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XPCS at the APS: Implementation and Operations

XPCS at the APS: Implementation and Operations . Alec Sandy X-Ray Science Division Argonne National Laboratory. Acknowledgements. Sector Staff Suresh Narayanan Michael Sprung TRR Group Leader Jin Wang Former CAT members and continuing active partners: Larry Lurio Simon Mochrie

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XPCS at the APS: Implementation and Operations

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  1. XPCS at the APS: Implementation and Operations Alec Sandy X-Ray Science Division Argonne National Laboratory

  2. Acknowledgements • Sector Staff • Suresh Narayanan • Michael Sprung • TRR Group Leader • Jin Wang • Former CAT members and continuing active partners: • Larry Lurio • Simon Mochrie • Mark Sutton

  3. Outline • Background • Mission • Implementation • Scientific and General User Program • Opportunities for Improvement (at NSLS-II) • Challenges

  4. Background • Sector 8-ID • ≤ 2002 IMM-CAT • IBM, McGill and MIT • Multiple experiment capabilities promised in PDR but not delivered because of costs and dwindling PI participation • Beamline specialization a hidden benefit • One of first 3 CAT’s designated by DOE for transition to APS operational responsibility • 2003–current • Transition to APS XOR operations completed • IMMY/XOR CAT → XOR 8-ID • Beamline staffed with APS personnel within the Time Resolved Research Group • Beamtime allocated via APS General/Partner User system • Capital and operational funds via APS

  5. Mission • Beamline Mission • Develop and apply X-Ray Photon Correlation Spectroscopy (XPCS) to the study of equilibrium and non-equilibrium dynamics in condensed matter • Small Q XPCS (Station 8-ID-I) • (Limited) Large Q XPCS, liquid surface XPCS (Station 8-ID-E) • Currently, one of 2 such facilities in the world • Develop and apply Grazing Incidence Small-Angle X-Ray Scattering (GISAXS) to study the structure and ordering kinetics of thin films (8-ID-E) • “High-end” SAXS (Station 8-ID-I) • Coherent diffraction imaging (Station 8-ID-I)

  6. Mono or Pink beam 8-ID-I Small-angle XPCS 8-ID-D Undulator A 65 m 8-ID-E 0 m Mono beam 8-ID-A FOE “G” “E” GISAXS large Q XPCS 30 m 51 m Implementation • Beamline 8-ID is a minimalist undulator beamline • Minimal optics for coherence preservation • Minimal diagnostics because of legacy cost considerations • First and second optics enclosures: 8-ID-A and 8-ID-D • Experiment stations: 8-ID-E and 8-ID-I • Primary features • Simultaneous experiment operations in 8-ID-E and 8-ID-I via beam-splitting monochromator in 8-ID-D • Pinhole and mirror in 8-ID-A to reduce downstream power load

  7. Implementation • 8-ID (ongoing) design requirements • Preserve delivered coherence • Provide extremely stable and reproducible coherent x-ray beam to experimenters • (Fully utilize delivered coherence) • Requirements achieved by • Minimizing number of optical components • Minimizing power loading • (Implementing vertical focusing)

  8. Mono or Pink beam 8-ID-I Small-angle XPCS 8-ID-D 2X Undulator 65 m 0 m GISAXS, large Q XPCS 8-ID-A FOE Mono beam 8-ID-E 30 m 51 m Implementation • Radiation Source • High beta straight section • 1-σ source sizes (σ) 270 m (H) × 9 m (V) • 1× Undulator A (72-pole by 3.3 cm = 2.4 m device in 5 m straight) • Transverse Coherence Lengths • ξ = λR/(2πσ) →  7 m (H) × 200 m (V) • Low-beta [σ = 120 m (H)] operations possible and will be examined during upcoming operations cycles • 5 m straight section allows tandem undulator in the future

  9. PINHOLE APERTURE and DIFFERENTIAL PUMP Implementation • First Optics Enclosure 8-ID-A • Windowless connection to APS front end • Used by  40% of APS ID beamlines with no operational issues over past 10 years • Preserves beam brilliance • Pinhole aperture • 300 m exit diameter tapered pinhole greatly reduces transmitted power without sacrificing useful coherent flux • Incident power 1600 watts, transmitted power 5–10 watts (typ.) • Enables small, water-cooled optical components farther downstream

  10. Implementation • First Optics Enclosure 8-ID-A • Horizontally-deflecting 12-cm-long side bounce mirror • Currently most problematic component in the beamline with respect to preserving the source • Small size allows “cheap” replacement as optics fabrication capabilities improve

  11. Implementation • Secondary Optics Enclosure – 8-ID-D • Horizontal, single-bounce ESRF-designed and -built monochromator • Effectively fixed energy operation: 7.35 keV • New crystal holder to eliminate vacuum-water connection allowing eventual removal of upstream Be window • Increased stability and brilliance via better cooling and new connections to 8-ID-E experiment set-ups MONOCHROMATIC BEAM TO E STATION (GISAXS) “E” Si(220) “G” Si(111) Si(111) or Si(220) PINK BEAM FROM FOE PINK BEAM TO I STATION (XPCS)

  12. Liquid Surface XPCS Implementation Large Q XPCS • Experiment Station 8-ID-E • GISAXS dominates user program • Large Q XPCS and liquid surface XPCS • Require additional user support Courtesy Oleg Shpyrko, UCSD

  13. Implementation Brilliance-preserving monochromator* *S. Narayanan et al., J. Synchrotron Rad. 15, 12 (2008) • Experiment station 8-ID-I • Transmission XPCS • Viscous surface XPCS • SAXS • CXDI Re-engineered SAXS set-up • Measured stability increases • Optical contrast doubled per 2003 values

