Coherent Diffraction Imaging using X-ray FELs Ivan Vartaniants HASYLAB at DESY, Hamburg, Germany Revolution in X-ray Physics is just happening Revolution in X-ray Physics is just happening April 2009 FEL x-rays at 1.5 Å on a YAG screen 50 m FEL power gain length measurement after the last inserted undulator (red points) at 1.5 Å made P. Emma, et al., http://www-ssrl.slac.stanford.edu/ lcls/commissioning/documents/th3pbi01.pdf Outline 1. Introduction 2. Coherent Scattering and Phase Retrieval 3. Coherent X-ray scattering and Imaging in Material Science • Present status • Future applications 4. Requirements for Coherent X-ray scattering beamline at XFEL 5. Summary and Outlook Ivan Vartaniants | MID Workshop Grenoble 28-29 October 2009 | Page 4 Coherent Scattering and Phase Retrieval Ivan Vartaniants | MID Workshop Grenoble 28-29 October 2009 | Page 5 Coherent imaging at FEL sources Iterative phase retrieval algorithm FFT sk(x) Ak(q) Real Space Constraints Reciprocal Space Constraints s' (x) A' (q) k FFT-1 k Real space constraints: Reciprocal space constraint: use all a priori knowledge: A()I()k q → exp q •finite support •positivity R.W.Gerchberg & W.O. Saxton, Optic (1972) 35, 237 •… J.R. Fienup, Appl Opt. (1982) 21, 2758 V. Elser, J. Opt. Soc. Am. A (2003) 20, 40 CXDI in practice is working well but CXDI is a photon hungry technique We can benefit from the use of ultrabright pulses of XFEL Ivan Vartaniants | MID Workshop Grenoble 28-29 October 2009 | Page 8 The European X-Ray Laser Project XFEL CXDI Experiments at XFEL Coherent X-ray scattering and lensless imaging in materials science 9 I. Vartaniants J. Synchrotron Rad. (2007). 14, 453–470 The European X-Ray Laser Project XFEL Coherent x-ray scattering and lensless imaging in materials science Scientific aims ● 3D nanoscale structural analysis using CXDI technique ● main techniques proposed ⇒ Bragg diffraction for crystalline samples ⇒ Forward scattering for non-crystalline objects ● applications and systems of interest ⇒ Nanomaterials – properties of single particles (100×100×100 nm3 in single-shot) – quantum dots – anisotropic strain distribution of single islands (on surface or buried) ⇒ Mesoscale systems – obtain information about local properties of bulk structures avoiding averaging – metals (e.g. dislocations, nucleations) or ceramics (e.g. grain dynamics) ⇒ Dynamic processes/fluctuations – crystal surface morphology as function of time – spontaneous nucleation of clusters – crystalline fluctuations in disordered matter ⇒ Materials properties during processing – precipitates/pores growth or shrinkage – welding – laser ablation 10 I. Vartaniants J. Synchrotron Rad. (2007). 14, 453–470 The European X-Ray Laser Project XFEL Nanomaterials 107 106 105 104 103 102 (ph/sec) 101 elast I 100 10-1 10-2 0 50 100 150 200 250 300 Crystal size (μm) Elastically scattered intensity 11 2 incoming flux I0=10 ph/s·mm , E=20 keV 11 I. Vartaniants The European X-Ray Laser Project XFEL Nanomaterials (c) 200 nm 0.08 Coherent GISAXS scattering 0.06 XFEL -1 6 0.04 , Å 10 islands illuminated z q pushing the limits to 10 nm and below 0.02 0.00 -0.04 -0.02 0.00 0.02 0.04 q , Å-1 y 12 I. Vartaniants The European X-Ray Laser Project XFEL Coherent GISAXS Measurements (a) 50 nm (b) 140 nm 0.08 0.12 0.10 0.06 0.08 -1 -1 0.04 , Å z , Å q z 0.06 q 0.04 0.02 0.02 0.00 0.00 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 -0.04 -0.02 0.00 0.02 0.04 q , Å -1 -1 y q , Å (c) y 200 nm (d) 1000nm 0.08 0.05 0.04 0.06 0.03 -1 -1 0.04 , Å z , Å z q q 0.02 0.02 0.01 0.00 0.00 -0.04 -0.02 0.00 0.02 0.04 -0.02 -0.01 0.00 0.01 0.02 q , Å-1 q , Å-1 y y 13 I. Vartaniants The European X-Ray Laser Project XFEL Results of reconstruction Extension to XFEL is straightforward Time- dependent studies (reactions, oxidation, etc.) An estimate of resolution: 10-15 nm ! Not accessible by any other X-ray methods A. Zozulya, O. Yefanov, I. Vartanyants et al.,14 I. Vartaniants Phys. Rev. B 78, 121304R (2008) The European X-Ray Laser Project XFEL Extension to XFEL Scattered intensity for a narrow size distribution: coh ⎡ 1 ⎤ (Iq )= NIav ( q ⋅ )⎢ +1 ∑expq[]i Ri (− j R⎥ ) ⎣ N i≠ j ⎦ Experimental parameters for each sample during measurements Sample Average No. of Average Incoming Total Incoming Total Incoming flux Total island illuminated distance, flux, incoming flux per incoming per averaged incoming flux size, nm islands, nm ph/s flux, averaged flux per island×Nislands, per averaged Nislands ph island, averaged ph/s island×Nislands, ph/s island, ph ph 1 50 3.5·107 200 7.5·1011 5.4·1015 2.5·102 