Applications of Coherent X-Rays at the LCLS

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1 Applications of Coherent X-Rays at the LCLS Gerhard Grübel Notke-Strasse Hamburg Germany SLAC, October 17,

2 LCLS and coherence based techniques Imaging techniques (CDI, FTH) X-Ray Photon Correlation Spectroscopy (XPCS) Recent developments and results Conclusions SLAC, October 17,

3 LCLS Characteristics LCLS radiation (0.8-8 kev) ultrashort pulse duration 100 fs extreme pulse intensities ph coherent radiation Coherence based Imaging techniques Coherent Diffraction Imaging (CDI) Fourier Transform Holography (FTH) X-ray Photon Correlation Spectroscopy (XPCS) SLAC, October 17,

4 Coherence Coherence based based Imaging Imaging techniques techniques Phase retrieval algorithm lensless, resolution limited hard x-rays: shorter lengthscales, bulksensitivity and compatibility with extreme conditions obey over-sampling condition or use reference beam (FTH) Short pulse: snapshots (pump-probe) overcome damage limits SLAC, October 17,

X-Ray Photon Correlation Spectroscopy (XPCS) dynamics on short lengthscales in the time domain reciprocal space technique hard x-rays: shorter lengthscales,

5 X-Ray Photon Correlation Spectroscopy (XPCS) dynamics on short lengthscales in the time domain reciprocal space technique hard x-rays: shorter lengthscales, bulk-sensitivity and compatibility with extreme conditions (coherent) flux limited (τ >μs) S(Q,t) dynamic structure factor Short pulse: ns-fs timescale SLAC, October 17,

6 LCLS and coherence based techniques Imaging techniques (CDI, FTH) X-Ray Photon Correlation Spectroscopy (XPCS) Recent developments and results Conclusions SLAC, October 17,

$Coherent Diffraction Imaging (CDI) Reconstruction (phasing) of a speckle pattern:$ (0.1 μm diameter, 80 nm thick) (NSLS), 1.3.

7 Coherent Diffraction Imaging (CDI) Reconstruction (phasing) of a speckle pattern: oversampling technique gold dots on SiN membrane λ=17å coherent beam at X1A reconstruction (0.1 μm diameter, 80 nm thick) (NSLS), ph/s 10μm pinhole oversampling technique 24 μm x 24 μm pixel CCD Miao, Charalambous, Kirz, Sayre, Nature, 400, July 1999 SLAC, October 17,

$Single Molecule Diffraction An approach to three-dimensional structures of biomolecules by using singlemolecule diffraction images: A simulation$ (106 kda) Top view of a section (kz=0) of 3-D scattering pattern from 10 6 single molecules (of known relative orientation) each exposed by a

(106 kda) Top view of a section (kz=0) of 3-D scattering pattern from 10 6 single molecules (of known relative orientation) each exposed by a

8 Single Molecule Diffraction An approach to three-dimensional structures of biomolecules by using singlemolecule diffraction images: A simulation 3-D structure (2.5 Å resolution) of rubisco molecule. (106 kda) Top view of a section (kz=0) of 3-D scattering pattern from 10 6 single molecules (of known relative orientation) each exposed by a single 10 fs XFEL pulse (λ=1.5å, 0.1μm beamsize) containing photons. Reconstructed 3-D pattern (from D projections). Phasing by oversampling technique. J. Miao, K.O. Hodgson and D. Sayre, PNAS, 98, 6641 (2001) SLAC, October 17,

9 Beam Sample Interaction SLAC, October 17,

Deformation fields inside nanocrystals I.K. Robinson, I.A. Vartaniants, G.J. Williams, M.A. Pfeifer, J.A. Pitney, Phys. Rev. Lett. 87, 195505 (2001) M.A. Pfeifer, G.

38Å coherent x-rays and CCD tuned to the Pb (111) reflection (with 2 images separated by a 0.01 deg. rotation of the sample shown below).

of the local deformation of the crystal onto the Q vector of the Bragg peak being measured. Reconstructed electron density revealing (111) facets.

