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John Corlett Center for Beam Physics For the LBNL next generation light source working group

Next Generation Light Source Outline and R&D Plans. John Corlett Center for Beam Physics For the LBNL next generation light source working group X-Ray FEL Workshop LBNL October 23, 2008. LBNL is Developing Concepts for a High-Repetition Rate, Seeded, VUV - Soft X-ray FEL Facility.

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John Corlett Center for Beam Physics For the LBNL next generation light source working group

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  1. Next Generation Light Source Outline and R&D Plans John Corlett Center for Beam Physics For the LBNL next generation light source working group X-Ray FEL Workshop LBNL October 23, 2008

  2. LBNL is Developing Concepts for a High-Repetition Rate, Seeded, VUV - Soft X-ray FEL Facility • Array of ~10 configurable FELs, each up to 100 kHz bunch rate • Independent control of wavelength, pulse duration, polarization • Each FEL configured for experimental requirements; seeded, attosecond, ESASE, etc Beam Phase-space manipulation Beam transport and switching CW superconducting linac 2.5 GeV, 13 MeV/m Low-emittance, MHz bunch rate photo-gun ≤ 1 nC ≤1 mm-mrad Laser systems, timing & synchronization ~700 m

  3. Spectrum Pulse profile Seeded FELENHANCED CAPABILITIES FOR CONTROL OF X-RAY PULSE SASE 25 fs seed Seeded FEL close to transform limit 500 fs seed Electron beam is 1.5 GeV, energy spread 100 keV, 250 A current, 0.25 micron emittance; laser seed is 100 kW at 32 nm; undulator period 1 cm

  4. Performance Goals FELs WITH THREE PRINCIPAL MODES OF OPERATION Ultrafast time domain - extended to sub-femtosecond High-resolution spectral domain - extended intrinsically to meV Polarization control, tunability, parallel operation of multiple beamlines Address needs for revolutionary spatial, energy, and time resolution Requires superconducting accelerator and laser manipulation of electrons High average x-ray power - extended to watts High x-ray pulse repetition rate - extended to 100 kHz

  5. ALS is the Premier VUV–SXR Facility Worldwide – FEL Provides for Electron Dynamics in VUV–SXR

  6. One of the Possible Tunnel & Beamline Configurations FEL array and X-ray beamlines ALS Injector Accelerator & beam transport in tunnel

  7. LDRD Supports Critical Accelerator R&D Emittance manipulation and beam conditioning FEL concepts High repetition-rate electron gun High-brightness photocathodes

  8. Injector defines the minimum beam emittanceINTEGRATED SYSTEMS: CATHODE, LASER, ACCELERATING SECTIONS Integrated systems Low emittance, high quantum efficiency cathodes Photocathode laser systems including pulse shaping Acceleration technologies Normal conducting RF Superconducting RF DC gun

  9. High Brightness Photocathodes EXPERIMENTAL, THEORY AND MODELING PROGRAM • Goals: • - Fundamental understanding of the properties of photocathodes • - Design of optimum materials for photocathodes • Reduce emittance • Increase efficiency • Experimental program: • Photoemission Lab • Angle-resolved photoemission spectroscopy • Theory & modeling program: • Stochastic heating studied using Barnes-Hut tree method • Direct N-body model Howard Padmore, Weishi Wan, Christopher Coleman-Smith, Ji Qiang

  10. 5 axis manipulator; motor scanned theta, LN2 – 1100 K Low Energy Electron Diffraction + Auger Tunable 2nd, 3rd, 4th harmonic generation + pulse picker Time of Flight Electron Analyzer Sample transfer VIS UV mono 80 MHz Ti:S Oscillator Photocathodes Lab: Building 2 - 457 Howard Padmore

  11. Cu(111): A Typical Metal Cathode Low energy reflectivity, electron yield, electron momentum ARPES shows emission mainly from surface states - more above s-p band gap - above s-p band gap Pedersoli et al, accepted for APL photon energy: 5.71 eV - at s-p band gap Howard Padmore E. Pedersoli