1.8·106 8.7·109 6.3·1013 2 140 4.7·106 650 3·1012 7.8·1015 2·103 5.2·106 9.4·109 2.4·1013 3 200 2.5·106 900 3·1012 1.2·1016 4·103 1.6·107 1·1010 4·1013 4 1000 7.2·105 2400 1·1012 3.6·1014 1·105 3.6·107 7.2·1010 2.6·1013 15 I. Vartaniants Extension to 3D imaging? Ivan Vartaniants | MID Workshop Grenoble 28-29 October 2009 | Page 16 Coherent X-ray Diffraction Tomography Incident angle: αi=αc=0.22° Reconstructed shape Saxs tube: CCD at 2 meters of an island Azimuthal scan ω: 1° steps O. Yefanov et al., APL 94 123104 (2009) Imaging of Biological samples with XFEL Low scattered signal Radiation damage Ivan Vartaniants | MID Workshop Grenoble 28-29 October 2009 | Page 18 Imaging of biomolecules with femtosecond X-ray pulses An elegant idea is based on measuring a sufficiently sampled diffraction pattern from a series of injected biological samples (viruses, molecules) K. J. Gaffney and H. N. Chapman, Science (2007) Imaging of biomolecules with femtosecond X-ray pulses Incident beam 1012 ph/pulse Sample Detector Single shot will produce a low resolution noisy image The European X-Ray Laser Project XFEL FLASH Facility at DESY • Jan 2005 first lasing at 32 nm • Aug 2005 start of user experiments • Energy range ~0.3 - 1GeV → ~6.5 - 60 nm (~20-200 eV) • Peak power 1-10 GW • Pulse duration <100 fs • Bandwidth Δλ/λ ~0.5 % 21 I. Vartaniants Coherent-pulse 2D Crystallography at FEL measurements at fundamental 7.97 nm Scheme of experiment Mancuso et. al. PRL 102, 035502 (2009) Coherent-pulse 2D Crystallography at FEL 10 µm 10 µm ExperimentalSymmetrized Diffraction Pattern Sample: prepared by FIB from single train (21 pulses) Coherent-pulse 2D Crystallography at FEL By using periodic array: we increase signal to noise ratio SNN/ ~ uc Conditions of experiment • beam size on the sample position: 150×150 µm2 • flux: 4.5×1010 ph/pulse • coherent flux on the sample area (0.2 sec): 1.5×1010 ph/pulse train This is at least one order of magnitude higher than at the 3rd generation synchrotron sources How to get an ultimate resolution? Recipe: • To increase signal to noise ratio • To break the symmetry Result of reconstruction Increased signal to noise ratio due to 5 ×5 times binning Extension to XFEL is straightforward 2D crystallography at shorter wavelengths with single FEL pulses Support used in Reconstructed Image reconstruction Resolution estimate: 220 nm Imaging of biomolecules with femtosecond X-ray 7 pulses IncidentIncident beambeam 101014151213 ph/pulseph/pulse SampleSample DetectorDetector To obtain a 3D image of biological samples with sub- nanometer resolution many reproducible copies will need to be measured Imaging of biomolecules with femtosecond X-ray 7 pulses Supporting membrane Incident beam Sample Detector For non-reproducible biological samples (e.g. cells) supported on the membrane same 2D projection of electron density will be measured as for injected particles The European X-Ray Laser Project XFEL SASE: Shot to Shot Fluctuations Spectral distribution at 13,7 nm W. Ackermann et al. Operation of a free-electron laser from the extreme ultraviolet to the water window Nature Photonics 1, 336 (2007) 29 I. Vartaniants 29 The European X-Ray Laser Project XFEL Study of the Early Stages of Protein Crystallization Ferritine crystal measured at room temperature XFEL pushing time resolution limits to 100 fs Evolution of a Bragg peak over time. Each image is taken 95 s apart. 30 I. Vartaniants S. Boutet&I. Robinson , J. Synchr.Rad. (2006) The European X-Ray Laser Project XFEL Requirements for Coherent X-ray Scattering beamline at European XFEL 31 I. Vartaniants The European X-Ray Laser Project XFEL Coherent x-ray imaging – Instrument requirements Requirements Instrumentation ● solid samples ● photon diagnostics ● tunable soft x-ray FEL radiation ⇒photon flux, coherence/wavefront, ● hard x-ray FEL radiation spectral distribution ● high energy spontaneous radiation ● sample manipulation & environment ⇒UHV conditions ● large area detectors ⇒solid samples X-ray beam requirements ⇒fast exchange and sample alignment ● photon energy (~1 µm) ⇒ 0.5 – 1.0 keV (transition metal L) ⇒surface preparation techniques ⇒ (3)8-12 keV (surfaces & bulk) ● detector requirements ⇒ 60-90 keV (hard materials) ⇒x-ray area detectors covering a large ⇒ bw 10-4-10-3 (long. coherence) portion of reciprocal space ● beam size ⇒ 100-1000 nm ● time domain ⇒ 10 Hz rep. rate ⇒ Pulse trains for 200 ns timescale ⇒ 10 fs synchronisation 32 I. Vartaniants J. Synchrotron Rad. (2007). 14, 453–470 Coherence at European XFEL Is it a fully coherent source? I.