10 Deformation fields inside nanocrystals I.K. Robinson, I.A. Vartaniants, G.J. Williams, M.A. Pfeifer, J.A. Pitney, Phys. Rev. Lett. 87, (2001) M.A. Pfeifer, G.J. Williams, I.K. Vartaniants, R. Harder and I.K. Robinson, Nature 442, 63 (2006) CDI of (about 750 nm) Pb nanocrystals on Si substrate illuminated with 1.38Å coherent x-rays and CCD tuned to the Pb (111) reflection (with 2 images separated by a 0.01 deg. rotation of the sample shown below). Density of crystals is regarded as a complex function with the real part being the electron density and the imaginary part representing the projection of the local deformation of the crystal onto the Q vector of the Bragg peak being measured. Reconstructed electron density revealing (111) facets. Reconstructed imaginary part revealing (in the center) a phase-shift corresponding to about 1.1/2π (111) lattice spacings or about 0.5Å SLAC, October 17,

11 Fourier Transform Holography Random magnetic (stripe) domains in a [Co(4)Pt(7)] 50 ML sample, illuminated together with a reference aperature (1.5 µm) at the Co LIII edge absorption edge with a 778 ev (1.59 nm) 20 µm coherent soft x-ray beam. S. Eisebitt, J. Lüning, W.F. Schlotter, M. Lörgen, O. Hellwig, W.Eberhardt and J. Stöhr, NATURE, 432, 885 (2004) SLAC, October 17,

Incident FEL pulse: 25 fs, 32 nm, 4x10 14 W cm -2 (10 12 ph/pulse)

12 Femtosecond Imaging Model structure in 20 nm SiN membrane Speckle pattern recorded with a single (25 fs) pulse Reconstructed image Incident FEL pulse: 25 fs, 32 nm, 4x10 14 W cm -2 (10 12 ph/pulse) H. Chapman et al., Nature Physics, 2,839 (2006) SLAC, October 17,

$High-Resolution Scanning X-ray Diffraction Miroscopy P. Thibault, M. Dierolf, A. Menzel, O. Bunk, C, David, F.$ $al.,.), Wigner Deconvolution (Rodenburg, Chapman,..) 201x201 diffraction pattern (6.$

13 High-Resolution Scanning X-ray Diffraction Miroscopy P. Thibault, M. Dierolf, A. Menzel, O. Bunk, C, David, F. Pfeiffer, Science, vol 321, 381 (2008) Measure multiple (overlapping) diffraction patterns (as suggested e.g. by Rodenburg et al. and known as ptychography) to provide overdetermination in the data followed by a reconstruction algorithm(s): Difference map (Elser), Ptychography (Rodenburg et al.,.), Wigner Deconvolution (Rodenburg, Chapman,..) 201x201 diffraction pattern (6.8 kev), 300 nm beam ( 100 nm steps with 300 nm beam), 50 ms exposure from a 30 μm diameter Fresnel zone plate with 70 nm outer zone width. SLAC, October 17,

$Hard X-Ray Holographic Diffraction Imaging L.M. Stadler, C.$ Grübel; Phys. Rev. Lett.

P ) 200 nm structure width; 220 nm height and 5 x 175 nm Au

14 Hard X-Ray Holographic Diffraction Imaging L.M. Stadler, C. Gutt, T. Autenrieth, O. Leupold, S. Rehbein,Y. Chuskin and G. Grübel; Phys. Rev. Lett. 100, (2008) Combine FTH and CDI: Au nanostructure (letter P ) 200 nm structure width; 220 nm height and 5 x 175 nm Au reference dots on 50 nm Si 3 N 4 illuminated with 8 kev (10x10 μm 2 ) beam. Use Fourier Transform Hologram as input for the CDI hybrid-input algorithm. Find resolution of about 25 nm and retrieve height of object: 235 nm +/- 10% SLAC, October 17,

$Ultrafast single-shot diffraction imaging of nanoscale dynamics Ultrafast single-shot diffraction imaging of nanoscale$ , nature photonics 2, 415 (2008) Pump-probe experiment on nano-patterned (FIPetched) Si 3 N 4 membrane (Ir-coated)

, nature photonics 2, 415 (2008) Pump-probe experiment on nano-patterned (FIPetched) Si 3 N 4 membrane (Ir-coated)