  14. F. Livet, F. Bley, F. Ehrburger-Dolle, I. Morfin, E. Geissler, M. Sutton, "X-ray intensity fluctuation spectroscopy by heterodyne detection," J. Synchrotron Rad. 13 (6), 453-458 (2006). O. G. Shpyrko, E. D. Isaacs, J. M. Logan, Yejun Feng, G. Aeppli, R. Jaramillo, H. C. Kim, T. F. Rosenbaum, P. Zschack, M. Sprung, S. Narayanan, and A. R. Sandy; "Direct measurement of antiferromagnetic domain fluctuations," Nature 447, 68 Scientific and General User Program • Many recent high-impact XPCS results obtained at 8-ID B. Chung, S. Ramakrishnan, R. Bandyopadhyay, D. Liang, C.F. Zukoski, J.L. Harden, R.L. Leheny, "Microscopic Dynamics of Recovery in Sheared Depletion Gels," Phys. Rev. Lett. 96 (22)

  15. Scientific and General User Program • From last 8-ID sector review (9/2006):“…. I was personally well aware of the very positive direction for Sector 8, but it is particularly nice to have it externally recognized, and especially to hear the scientific impact so highly valued. ….” Murray (Gibson, ALD Director) • Respectable XPCS-specific publication rate – the majority of which are published in high-impact factor (impact factor ≥ 5) journals

  16. Scientific and General User Program • 80% of beamtime now allocated through the APS program • Concomitant increase in GU publications • For CY 2007, 8-ID XPCS-time allocated/used as follows: (infrastructure and/or FTE-limited) (infrastructure and/or FTE-limited)

  17. Scientific and General User Program • 8-ID regular and semi-regular General Users (GU’s) • Italics indicate new GU’s since 2003-APS XOR Operations

  18. Scientific and General User Program • For CY2007, XPCS experiment outcomes were roughly as follows: • Estimate that (partially) successful experiments run, on average, ~ 3–4 cycles at 18 shifts per cycle before “complete” • Current over-subscription rate for 8-ID is ~ 40%

  19. Scientific and General User Program • 8-ID, via simultaneous experiment station operations, supports nearly a full end-station complement of XPCS experiments as well as supporting several additional unique experiment capabilities (for various reasons) TR-SAXS from supercritical condensates Partial reconstruction (S. Lin and C. Carter, WPAFB) CXDI from de-alloyed AgAu particle (X. Xiao and Q. Shen, ANL)

  20. Scientific and General User Program • Despite simultaneous station operations, several intimately and peripherally related programs remain under-developed at 8-ID because of lack of: • Beamtime • FTE’s • Infrastructure • Under-developed coherence-related programs at 8-ID include • Large Q XPCS • Liquid surface XPCS • Hard x-ray coherent x-ray diffraction imaging (CXDI) • Transmission small-angle XPCS could grow significantly as well • Aggressive outreach efforts are limited by the lack of available beamtime • There remains significant room for growth in the field of XPCS!

  21. * Opportunities for Improvement • Despite ubiquitous XPCS phase diagram to the contrary, XPCS experiments to-date have been restricted to lower left corner of theoretically accessible phase space *Graphic courtesy of A. Robert, SLAC • Access to larger wave-vector transfers and/or higher frequencies requires brighter sources like NSLS-II and better utilization of the coherent flux delivered by 3rd generation sources

  22. Opportunities for Improvement • Today, in order to remain in the diffraction limit, only 10% of the coherent flux delivered by the undulator is used for 8-ID XPCS experiments • The vertical coherence length is too large • Brilliance-preserving vertical focusing allows the vertical coherence length to be tailored so that the entire coherent flux can be used • XPCS signal-to-noise ratio considerations show that 100× faster dynamics or 10× weaker scatterers can be studied XPCS today XPCS “tomorrow”

  23. Sample K. Evans-Lutterodt et al., Opt. Express 11, 919 (2003) Opportunities for Improvement • Vertical focusing at NSLS-II can be effectively implemented via kinoform lenses • Currently examining lens with the following properties: • Efficiency  50% at 7. 35 keV • 1-σ focal line width = 0.9 m (0.8 m ideal) • 1.04 m focal length (0.97 m ideal)

  24. Opportunities for Improvement 27 m × 20 m (V×H) unfocused 200 m × 20 m (V×H) unfocused 200 m × 20 m (V×H) focused Qy (nm-1) Qx (nm-1) ×1 ×0.1 ×0.2

  25. Opportunities for Improvement 27 m × 20 m (V×H) unfocused 200 m × 20 m (V×H) unfocused 200 m × 20 m (V×H) focused Qy (nm-1) Qx (nm-1) Spatial Autocorrelation:

  26. Opportunities for Improvement • End station design needs to be included in the beamline design process • Number and best type of staffing for beamlines needs to be considered carefully • At APS 3 beamline scientists and 0.5 of a scientific associate support 2 simultaneously operating beamlines at 8-ID • Many recent GU’s have very little scattering background • Increased staffing is an obvious remedy but serious thought should be given to the type of staff especially with more specialized “static” beamlines • Operations manager per ESRF • Beamline scientists provide more strategic support and user recruitment per neutron facilities • Scientific associates • Scientific computing support

  27. Challenges • Competition for both quality GU’s and quality beamline staff from nascent 3rd and 4th generation XPCS facilities and existing 3rd generation facilities • SLS, Diamond, Petra-III • Enhanced brightness and/or sophisticated detector programs • LCLS and XFEL • Different kettle of fish • APS and ESRF • Fully operational with significant upgrade plans/possibilities • Detectors! • Powerful detectors are needed to effectively utilize increased coherent flux

  28. 8-ID Help Wanted

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