1. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging1 Coherent X-ray Imaging Instrument Sébastien Boutet Coherent Imaging Experiments Instrument Overview Instrument Layout System Description X-ray optics Sample environments Detector Diagnostics Technical Choices Summary Coherent Imaging Experiments Instrument Overview Instrument Layout System Description X-ray optics Sample environments Detector Diagnostics Technical Choices Summary

2. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging2 Molecular Structure Determination by Protein Crystallography Molecular structure is crucial for medical applications. Inability to produce large high quality crystals is the main bottleneck. Radiation damage is overcome by spreading it over 10 10 or more copies of the same molecule.

3. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging3 Coherent Diffractive Imaging of Biomolecules Combine 10 5 -10 7 measurements into 3D dataset Noisy diffraction pattern XFEL pulse Particle injection One pulse, one measurement Gösta Huldt, Abraham Szöke, Janos Hajdu (J.Struct Biol, 2003 02- ERD-047) Wavefront sensor or second detector

4. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging4 Particle injection LCLS beam (focused, possibly optically compressed) Optical and x-ray diagnostics Pixel detector Intelligent beam-stop (wavefront sensor) To Time Of Flight (TOF) mass spectrometer Conceptual Design of CXI Instrument Readout and reconstruction

5. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging5 CXI Science at LCLS Unique Characteristics of LCLS Short pulses (100 fs) Instantaneous snapshots with no thermal fluctuations. Limited radiation damage during the exposure. Organic samples Time-resolved imaging experiments Time evolution after laser excitation High brightness (10 12 photons all at once) Perform experiment in a single shot Flash imaging of radiation sensitive samples Large Spatial coherence (~400 µm transversely for unfocused beam in the Far Experimental Hall) Coherent Imaging of larger samples LCLS has fundamental limitations in the longitudinal coherence Object size limited to 1000 x resolution unless a monochromator is used Unique Characteristics of LCLS Short pulses (100 fs) Instantaneous snapshots with no thermal fluctuations. Limited radiation damage during the exposure. Organic samples Time-resolved imaging experiments Time evolution after laser excitation High brightness (10 12 photons all at once) Perform experiment in a single shot Flash imaging of radiation sensitive samples Large Spatial coherence (~400 µm transversely for unfocused beam in the Far Experimental Hall) Coherent Imaging of larger samples LCLS has fundamental limitations in the longitudinal coherence Object size limited to 1000 x resolution unless a monochromator is used

6. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging6 CXI Instrument Location XCS AMO (LCLS) CXI Endstation XPP Near Experimental Hall Far Experimental Hall X-ray Transport Tunnel Source to Sample distance : ~ 440 m

7. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging7 System Specifications ItemPurposeSpecification Focusing optics Produce required flux.Focal spot sizes of 10,1, 0.1 micron Slits/AperturesBeam halo cleaning 0.1  m stability 1  m repeatability X-ray pulse compressor Reduce pulse length< 20 fs pulse length AttenuatorsControl incident x-ray fluxUp to 10 7 reduction at 1.5Å Slits/AperturesBeam halo cleaning 0.1  m stability 1  m repeatability Sample chamber Vacuum sample env., reduced background Vacuum below 10 -7 torr Particle injector Deliver single particles in the gas phase Particle size range : 10 – 1000 nm Particle beam focus < 150 microns Detector Measurement of diffraction pattern 2-D, 760 x 760 pixels, 120 Hz readout 110  110 µm pixel size, with central hole Sample diagnostics Analysis of sample fragments after Coulomb explosion Ion TOF : resolution of one mass unit up to 100 AMU Wavefront Sensor Measure the wavefront on every shot Resolution: 10% of the beam waist X-ray Diagnostics Intensity monitor Beam position/profile monitor 0.1% relative intensity measurement < 5% incident x-ray attenuation Photon Shutter Guard Slits Focusing Lenses Attenuators Pulse Picker Diagnostics Sample Environment Particle Injector Ion TOF-MS KB Mirrors FEH Hutch 5 Wavefront Sensor Detector Stage Compressor Beam Dump Guard Slits KB Mirrors Aperture X-ray Transport Tunnel

8. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging8 1 micron focus KB system 0.1 micron focus KB system Sample Chamber with raster stage Detector Wavefront sensor 10 micron focus Be lens (X-ray Transport Tunnel) Particle injector Ion Time of Flight

9. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging9 X-ray Optics Slit systems Variable horizontal and vertical gap from 5 μm – 5 mm Can withstand full LCLS flux – unfocused Minimal background scatter Used as cleanup slits only Slit systems Variable horizontal and vertical gap from 5 μm – 5 mm Can withstand full LCLS flux – unfocused Minimal background scatter Used as cleanup slits only D. Le Bolloc’h et al., J. Synchrotron Rad., 9, 258-265 (2002).

10. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging10 X-ray Optics Attenuators Variable, up to 10 7 reduction at 8.3 keV Coherence preserving High damage threshold Attenuators Variable, up to 10 7 reduction at 8.3 keV Coherence preserving High damage threshold

11. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging11 X-ray Optics Pulse picker Permit LCLS operation at 120 hz Millisecond shutter. Allows any pattern of pulses to be selected. Single pulses for samples supported on substrates High damage threshold Pulse picker Permit LCLS operation at 120 hz Millisecond shutter. Allows any pattern of pulses to be selected. Single pulses for samples supported on substrates High damage threshold http://www.azsol.ch/

12. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging12 X-ray Optics Beryllium Compound Refractive Lenses Produce 10  m focus For large particles > 40% throughput Positioning resolution and repeatability to 1 µm Beryllium Compound Refractive Lenses Produce 10  m focus For large particles > 40% throughput Positioning resolution and repeatability to 1 µm B. Lengeler et al., J. Synchrotron Rad., 6, 1153-1167 (1999). -40 m 0 m

13. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging13 Kirkpatrick-Baez Mirrors KB Mirror system (1 µm and 0.1 µm KB) KB mirrors have demonstrated <50 nm focus with SR Achromatic focusing. Use B 4 C as coating Damage resistant Close to 100% reflectivity KB Mirror system (1 µm and 0.1 µm KB) KB mirrors have demonstrated <50 nm focus with SR Achromatic focusing. Use B 4 C as coating Damage resistant Close to 100% reflectivity 0 m -0.4 m -4 m H. Mimura et al, Japanese Journal of Applied Physics 44, L539-L542 (2005) -40 m

14. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging14 Sample environment Sample chamber Vacuum better than 10 -7 torr Sample raster stage Aperture raster stages Optical diagnostics Sample diagnostics (Time-of-Flight Mass Spectrometers) Sample chamber Vacuum better than 10 -7 torr Sample raster stage Aperture raster stages Optical diagnostics Sample diagnostics (Time-of-Flight Mass Spectrometers) FEL

15. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging15 Sample Environment - Fixed Targets Detector Sample Aperture Particle Injector FEL

16. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging16 Sample Environment - Injected Particles Aperture The entire assembly is translated upstream to let the particle beam pass The last aperture is close to the particle beam to minimize background The entire assembly is translated upstream to let the particle beam pass The last aperture is close to the particle beam to minimize background Particle Beam Particle Injector FEL

17. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging17 Apodized Edge Apertures If 1 part in 10 6 of the LCLS beam gets scattered off the slits onto the detector, there is on average 1 photon per pixel and the background is too high! Soft edge apertures, such as etched Silicon minimize scattering. Use extra apertures to remove the scatter from the upstream apertures. If 1 part in 10 6 of the LCLS beam gets scattered off the slits onto the detector, there is on average 1 photon per pixel and the background is too high! Soft edge apertures, such as etched Silicon minimize scattering. Use extra apertures to remove the scatter from the upstream apertures. LCLS Beam

18. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging18 Particle Injector Aerodynamic lens: stack of concentric orifices with decreasing openings. Can be used to introduce particles from atmosphere pressure into vacuum Near 100% transmission achievable Creates a tightly focused particle beam. Final focus can be as small as ~10  m diameter Particle size range : 10 – 1500 nm

19. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging19 A B C D EF G A.Aerodynamic lens B.Particle beam steering C.Charge detector D.Particle beam skimming aperture E.Particle beam alignment apertures F.Time-of-flight mass spectrometer G.Faraday cup Atmospheric pressure droplets evaporate 1-10 Torr~1 Torr~0.05 Torr <1x10 -7 Torr Particles in Aerodynamically Focused Particle Beam Aerodynamic lens FEL out of page

20. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging20 Sample Diagnostics Ion TOF 3 x10 12 photons in 100 nm spot (a) 2 fs pulse (b) 10 fs pulse (c) 50 fs pulse Provide diagnostics to understand the ‘explosion’ Ion ToF detectors able to resolve single atom fragments (1 AMU) Ion TOF 3 x10 12 photons in 100 nm spot (a) 2 fs pulse (b) 10 fs pulse (c) 50 fs pulse Provide diagnostics to understand the ‘explosion’ Ion ToF detectors able to resolve single atom fragments (1 AMU) Particle Injector TOF-MS Aperture

21. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging21 Detector Tiled detector, permits variable ‘hole’ size <1 photon readout noise 110x110  m 2 pixels 760x760 pixels 10 3 dynamic range 120 Hz readout Sample-detector distance : 50-3000mm Tiled detector, permits variable ‘hole’ size <1 photon readout noise 110x110  m 2 pixels 760x760 pixels 10 3 dynamic range 120 Hz readout Sample-detector distance : 50-3000mm ‘Hole’ in detector to pass Incident beam

22. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging22 2D Pixel Array Detector High resistivity Silicon (500 µm) for direct x-ray conversion. Reverse biased for full depletion. Bump-bonding connection to CMOS ASIC. ASIC limit on size, 21 mm 2 High resistivity Silicon (500 µm) for direct x-ray conversion. Reverse biased for full depletion. Bump-bonding connection to CMOS ASIC. ASIC limit on size, 21 mm 2 Collaboration with the Gruner Group at Cornell University

23. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging23 Hartmann Wavefront Sensor Focal PlaneFocusing Optic 2D Detector FEL Beam Hartmann Plate VariableDescription Value fFocal length0.4 m4 m40 m DFocus to Hartmann plate distance5 m15 m w0w0 Focal spot size 0.1  m1  m10  m WBeam size at Hartmann plate5 mm1.5 mm0.15 mm * fDL W w0w0 * Requires a defocusing optic Detector

24. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging24 Diffractive Wavefront Reconstruction The oversampled diffraction pattern of the focus is measured. The focal spot is iteratively reconstructed using phase retrieval methods by propagating the wave from the optic to the focus and then to the detector plane. The constraints are applied at the optic and detector planes. The oversampled diffraction pattern of the focus is measured. The focal spot is iteratively reconstructed using phase retrieval methods by propagating the wave from the optic to the focus and then to the detector plane. The constraints are applied at the optic and detector planes. Focal Plane Focusing Optic 2D Detector FEL Beam f L W w0w0 Attenuator Detector

25. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging25 X-ray Diagnostics Pop-in diodes to check alignment of different optics Pop-in fluorescent screens for beam position monitoring Non destructive Be foil backscattering can monitor intensity during measurement. 95% transmission 0.1% accuracy Pop-in diode Thin Be backscattering beam monitor

26. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging26 Key Technical Choices Nanoparticle Injector Shotgun versus pulsed triggered approach Focusing Optics KB mirrors versus Be lenses or zone plates Pulse Picker Flipping blade versus rotating disks Wavefront Sensor Hartmann plate versus diffractive imaging Apertures versus slits Nanoparticle Injector Shotgun versus pulsed triggered approach Focusing Optics KB mirrors versus Be lenses or zone plates Pulse Picker Flipping blade versus rotating disks Wavefront Sensor Hartmann plate versus diffractive imaging Apertures versus slits

27. Sébastien Boutet sboutet@slac.stanford.edu LCLS FAC Meeting Oct 30, 2007 Coherent X-ray Imaging27 Summary Instrument designed for imaging of submicron particles at near atomic resolution. Sample environments Fixed targets Injected samples X-ray optics can tailor FEL parameters for users 3 focal spot size : 0.1, 1 and 10 microns Variable attenuation Single pulse selection with pulse picker Instrument designed for imaging of submicron particles at near atomic resolution. Sample environments Fixed targets Injected samples X-ray optics can tailor FEL parameters for users 3 focal spot size : 0.1, 1 and 10 microns Variable attenuation Single pulse selection with pulse picker