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LCLS Instrument Development

LCLS Instrument Development. John Arthur SLAC. from the Charge to the Workshops. In each of the four identified science areas establish a priority list of desired user experiments...

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LCLS Instrument Development

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  1. LCLS Instrument Development John Arthur SLAC

  2. from the Charge to the Workshops • In each of the four identified science areas establish a priority list of desired user experiments... • Identify important x-ray beam parameters to address the envisioned science opportunities, such as photons per pulse, pulse length, 120-Hz-based pulse trains, bandwidth and spectral purity, polarization, coherence…

  3. this talk • LCLS FEL sources • LCLS instrument capability • LCLS facility layout An attempt to enable the discussion of exciting experiments by presenting some basic boundary conditions and ideas that have already been put forward concerning:

  4. LCLS growth • LCLS has a growth plan stretching at least until 2025 • LCLS II Project will provide the infrastructure to enable growth • Anticipate that LUSI II will provide several new instruments • Growth beyond LUSI II will occur as opportunities arise • The goal for 2025 • 4 FEL sources, all or most seeded • At least 10 experimental stations • Ability to run many stations simultaneously

  5. LCLS sources

  6. Basic LCLS source considerations • LCLS complex can support 4 FEL undulators • One exists at LCLS I • Two will be added with LCLS II • A fourth could be added at LCLS I • LCLS I and LCLS II can both reach >10 GeV electron energy • LCLS I can reach 14.5 GeV (>20 GeV with future upgrade) • LCLS II is limited to 13.5 GeV • Space exists for all undulators to become seeded FEL sources • Undulators generally start as SASE sources and can be upgraded

  7. FEL self seeding FEL amplifier (exponential intensity gain) Intense x-ray source with spiky spectrum Additional amplification (linear gain) Monochromator filter creates seed with controlled spectrum seeded Intensity SASE Photon energy

  8. Evolution of an FEL undulator 250 pC 8 keV 2.1 mJ 0.47% bw Add undulators to reach saturation: LCLS-II HXR w/ Self Seeding Mono: LCLS-II HXR BASE Line: Drift 167.2m Drift 140.8m Drift 171.6m Tapered 12-26 66.0m S.S. 1-11 48.4m SASE 1-26 114.4m Tapered 12-32 92.4m 167.2 140.8 215.6 171.6 189.2 286.0 286.0 286.0 0 0 0 40 pC 8 keV 2.6 mJ 0.05% bw S.S. 1-11 48.4m Mono 4.4m Mono 4.4m 220.0 S.S. Virtual Source Point 251-256m 40 pC 8 keV 4.8 mJ 0.05% bw S.S. Virtual Source Point 232-237 SASE Source Point 246-261m Full build out, additional tapered undulators: 193.3 40 pC 8 keV 8.3 mJ 0.04% bw S.S. 1-14 61.6m Tapered 15-64 220.0m Mono 4.4m 0 286.0 61.6 66.0 S.S. Virtual Source Point 178-183 M. Rowen

  9. Polarization control can be added LCLS-II SXR BASE Line: Drift 13.2m Drift 206.8m SASE 1-15 66.0m 272.8 286.0 206.8 0 SASE Source Point 247-257m Mono 8.8m Full build out, tapering and Polarization Control: Drift 132.0 S.S. 1-9 39.6m Tapered 10-30 92.4m 3 Pol. 13.2m 171.6 180.4 132.0 0 286.0 272.8 S.S. Virtual Source Point 222-227 M. Rowen

  10. LCLS SASE source characteristics 250pC bunch charge 70m SXR undulator 110m HXR undulator LCLS II SXR 13.5 GeV LCLS II SXR 8.5 GeV LCLS II HXR 13.5 GeV LCLS I 3.3-15 GeV LCLS I and LCLS II together provide complete coverage from 250eV to nearly 20keV with >1mJ pulses LCLS II HXR 8.5 GeV