15 Ultrafast single-shot diffraction imaging of nanoscale dynamics Ultrafast single-shot diffraction imaging of nanoscale dynamics A. Barty et al., nature photonics 2, 415 (2008) Pump-probe experiment on nano-patterned (FIPetched) Si 3 N 4 membrane (Ir-coated) pumped with Nd:YLF 523 nm, 12.5 ps long 25 μj pulses and probed with 10 fs 13.5 nm 20 μm FLASH pulses. Correlation functions indicate sample disintegration with a speed of about m/s SLAC, October 17,

16 Summary: Imaging Techniques Summary enormous progress since the 1999 paper impressive progress in solving the inversion problem better understanding of the damage problem much progress towards biological systems (particle injection systems, molecular orientation,..) new methods emerge (ptychography, combination CDI+FTH, FTH+URA,..) considerable single shot experience (XUV) ultimately achievable resolution for small systems still under discussion FEL light in the hard X-ray regime is missing SLAC, October 17,

17 LCLS and coherence based techniques Imaging techniques (CDI, FTH) X-Ray Photon Correlation Spectroscopy (XPCS) Recent developments and results Conclusions SLAC, October 17,

X-Ray Photon Correlation Spectroscopy (XPCS) first (X-ray) speckle in 1991 (X25) Diffuse (001) peak of Cu 3 Au M. Sutton, S.G.J. Mochrie, T. Greytak, S.E. Nagler, L.E. Be

18 X-Ray Photon Correlation Spectroscopy (XPCS) first (X-ray) speckle in 1991 (X25) Diffuse (001) peak of Cu 3 Au M. Sutton, S.G.J. Mochrie, T. Greytak, S.E. Nagler, L.E. Berman, G.A. Held and G.B. Stephenson, Nature 352, 608 (1991) XPCS critical dynamics in Fe 3 Al (1995) 1st g 2 (t) function: colloidal gold (1995) multitude soft matter studies (colloids, polymers...) non-equilibrium dynamics (1998) surface dynamics (2001) heterogeneous dynamics,.. cdw, magnetism,... SLAC, October 17,

19 X-Ray Photon Correlation Spectroscopy (XPCS) g 2 (Q,t) = <I(Q,t) I(Q,t+τ)> <I(Q,t)> 2 g 2 (Q,t) = 1 + f(q) f(q,t) 2 f(q,t): intermediate scattering function f(q,t) = exp [(-Γ t) ß ] single Q (point detector): fast 2-D multi-q (CCD detector): slow ß > 1,=1,<1 SLAC, October 17,

20 Dynamics of complex fluids A. Robert J.Appl.Cryst.40,s34(2007) silica (R=2610Å) in glycerol; T= 259 K; η=56 Pas f(q,t) = exp (-Γt) Γ(Q) = D(Q) Q 2 D(Q) D 0 =k B T/6πηR H SLAC, October 17,

21 Dynamics of complex fluids Mochrie, Mayes, Sandy, Sutton, Brauer, Stephenson, Abernathy, Grübel, Phys. Rev. Lett. 78, 1275 (1997) PS-PI (R=23.7 nm) micelles in PS matrix at T 293 K (top) and 393 K (bottom) The most likely density fluctuations decay the slowest (degennes narrowing) SLAC, October 17,

22 Non-equilibrium Dynamics Malik, Sandy, Lurio, Stephenson, Mochrie, McNulty, Sutton, PRL 81, 5832 (1998) Phase separating Glass (Na 2 O) 0.07 (B 2 O 3 ) 0.22 (SiO 2 ) 0.71 T=1033K quench (B 2 O 3 )-rich (SiO 2 )-rich 943K<T<963K SLAC, October 17,

23 Two time correlation function <I(t 1 ) I(t 2 )> - <I(t 1 )> <I(t 1 )> C(q,t 1,t 2 ) = [<I 2 (t 1 )> - <I(t 1 )> 2 ] 1/2 [<I 2 (t 2 )> - <I(t 1 )> 2 ] 1/2 Fluctuations τ = τ ( q,t ) Δt = t 1 -t 2 t = (t 1 +t 2 )/2 Two time correlation function τ (q,t) = [t max (q)-t o ] { a [t-t o ] / [t max (q)-t o ] } (1-n) x τ(q,t) ~ 1/q t 2/3 ^ a = 0.72(2) (1-n) = 0.65(4) = 1 ⅓ SLAC, October 17,