  12. Design for a CW, VHF Photogun HIGH BUNCH RATE, ACCOMODATES VARIED CATHODE MATERIALS Fernando Sannibale John Staples Russ Wells Vacuum pumps in plenum Cathode insertion & withdrawal channel (mechanism not shown) Vacuum pumping slots Cathode Beam exit aperture

  13. Design for a CW, VHF Photogun T-M Huang John Staples 187 MHz compatible with both 1.3 and 1.5 GHz SC accelerating sections

  14. APEX - Advanced Photoinjector EXperiment R&D proposal submitted to DOE BES CW accelerating cavity Cathode mounted on coaxial support Laser beam Beam transport and diagnostics • New LDRD award in FY09 supports • Cavity design & fabrication • Specification & build of VHF power supply

  15. APEX Phase-IGun, Cathode & Laser Tests in the BTF BTF cave VHF cavity Beam dump Diagnostics beamline

  16. APEX Phase-Ib CW VHF PHOTO-GUN, RF BUNCHING, SCRF INJECTOR LINAC Beam diagnostics Buncher cavity CW VHF photo-gun Beam dump Superconducting injector linac cryomodule Build expertise and demonstrate injector beam performance

  17. APEX Phase-Ib CW VHF PHOTO-GUN, RF BUNCHING, SCRF INJECTOR LINAC APEX Phase-Ib in the Beam Test Facility

  18. D D D D F F F F D D F F 466 150 kicker kicker kicker septum septum F 2000 10800 200 Baseline Machine Design Under Development CW VHF photo-gun cavity MHz bunch rate 20 MV/m at cathode ~10-11 Torr Injector with CW SCRF linac Lattice design to optimize performance Tunnel and engineering concepts developed Beam switchyard with fast kickers 3 mrad, 100 kHz Sasha Zholents Bill Fawley Gregg Penn Ji Qiang Fernando Sannibale Marco Venturini Russ Wells

  19. High resolution modelingREVEAL THE TRUE PHYSICS OVER NUMERICAL NOISE Microbunching instability arises from shot noise in the electron beamSimulated with LBNL code IMPACT109 macro-particles 2000 processors, 3 hours ∆E/E Sasha Zholents Marco Venturini Ji Qiang I. Pogorelov Red – 107 macro-particles Green– 109 macro-particles Blue - no space charge effects t (ps) Value of f is determined by interpolation using values of f on adjacent grid points Another approach- Vlasov solver Advance beam density function using transfer maps M. Venturini, R. Warnock, and A. Zholents, “Vlasov solver for longitudinal dynamics in beam delivery systems for x-ray free electron lasers” Phys. Rev. ST Accel. Beams 10, 054403 (2007)

  20. Improved Understanding of Collective Effects Development of Advanced Computational Tools Before the second bunch compressor After the first bunch compressor ∆E (MeV) z (mm) After the second bunch compressor Sasha Zholents Marco Venturini Ji Qiang Reliable calculation including shot noise - note spatial structure scale ~1µm

  21. Optical manipulations techniques (1) ESASE SASE Bunching Modulation Acceleration 20-25 kA Peak current, I/I0 z /lL • Precise synchronization of the x-ray output with the modulating laser • Variable output pulse train duration by adjusting the modulating laser pulse • Increased peak current • Shorter x-ray undulator length to achieve saturation • Capability to produce a solitary ~100-attosecond duration x-ray pulse • Other techniques can be used to produce controlled x-ray pulses A. Zholents, Phys. Rev. ST Accel. Beams 8, 040701 (2005)

  22. Optical manipulations techniques (2) HHG LASER SEED Example with seed at 30 nm, radiating in the water window First stage amplifies low-power seed with “optical klystron” More initial bunching than could be practically achieved with a single modulator Output at 3.8 nm (8th harmonic) 100 kW l=30 nm Radiator l=3.8 nm, L=12 m Modulator l=30 nm, L=1.8 m Modulator l=30 nm, L=1.8 m 1 GeV beam 500 A 1.2 micron emittance 75 keV energy spread 300 MW output at 3.8 nm (8th harmonic) from a 25 fs FWHM seed Lambert et al., FEL04 M. Gullans, G. Penn, and A.A. Zholents, “Performance study of a soft X-ray harmonic generation FEL seeded with an EUV laser pulse”, Optics Communications274, 167-175 (2007)

