Forschung am XRay FEL

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Forschung am X-Ray FEL
Gerhard Grübel Hasylab/DESY, Notke-Strasse 85,
22607 Hamburg
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Inhalt

• Einleitung
• Das Licht des XFEL
• II. Dynamik von/in Bio-Molekülen
• Pump-Probe Experimente
• Anwendungen
• III. Streuung mit kohärentem Röntgenlicht
• Speckle und Dynamik
• Strukturbestimmung am Einzelmolekül
• Magnetisierungsdynamik
• IV. Ausblick

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Properties of FEL radiation

• X-ray FEL radiation (0.2 - 14.4 keV)
• ultrashort pulse duration 100 fs
• extreme pulse intensities 1012-1014 ph
• coherent radiation x109
• average brilliance x104
• Spontaneous radiation (20-200 keV)
• ultrashort pulse duration lt200 fs
• high brilliance

x109
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Scientific applications using xray FELs

• Atoms, ions, molecules, and clusters

• Multiple ionization and multiphoton events
• Creation and spectroscopy of excited states
• (hollow atoms, Rydberg states, Laser states,
  ....)
• Dynamics, electronic geom. cluster properties

Plasma physics

• Generation of solid-density plasmas
• Plasma diagnostics

Condensed-matter physics

• Ultrafast dynamics
• Electronic structure
• Disordered materials soft matter

Materials sciences

• Dynamics of hard materials
• Structure and dynamics of nanomaterials

Chemistry

• Reaction dynamics in solid, liquid systems
• Analytical solid-state chemistry
• Heterogenous catalysis

Structural biology

• Single molecule/particle imaging
• Dynamics of biomolecules

Optics and nonlinear phenomena

• Nonlinear effects in atoms and solids
• High field science

Ultrashort pulses
Pulse intensities
Center of XFEL science
Coherence
Average brilliance
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Inhalt

• Einleitung
• Das Licht des XFEL
• II. Dynamik von/in Bio-Molekülen
• Pump-Probe Experimente
• Anwendungen
• III. Streuung mit kohärentem Röntgenlicht
• Speckle und Dynamik
• Strukturbestimmung am Einzelmolekül
• Magnetisierungsdynamik
• IV. Ausblick

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Dynamics of Biomolecules

• Example Myoglobin
• protein found in muscle, stores oxygen for
  conversion into energy.
• Structure solved in 1960 (Kendrew).
• Puzzle How does the oxygen get into and out
  of the myoglobin molecule.
• The protein is not static but dynamic with
  channels opening and closing?
• ? Time resolved Laue Diffraction
• Use CO instead of O2. Use 10 ns optical pulse
  to photodissociate CO from the Fe docking
  site. Probe dynamics with a 100 ps x-ray pulse.

Courtesy M. Wulff
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Dynamics of Biomolecules
Courtesy M. Wulff
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Dynamics of Biomolecules
Courtesy M. Wulff
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Dynamics of Biomolecules
Courtesy M. Wulff
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Dynamics of Biomolecules

• Today study (structure) and dynamics on a
• ns to ps timescale
• Tomorrow study (structure) and dynamics on a
• sub-ps timescale

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Inhalt

• Einleitung
• Das Licht des XFEL
• II. Dynamik von/in Bio-Molekülen
• Pump-Probe Experimente
• Anwendungen
• III. Streuung mit kohärentem Röntgenlicht
• Speckle und Dynamik
• Strukturbestimmung am Einzelmolekül
• Magnetisierungsdynamik
• IV. Ausblick

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Scattering with Coherent X-Rays
If coherent light is scattered from a disordered
system it gives rise to a random (grainy)
diffraction pattern, known as speckle. A
speckle pattern is an inter- ference pattern and
related to the exact spatial arrangement of the
scatterers in the disordered system. I(Q,t) ?
Sc(Q,t) ? ? fj (Q) e iQRj(t) 2
j in coherence volume c?t2?l Incoherent Light
S(Q,t) lt Sc(Q,t)gtVgtgtc ensemble
average
Aerogel ?1Å CCD (22 ??m)
Abernathy, Grübel, et al. J. Synchroton Rad. 5,
37, 1998
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Speckle Reconstruction
Reconstruction (phasing) of a speckle pattern
oversampling technique
gold dots on SiN membrane ?17Å coherent
beam at X1A reconstruction (0.1 ?m
diameter, 80 nm thick) (NSLS), 1.3.109 ph/s 10?m
pinhole oversampling technique
24 ?m x 24 ?m pixel CCD Miao,
Charalambous, Kirz, Sayre, Nature, 400, July
1999 other examples nanocrystalline materials
(Williams et al., PRL90,175501,2003 He et
al.,PRB67,174114,2003)
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Perspectives with a coherent XFEL Source