24 Surface dynamics Seydel, Madsen, Tolan, Grübel, Press, Phys. Rev. B 63, (2001) Glassforming liquid: glycerol Γ(Q) = c Q c = γ(t)/2η(t)} SLAC, October 17,

25 Particle Dynamics in Polymer-Metal Nanocomposite Thin Films S. Narayanan, D.R. Lee, A. Hagman, X. Li and J. Wang, Phys. Rev. Lett. 98, (2007) Entangled polymer [120, 65 kg/mol]: Relaxation time ~ q R -1 (-0.9) drift mechanism ß > 1 Less entangled polymer [30 kg/mol]: aging, jamming Relaxation time ~ q -1.6 R particles move faster, governed by ß< 1 hydrodynamic interactions Au nanoparticles (0.9nm) on polystyrene (PS; R G =5-10nm) on Pd (Cr) Si substrate. R AU < R G probe individuality of polymer. Increase intensity by wave-guiding effects SLAC, October 17,

Autocorrelation function of the [200] Bragg peak and the CDW superlattice peaks [2-2δ,0,0].

26 Antiferromagnetic domain fluctuations Shpyrko, Isaacs, Logan, Feng, Aeppli, Jaramillo, Kim, Rosenbaum, Zschack, Sprung, Narayanan, Sandy, Nature, 447, 68 (2007) Chromium supports a SDW (including domain walls). The SDW is accompanied by a CDW. Autocorrelation function of the [200] Bragg peak and the CDW superlattice peaks [2-2δ,0,0]. Slow component indicative of thermally activated domain wall dynamics at high T and T independent switching (tunneling) at low T. SLAC, October 17,

27 Summary: Imaging Techniques Summary steady progress since the 1991 paper many applications from many different fields (soft matter, hard matter, surfaces and interfaces) indicating that XPCS has achieved quite some maturity accessible dynamics mostly slow (τ > μs) and at moderate Q limited by fast 2-d detectors but ultimately by coherent flux fast (ns-fs) and(or) large Q dynamics only at a FEL source need XCS beamline asap SLAC, October 17,

28 SR based XPCS data 2-D surface 1-D SLAC, October 17,

29 Summary: Imaging Techniques Questions: How to do (fast) dynamics experiments at a 120 Hz machine? Is there enough intensity to (single-shot) image e.g. a magnetic system? Can two subsequently recorded (speckle) pattern be compared? SLAC, October 17,

30 XPCS at LCLS: movie mode Movie mode allows access to slow dynamics: f << 1/ΔT = 120 Hz SLAC, October 17,

31 Delay-Line Mode Delay Line: 1ps <Δt <10ns (1ns 300 mm) Delay-Line mode allows access to fast (fs-ns) dynamics SLAC, October 17,

32 X-ray delay-line E=8.388 kev 8 x Si(511) Tuning range: 0 ΔT 2.83 ns available via DESY-SLAC MoU talk Roseker SLAC, October 17,

33 Summary: Imaging Techniques Questions: How to do (fast) dynamics experiments at a 120 Hz machine? Is there enough intensity to (single-shot) image e.g. a magnetic system? Can two subsequently recorded (speckle) pattern be compared? SLAC, October 17,

34 Prototype experiments at Flash FLASH the Free Electron Laser Facility Hamburg operating from 50 nm to 6.5 nm SLAC, October 17,

35 Photon parameters at FLASH: Magnetism? FLASH operates for λ > 6.5 nm wavelength average energy per pulse photons per pulse 778 ev Co L III edge fundamental 7.97nm ~ 12 µj 4.8 * rd harmonic 2.66nm ~ 72 nj 1.0 * th harmonic 1.59nm ~ 3.5 nj 2.8 * 10 7 pulse duration 10 fs at 8.0 nm 1 fs at 1.6 nm SLAC, October 17,