  11. LCLS seeded source characteristics 100 Seeded SXR 10 HXR Energy per pulse (mJ) 1 SASE 100pC, 110m SXR undulator 50pC, 250m HXR undulator Large uncertainties in seededoptimization and sensitivity 0.1 10 0.1 1 Photon Energy (keV)

  12. Conclusions about FEL sources • Seeded sources are generally better • Generally give more pulse power,much higher peak power • Narrow, predictable bandwidth • But, single-bunch seeding is limited to lower-charge short bunches (a two-bunch seeding scheme might overcome this limitation) • LCLS facility will cover a wide photon energy range • LCLS II baseline spec is 250 eV to 13 keV • Expect actual useful range to extend to near 20 keV or above • Much of the range can be covered with one fixed electron energy

  13. LCLS instrument capability

  14. Proposed definitions The term “beamline” can be confusing when used in a context with sources, transport, and optical components serving multiple experimental stations. It may help to focus the discussion on the following: • Beam Transport – transmits X-rays from source to end station • May service more than one end station • Optics elements may be distributed along the beam transport • Optics – redirect and condition the X-rays on the way from source to end station • May service more than one end station • End Station – includes sample environment and detectors • May be permanent or removable (roll-in/roll-out)

  15. LCLS instruments are becoming more complex • LCLS has 6 hutches now, with 1 source • AMO, SXR have multiple, removable end stations • CXI is developing a system of 2 in-line end stations • Could eventually allow simultaneous experiments • LCLS is developing beam-splitting technology • In near future, expect to deliver beam to several end stations simultaneously Currently the source feeds only 1 end station at a time but

  16. More complexity coming • LCLS II adds 2 new FEL sources • LCLS II adds room for at least 4 new end stations • Could squeeze in additional end stations • LCLS I has room for an additional undulator • More capability for simultaneous operations

  17. A fundamental change in LCLS operation • LCLS available beam time will dramatically increase • Source flexibility may decrease • Multiple experiments on one source must agree on parameters Consequences of LCLS expansion/multiplexing:

  18. How to best manage the expansion? • Start with the science • A clear vision of science opportunities • An understanding of the instrumentation that the science requires • Develop concepts of instruments for doing the science, including source parameters, optics and diagnostics, end stations • Optimize the design and layout of the instruments

  19. Information to be captured from discussions during and after this workshop

  20. Possible biology instrumentation • High peak power hard X-ray imaging/diffraction instrument • With lasers for pumping, various sample environments, fluorescence spectrometers • With 2 end stations in series for simultaneous operation • High peak power intermediate-energy X-ray imaging instrument • 2-6 keV photon energy • With lasers, sample environments, spectrometers

  21. Possible materials/chemistry instrumentation • General purpose hard X-ray scattering instrument • With various sample environments, detector resolutions, geometries, monochromator, detectors, focusing, split & delay, optical pump lasers, etc… • For WAXS, SAXS, XAS, XES, coherent scattering, etc… • Soft X-ray instrument with polarization control • With several end stations optimized for diffraction, RIXS, surface science, etc… • With pump laser capability over wide spectral range including THz

  22. Possible AMO instrumentation • Seeded source with narrow bandwidth, high power • Branches optimized so user can choose either high energy resolution or high peak power • Multiple end stations accommodating various sample sources and spectrometers • Gas jets, cluster sources ovens, laser ablation sources, ion sources • Ion and electron spectrometers including magnetic bottle, high energy resolution, and angle resolving spectrometers • X-ray spectrometer • Lasers for time-resolved experiments • Diagnostics for spent X-ray beam

  23. Layout of the LCLS complex DOE CD-3a Review of the LCLS-II Project, Dec 6-7, 2011 Slide 23

  24. Fitting 4 experiment stations in EH2 Hard X-ray Soft X-ray

  25. Fitting 6 experiment stations in EH2 Hard X-ray Soft X-ray

  26. Summary • LCLS has an ambitious expansion plan and the LCLS II project is a critical enabling step • LCLS should start now to work out the details of the expansion plan in anticipation of funding opportunities • This workshop will help to define the first step, a package of instruments to be installed at LCLS II • The details start with the science, which then defines the source and instrument requirements

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