  23. Optical manipulations techniques (3) ATTOSECOND HARD X-RAY PULSES 1.5Å output pulse Energy modulation with two lasers (1.2, 1.6 µm) ~ 100 as A.Zholents, W.M. Fawley, Phys. Rev. Lett. 92, 224801 (2004) A.Zholents, G. Penn, Phys. Rev. ST Accel. Beams 8, 050704 (2005)

  24. Spreader design: beam take-off section 3 m Scale: F D F D F D F D F D kicker 0.2 m kicker kicker sep-tum sep-tum 15 cm 27 mrad 3 mrad 15.6 mm connector & cable option Sasha Zholents Eugene Kur Russ Wells Distance between orbits at the beginning of a septum Kicker: 2 m long stripline, 15 kV/cm; can accommodate magnet on top

  25. Timing & Synchronization Systems Faraday rotator 50% mirror temp. control, 0.01C piezo, mirror delays 1530nm +55MHz km fiber CW fiber laser freq. shifter P f1 output f1 + 110MHz ref. arm C2H2 freq. locker 110MHz beat 2 mixer 110MHz oscillator SYNCHRONIZATION FOR PUMP-PROBE EXPERIMENTS • Interferometric phase delay controller • Measured jitter 0.25 fs RMS, 10Hz to 40MHz • Measured drift 3 fs over 10 hours • Integrated with laser oscillator/LLRF/controls Prototype systems under test at LCLS, will also be delivered to FERMI@Elettra John Byrd Russell Wilcox John Staples Gang Huang

  26. High-Power Laser Development - Q-Peak awarded STTR CRYO-COOLED YT:YAG 4mm THICK CRYSTAL SLAB ~200-300 W @ ~1 µm, 0.1–1.0 MHz

  27. Thanks to an Excellent Team - Contributions From Many Divisions Within LBNL Bill McCurdy Pat Oddone Howard Padmore Gregg Penn Ji Qiang Alex Ratti David Robin Kem Robinson Glenna Rogers Fernando Sannibale Bob Schoenlein John Staples Christoph Steier Will Waldron Weishi Wan Russell Wells Russell Wilcox Sasha Zholents Max Zolotorev Walter Barry Ali Belkacem John Byrd John Corlett Rick Donahue Larry Doolittle Roger Falcone Bill Fawley Tom Gallant Steve Gourlay Zahid Hussein Preston Jordan Janos Kirz Jim Krupnick Eugene Kur Slawomir Kwiatkowski Steve Leone Derun Li Steve Lidia Tak Pui Lou

  28. Science case development • Workshop report “Toward Control of Matter: Basic Energy Science needs for a New Class of X-ray Light Sources” • White paper “Scientific Needs for Future X-ray Sources in the U.S.” • Future FEL facility technology development is a component in the Leone EFRC proposal “Ultrafast X-ray Spectroscopy of Energy-Harvesting Systems

  29. High-gain harmonic generation (HGHG) 795-199 nm DEMONSTRATED AT BROOKHAVEN SDL L.-H. Yu et al, Phys. Rev. Let. Vol 91, No. 7, (2003) X.-J. Wang, ICFA Beam Dynamics Newsletter N0. 42, (2007) http://www-bd.fnal.gov/icfabd/Newsletter42.pdf

  30. Conceptual Design Study from Jacobs Associates

  31. Summary • Science case development • Workshop identified major themes • Planning for small workshops in key areas • Working with SLAC and others to identify the National needs for future x-ray facilities • R&D in critical technologies • Photo-cathode design • RF photo-gun design • Low-emittance beam transport & beam dynamics • FEL design • Participation in FEL construction projects is building expertise • LCLS • FERMI@Elettra • Workshops and meetings held to further understanding in key areas • Science case • Tunnel engineering • High power laser systems • Microbunching in FELs • X-ray FEL R&D LBNL OCTOBER 23-25, 2008 http://www-afrd.lbl.gov/xrfel/X-RAY_FEL_WORKSHOP.html • Planning for future construction project • Design of a skeleton facility is under way • Preparing machine design to be at the level of CD0 in FY09 • Coordinating with other institutions, notably SLAC

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