• Synchrotron Sources XFEL
• Fc/bunch ?100 ?1012
• bunches(time) 108-1010 (1-100s) 1 (100 fs)
  to record a
  speckle
  pattern (1010-1012ph)
• Structure determination of single macromolecules?
• About 20-40 of all protein molecules, including
  the important membrane proteins are difficult or
  impossible to crystallize.
• Need about 1018 ph for reconstruction of 3D
  pattern from single molecule. A single molecule
  is predicted to withstand about 1012 ph/10 fs.
• Need ? 106 single molecules
• Fast Dynamics in the Time Domain ?

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Single Molecule Diffraction
An approach to three-dimensional structures of
biomolecules by using single-molecule diffraction
images A simulation
Reconstructed 3-D pattern (from 250 2-D
projections). Phasing by oversampling
technique.
3-D structure (2.5 Å resolution) of rubisco
molecule. (106 kDa)
Top view of a section (kz0) of 3-D scattering
pattern from 106 single molecules (of known
relative orientation) each exposed by a single
10 fs XFEL pulse (?1.5Å, 0.1?m beamsize)
containing 2.1012 photons.
J. Miao, K.O. Hodgson and D. Sayre, PNAS, 98,
6641 (2001)
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Beam Sample Interaction
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Scattering with Coherent X-Rays
If coherent light is scattered from a disordered
system it gives rise to a random (grainy)
diffraction pattern, known as speckle. A
speckle pattern is an inter- ference pattern and
related to the exact spatial arrangement of the
scatterers in the disordered system. I(Q,t) ?
Sc(Q,t) ? ? fj (Q) e iQRj(t) 2
j in coherence volume c?t2?l Incoherent Light
S(Q,t) lt Sc(Q,t)gtVgtgtc ensemble
average
Aerogel ?1Å CCD (22 ??m)
Abernathy, Grübel, et al. J. Synchroton Rad. 5,
37, 1998
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Photon correlation spectroscopy (PCS)

• Gaussian fluctuations (g21g12), no optical
  mixing/heterodyning
• g(Q,t)ltI(Q,0)?I(Q,t)gt/ltI(Q)gt2 1 ?(Q)
  f(Q,t)2
• ?(Q) contrast
• f(Q,t) F(Q,t) / F(Q,0) normalized
  intermediate scattering function
• F(Q,t)(1/(Nf2(Q)) ?n?mlt fn(Q) fm(Q) exp (iQ
  rn(0)- rm(t)gt
• F(Q,0) S(Q) static structure factor
• Diffusive Processes f(Q,t) exp (-? t)
• ?min 1 / ? ? 100 ns (overlap to
  Neutron Spin Echo NSE technique)

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X-Ray Photon correlation spectroscopy (XPCS)

• Brownian motion (Silica, 2610 Å in glycerol)

time btw. frames today ? 1 s time btw. frames
XFEL ? 100 ns given by time btw. (10000)
bunches in a 1 ms long macro-bunch NOTE
the accessible time window in this example is
limited by time structure of the machine gt
delay lines cw operation
100 ns
1 ms
100 ms
V. Trappe and A. Robert
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Scattering with Coherent X-Rays
If coherent light is scattered from a disordered
system it gives rise to a random (grainy)
diffraction pattern, known as speckle. A
speckle pattern is an inter- ference pattern and
related to the exact spatial arrangement of the
scatterers in the disordered system. I(Q,t) ?
Sc(Q,t) ? ? fj (Q) e iQRj(t) 2
j in coherence volume c?t2?l Incoherent Light
S(Q,t) lt Sc(Q,t)gtVgtgtc ensemble
average fj (Q) fj (Q) fjm (Q) fj
(Q) charge-density fjm(Q) magnetization
density
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Magnetization Dynamics
?300 fs (Ni)
?1 ps (Ni)
electrons
phonons
after H. Dürr
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Magnetic X-Ray Speckle
Meandering stripe-domains in a 350 Å thick film
of GdFe2
Magnetic speckle pattern taken with a 15 µm beam
of circularly polarized X-rays tuned to the Gd M5
resonance at 1183.6 eV. Reconstruct ? structure
M-XPCS ? dynamics
J.F. Peters, M.A.deFries, J. Miguel, O.
Toulemonde, J. Goedkoop, ESRF Newsletter
34(2000)15
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