1. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory LCLS Scientific Program X-Ray Laser Physics: Advanced R&D J. B. Hastings Brookhaven National Laboratory February 26, 2001 Focusing of X-Ray Pulses Generation Shorter X-Ray Pulses Increase of Longitudinal Coherence Focusing of X-Ray Pulses Generation Shorter X-Ray Pulses Increase of Longitudinal Coherence

2. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Working Group Members J. B. Hastings, Brookhaven National Laboratory, Upton, NY, USA J. Arthur, Stanford Linear Accelerator Center, Stanford, CA, USA P. Emma, Stanford Linear Accelerator Center, Stanford, CA, USA A. Freund, European Synchrotron Radiation Facility, Grenoble, France D. Mills, Argonne National Laboratory, Argonne, IL, USA C. Pellegrini, University of California, Los Angeles, CA, USA D. Peter Siddons, Brookhaven National Laboratory, Upton, NY, USA R. Tatchyn, Stanford Linear Accelerator Center, Stanford, CA, USA A. Toor, Lawrence Livermore National Laboratory, Livermore, CA, USA L.-H. Yu, Brookhaven National Laboratory, Upton, NY, USA J. B. Hastings, Brookhaven National Laboratory, Upton, NY, USA J. Arthur, Stanford Linear Accelerator Center, Stanford, CA, USA P. Emma, Stanford Linear Accelerator Center, Stanford, CA, USA A. Freund, European Synchrotron Radiation Facility, Grenoble, France D. Mills, Argonne National Laboratory, Argonne, IL, USA C. Pellegrini, University of California, Los Angeles, CA, USA D. Peter Siddons, Brookhaven National Laboratory, Upton, NY, USA R. Tatchyn, Stanford Linear Accelerator Center, Stanford, CA, USA A. Toor, Lawrence Livermore National Laboratory, Livermore, CA, USA L.-H. Yu, Brookhaven National Laboratory, Upton, NY, USA

3. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Photons/pulse/100 nm spot Landscape of damage tolerance Ionisation and subsequent sample explosion cause diffraction intensities to change Agreement factor: Time (fs) Crystallographic R-factor for proteins in the PDB

4. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Calculated limits of resolution with R electronic = 15 % Limit with 1 photon/pixel Limit with 9 photons/pixel

5. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Temporal and Spatial Scales Time in femtoseconds, distance in Å H 2 O  OH + H CH 2 I 2  CH 2 I + I

6. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Shortest Fundamental FEL Radiation Wavelength1.5Å Electron Beam Energy14.3GeV Normalized RMS Slice Emittance 1.2mm-mrad Peak Current3.4kA FEL Mode Source Size (FWHM)78  m FEL Mode Source Divergence (FWHM)1  rad Peak Brightness *1210 32 X-Ray Pulse Length (FWHM)230fs Average Time Between Micro-Pulses0.9fs Average Full width of Micro-Pulses0.2fs Average Number of Micro-Pulses in Pulse250 Transverse CoherenceFull Slice Bandwidth 510 -4 Projected Bandwidth 210 -3 * photons/sec/mm 2 /mrad 2 /0.1%-BW LCLS Baseline Design Parameters

7. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Focusing of LCLS Pulses Focusing is singularly important phase space transformation of the LCLS pulse Available Field Strengths ~10 10 V/m  10 16 V/m Proposed R&D in six areas critical to Reflective, Diffractive and Refractive focusing Focusing is singularly important phase space transformation of the LCLS pulse Available Field Strengths ~10 10 V/m  10 16 V/m Proposed R&D in six areas critical to Reflective, Diffractive and Refractive focusing Beam Diameter ~100  m -> ~100 nm X-ray field 5x10 17 W/cm 2 exceeds atomic unit: 3.5x10 16 W/cm 2

8. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory SLAC linac tunnel FFTB tunnel Linac-0 Linac-1Linac-2Linac-3 BC-1 BC-2 DL-2 DL-1 undulator L  120 m 7 MeV  z  0.84 mm 150 MeV  z  0.84 mm 250 MeV  z  0.20 mm 4.54 GeV  z  0.024 mm 14.35 GeV  z  0.024 mm...existing linac (8/29/00) new RF gun Linac-X Short-Pulse Generation (Electron Bunch): LCLS Accelerator and Compressor Schematic Courtesy of P. Emma, SLAC X

9. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Short-Pulse Generation (Electron Bunch): Magnetic Electron Bunch Compression  z z z RF Accelerating Voltage Path Length-Energy Dependent Beamline V = V 0 sin(  ) z0z0 zz  z = R 56  Under- compression Over- compression Courtesy of P. Emma, SLAC

10. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory nominal LCLS compression Q = 1 nC chirped compression Q = 0.6 nC 230 fs 240 fs 1% 0.01%  E/E Current Z (  m)

11. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Short-Pulse Generation (X-Ray Pulse): Based on Chirping Chirped X-Ray Pulse Generated from Chirped Electron Pulse in FEL Undulator 1% Chirp Amplitudes Obtainable Optical techniques using the chirped pulse Optical Pulse Compression Optical Pulse Slicing with Zone Plates, Multi-Layers, Crystals Chirped X-Ray Pulse Generated from Chirped Electron Pulse in FEL Undulator 1% Chirp Amplitudes Obtainable Optical techniques using the chirped pulse Optical Pulse Compression Optical Pulse Slicing with Zone Plates, Multi-Layers, Crystals

12. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Optical Compression and Pulse Slicing  Z (t)  Pulse Slicing Pulse Compression  

13. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Optical Pulse Compression Optical pulse compression by energy chirping the photon beam and compressing it with 2 gratings. Example of minimum pulse length: Minimum pulse length:~ 10 fs Wavelength spread:2 % Grating line separations:5.5  m Gratings vert. separation:75 cm Gratings hor. separation:107 m Incident angle at grating:0.2 mrad Grating length:1 m Courtesy of C. Pellegrini, SLAC No Practical Solution has yet been worked out

14. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Optical Pulse Slicing with Crystals Minimum sliced bunch length ~ 10 fs

15. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory SASE FEL theory well developed and verified by simulations FEL radiation starts from noise in spontaneous radiation Transverse radiation electric field modulates the energy and bunches the electrons within an optical wavelength Exponential build-up of radiation along undulator length SASE FELs Undulator Regime Exponential Gain Regime Saturation 0.2 fs 0.9 fs 1 % of X-Ray Pulse Electron Bunch Micro-Bunching

16. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Longitudinal coherence SASE FEL starts up from noise No longitudinal coherence Seeding Impose microbunching of the electron beam Output is the amplified input Preserves the longitudinal coherence of the seed An example: self seeding SASE FEL starts up from noise No longitudinal coherence Seeding Impose microbunching of the electron beam Output is the amplified input Preserves the longitudinal coherence of the seed An example: self seeding

17. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Increase of Longitudinal Coherence : Two Stage FEL Undulator 1 Linac Undulator 2 Monochromator Electrons Electron Beam Dump X-Rays LCLS Spectral Properties Control

18. Basic Energy Sciences Advisory Committee MeetingLCLS February 26, 2001 J. Hastings Brookhaven National Laboratory Summary The LCLS design opens the possibility for adjusting X-Ray beam parameters according to the needs of the experiments. Improvement are with high user interest include –Increased Electrical Field Strength (Focusing) –Shorter Bunch Length (Electron Bunch / X-Ray Pulse Compression,slicing) –Increased Longitudinal Coherence (Seeding / Monochromatization) All areas need extensive R&D Efforts 230 fs -> 50-20 fs 10 10 V/m -> 10 16 V/m Coherence Length: 1 fs -> >100 fs Beam Diameter: ~100  m ->below 100nm  E/E: 10 -3 -> 10 -6