X -ray C orrelation S pectroscopy Instrument

1. X-ray Correlation Spectroscopy Instrument Aymeric Robert – XCS Instrument Scientist LCLS Facilities Advisory Committee Meeting November 12, 2008 Team Leaders : Brian Stephenson Gerhard Grübel Karl Ludwig Lead Engineer: Eric Bong

2. X-ray Photon Correlation Spectroscopy Coherent Scattering (Speckles) Coherent X-rays Speckles : scattering patterns produced by the coherent illumination of the sample XPCS : observation of the time-fluctuation of speckle patterns Characterization of the underlying dynamics of the system XPCS is independent of the scattering geometry (SAXS, Diff., GI-SAXS, Refl.,…) XPCS probes dynamical phenomena

3. Photon Shutter Primary Slits Diagnostics Monochromator Secondary Slits Transport Tunnel Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker Harm. Rej. Mirrors Defining Slits FEH Hutch 4 Diagnostics Diffractometer Large Angle Detector Stage • Goal • Time-resolved observation of coherent diffraction patterns using LCLS coherent hard x-rays (6-25keV) • Tailor and characterize X-ray beam parameters • Spatial profile • Intensity • Repetition Rate • Spectral Bandwidth • X-ray Photon Correlation Spectroscopy Requirements • Versatility of the instrumentation (SAXS, WAXS, GI) • Coherence preservation of x-ray optics (to the extent possible) • Detector with small pixel size/Large sample-detector distance • Key Performance Parameters • 6-20 keV energy range • Using the fundamental and third harmonic • 0.1-0.01% energy resolution

4. Large Angle Detector Mover • & Diffractometer • Sample/detector distance 7-8m • Decoupled from diffractometer • SAXS, WAXS, GI • 2θ up to 55º, vertical tilt • Height adj. Photon Shutter Primary Slits Diagnostics Monochromator Secondary Slits Transport Tunnel Diagnostics Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker Harm. Rej. Mirrors Defining Slits FEH Hutch 4 Diagnostics Diffractometer Large Angle Detector Stage

5. Previous FAC Reports • FAC Report Oct 2007 • The committee recommends that the XCS staff retain flexibility in their designs to facilitate change as opportunities and problems are discovered. • FAC Report Jun 2008 • “ … the committee endorses the decisions that have been made to date.” • “ The large offset monochromator also requires design attention and carries risk. This has been recognized by the project and appropriate efforts are being made to create a solid design”

6. Monochromator Photon Shutter Primary Slits Diagnostics Secondary Slits Transport Tunnel Diagnostics Split and Delay Monochromatization scheme for XCS Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker Harm. Rej. Mirrors Defining Slits FEH Hutch 4 Diagnostics Diffractometer Large Angle Detector Stage

7. Motivations Photon Shutter Primary Slits • XCS Science (i.e Early Science) • XCS Science NEEDS a monochromator • Satisfaction of the XCS User Community Diagnostics Monochromator Secondary Slits Transport Tunnel Diagnostics First Coherence Workshop Application of Coherent X-rays at the LCLS 10/17/2008 Split and Delay Secondary Slits Diagnostics Focusing Lenses Photon Shutter Attenuators Pulse Picker Harm. Rej. Mirrors Defining Slits FEH Hutch 4 Diagnostics Diffractometer Large Angle Detector Stage

8. Near Experimental Hall X-ray Transport Tunnel (200m long) XCS Source to Sample distance : ~ 420 m Transport Tunnel Far Experimental Hall FEH Hutch 4 High Energy Density Coherent X-ray Imaging X-ray Correlation Spectroscopy Original Plan for XCS

9. Original Plan for XCS Monochromator Total Budgeted cost: 1.2M$ Delivery date : 2012 Associated XRT cost : ~0.8M$ Transport Tunnel • Double crystal Large Offset Monochromator • Energy Range : 6-25keV • Offset : 600mm • Design similar to XPP • Location at the entrance of the XRT (200m) • Possibility of changing the crystal • Preserve “future” capability of multiplexing (i.e. thin crystals FEH Hutch 4

10. ~35m New Plan for XCS Monochromator Total Budgeted cost: 1.2M$ Delivery date : 2012 Associated XRT cost : ~0.8M$ Transport Tunnel BUT • Double crystal Large Offset Monochromator • Energy Range : 6-25keV • Offset : 600mm • Design similar to XPP • Location at the entrance of the XRT (200m) • Possibility of changing the crystal • Preserve “future” capability of multiplexing (i.e. thin crystals FEH Hutch 4

11. Plan for XCS Monochromator Transport Tunnel FEH Hutch 4 How to satisfy the request for early science from the XCS User Community and provide early science capabilities ?