36 Sample CoPd multilayer, CoPt multilayer Hitachi (Hellwig), UHH (Oepen) 150 nm SiN membrane, 20 nm Pd base, 50 repeats of Co(1.2nm)/Pd(0.8nm), capped with 1.2 nm Pd providing out of plane magnetic moments Actors C. Gutt 1, L.M. Stadler 1, S. Streit-Nierobisch 1, C. Günther 2, R. Könnecke 2, B. Pfau 2, S. Eisebitt 2, A.P. Mancuso 1, J. Gulden 1, B. Reime 1, E. Weckert 1, J. Feldhaus 1, I.A. Vartaniants 1, F. Staier 3, A. Rosenhahn 3, R. Barth 3, M. Grunze 3,M. Martins 4, O. Hellwig 5, H. Stillrich 6, D. Stickler 6, R. Frömter 6, H.P. Oepen 6, T. Nisius 7, T. Wilhein 7, K. Honkavaara 1, B. Faatz 1, R. Treusch 1, S. Schreiber 1, E. Saldin 1, E. Schneidmiller 1, M. Yurkov 1 and G. Grübel 1 1 DESY, Hamburg, Germany 2 BESSY, Berlin, Germany 3 Physikalische Chemie, Universität Heidelberg, Germany 4 Experimentelle Physik, Universität Hamburg, Germany 5 Angewandte Physik, Universität Hamburg, Germany 6 FH Koblenz, Remagen Germany PRL (submitted) SLAC, October 17,

37 Experimental Setup Setup PG 2 Beamline monochromator 200 lines per mm dispersive element : temporal broadening of pulse ca fs (ray-tracing) but transmission only 10-4 at 800 ev Instrument: M. Martins, M. Wellhöfer, J.T. Hoeft, W. Wurth, J. Feldhaus, and R. Follath, Rev. Sci. Instrum. 77, (2006) SLAC, October 17,

38 783.5 ev (off resoanance) SLAC, October 17,

778.1 ev (resonant Co L-edge) q max =0.033 nm -1 1000 s exposure (21 pulses x 5 Hz) Frame contains 6.

39 778.1 ev (resonant Co L-edge) q max =0.033 nm s exposure (21 pulses x 5 Hz) Frame contains 6.7 x 10 4 photons Need x 10 5 for single shot (get 10 4 from beamline transmission and 10 4 from fundamental = x10 8 ) SLAC, October 17,

40 Scattering close to the Co M edge Single bunch mode; 5 bunches/s E<59.9 ev (fundamental) CoPt 23.5 nm (off resonance) 20 fs (single shot) 5 μj (5x10 11 ph/pulse) SLAC, October 17,

41 Resonant Scattering at the Co M edge Single bunch mode; 5 bunches/s E=59.9 ev (fundamental) CoPt 20.7 nm (on resonance) 20 fs (single shot) 5 μj (5x10 11 ph/pulse) SLAC, October 17,

42 Resonant Scattering at the Co M edge Single bunch mode; 5 bunches/s 1-st bunch 2-nd bunch CoPt 20.7 nm (on resonance) 20 fs (single shot) 5 μj (5x10 11 ph/pulse) SLAC, October 17,

Single bunch mode; 5 bunches/s 25 20 FEL pulse energy [µj] 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

43 Single bunch mode; 5 bunches/s FEL pulse energy [µj] CoPt 20.7 nm (on resonance) 20 fs (single shot) 5 μj (5x10 11 ph/pulse) SLAC, October 17,

44 Magnetic speckle pattern from two consecutive single shots low pulse energy XPCS is feasible!! SLAC, October 17,

45 Summary There is a route towards doing fast XPCS at a FEL machine. (delay-line mode) A prototype X-ray delay-line is tested and ready for use. Standard (movie mode) XPCS is straight forward. There is a series of very interesting experiments that are ready to go. XCS beamline in 2011/2012 comes too late. The inversion problem seems to be under control. Good understanding of the damage problem Much progress toward biological systems (particle injection systems, molecular orientation,..) Considerable single shot experience (XUV) Hard FEL X-rays are missing Detectors remain an issue. Information on the dynamics of a system can also be obtained by Imaging. The choice (XPCS vs. Imaging) depends on the problem. XPCS is less demanding since the inversion problem does not exist. SLAC, October 17,

46 Layout Thank you for your attention SLAC, October 17,

A facility for Femtosecond Soft X-Ray Imaging on the Nanoscale

A facility for Femtosecond Soft X-Ray Imaging on the Nanoscale Jan Lüning Outline Scientific motivation: Random magnetization processes Technique: Lensless imaging by Fourier Transform holography Feasibility: