most reliably calculated

Function and Control Nanoscale order Dynamic order Transient excited states

2000 future

• difficult to measure and calculate

Deep Science

Mining for Matter 33