12. Plan for XCS MonochromatorS Transport Tunnel • Use part of the saving from the XRT transport cost to purchase a commercially available High Resolution Double Crystal Monochromator ( pseudo channel cut in vertical scattering geometry )* with small “almost” fixed exit allowing the use of multiple standard reflections and covering easily the LCLS hard x-ray range 6-25keV • Ease polishing of each monochromator crystal • This can be purchased early (very early) FEH Hutch 4 * For LCLS hard x-ray beam, there is no heat load issue. The major issue of that type of monochromator is known to be the cooling system which in our case is irrelevant

13. Plan for XCS Monochromator • Impact on XCS instrument design :almostNONE • Operation for some time with just the HR-DCM • Operation of XCS in CXI line (LCLS main line) • The table supports for optics/diagnostics are identical to XPP instrument and allow that operation with a 600mm offset • The diffractometer can be placed in either line (CXI/XCS) • The Large Angle detector mover can have its center of rotation on both the CXI and XCS line Transport Tunnel FEH Hutch 4 Provide earlier science capability for the XCS Instrument Which other benefits ?

14. Monochromator for LCLS Instruments : Phase I • Provide the High Resolution Double Crystal Monochromator to the XPP Instrument • Provide the first early LCLS monochromatic beam • Test the monochromator • Provide temporarily monochromatic beam to XPP • Gives XPP more time to get their own monochromator • Allow EARLY Coherent Scattering experiments in the XPP experimental hutch with control of the longitudinal coherence length (CXI/XCS) XPP X XCS CXI

15. Monochromator for LCLS Instruments : Phase II • Provide the High Resolution DCM to hard X-ray Coherence Instruments XCS or CXI • Provide the first early LCLS monochromatic beam in FEH • Test the monochromator close to FEH location (far from source and close to definite monochromator location) • Provide temporarily monochromatic beam to CXI • Allows early commissioning of XCS Instrument • Evaluation of the impact of very hard coherent x-rays on XCS Science Program • Allow EARLY Static and Dynamic Coherent Scattering Science in the CXI or XCS experimental hutches with control of the longitudinal coherence length XCS CXI

16. Monochromator for LCLS Instruments : Phase III • Return High Resolution DCM to XCS • Use of HR-DCM as Post Monochromator for experiments requiring very large longitudinal coherence lengths • Allow to relax the parameters of the LO-DCM to use a single type of crystal (Si (220) for example) as post monochromatization can be achieved with the HR-DCM • The compensation in terms of lower ΔE/E as compared to Si (111) could be obtained with proper focusing optics (i.e CRL’s) • If multiplexing : a single and identical crystal in CXI beam (i.e easy to correct if necessary) XCS CXI

17. Monochromator for LCLS Instruments • XCS Team Leader Meeting Oct 19, 2008 • Move the large-offset and split/delay from about 200m upstream of experiment to about 40m upstream of experiment • We therefore endorse moving the large-offset monochromator to the new location. • Adding post-monochromator to scope • Such a double-crystal monochromator is commercially available, and could be procured immediately for initial use in providing monochromatic beam to all of the early hard x-ray experiments. This will be extremely important for the scientific program. In particular, this will allow the early commissioning of the XCS experiments with the required monochromatic beam prior to the availability of the large-offset monochromator. All of the other XCS beamline components are compatible with operation in the in-line configuration without the large-offset monochromator. • We therefore endorse the concept of adding to the scope a double-crystal, small-vertical-offset monochromator with either multiple or easily changeable crystals. • The CXI team was involved in the discussion and supports the proposed plan

18. Summary The cost of the post monochromator (2) should be significantly less than the cost savings associated with moving the location of the large offset monochromator downstream (1). Thus the net result of these changes will be to improve performance, improve capability, and making monochromatic x-ray beam available earlier to all experiments, while decreasing cost.* * XCS Team Leader Meeting Summary Oct 2008 • Early Science for XCS, CXI, XPP • No increase of cost ( i.e even slight cost saving) • XCS instrument commissioned early (with HR-DCM) • Satisfies the expectation of the XCS User Community • Serve the Science Mission of the 3 LCLS hard x-ray instruments

19. Additional Slides XCS Science

20. D t Intensity autocorrelation function D t D t D t D t 4 D t 3 2 1 1 2 • Time-average Brilliance • 10 ms < tC < hrs • Large Q’s accessible 3 4 Sequential XCS

21. Peak Brilliance & Pulse Duration • pulse duration < tC< several ns • Large Q’s accessible Ultrafast XCS : Split & Delay Detector

22. Ultra Fast Mode High Time–average Brilliance Rep. Rate 120 Hz Sequential Mode High Peak Brilliance Short pulse duration 230fs XCS Science @ LCLS LCLS Parameters Full Transverse Coherence 8 and 24 keV Dedicated 2D-Detector

23. Multi-crystal XCS Monochromator