In collaboration with Winthrop Brown, T.Y. Fan, Franz Kaertner, Integrating Laser and Linac Technology for Next Generation X-ray Sources William S. Graves MIT September 11, 2008 Alghero, Sardinia In collaboration with Winthrop Brown, T.Y. Fan, Franz Kaertner, and David Moncton

MIT Inverse Compton Source Concept Yb:YAG Pre amp Yb:YAG Osc pump diode SESAM Multi-passYb:YAG Amplifier 4 m Superconducting linac operating at 325 MHz and 4K Diodes ¼-wave SRF injector RF amp RF amp RF amp ≤50 MeV electron beam x-ray detectors Pulse shaping 4th harmonic generation Collimating chicane Tunable x-ray optics RF IOT Yb:YLF Amplifier 8 m

Laser Technology Oscillator or Osc./Amp. combination Electron beam X-ray beam Continuous 10mJ operation Cryo-cooled Yb:YAG multi-pass amplifier 1ps, 100mJ, 10 MHz 1kW 1 m Yb:YAG 1 ps, 1mJ, 10 MHz, 10W Oscillator or Osc./Amp. combination

200 W cryo-cooled Yb:YAG T.Y. Fan group at Lincoln Lab Polarizers L N2 dewar Multi-pass cell Output coupler & AOM Polarizers Fiber head for diode pump Photodiode T.Y. Fan group at Lincoln Lab

Brightness and Flux scale dramatically with the electron beam quality: ICS Optimization Brightness and Flux scale dramatically with the electron beam quality: Flux Peak Brightness Avg Brightness

Dependence on Electron Beam Focus Electron Beam Parameters (25 MeV) Emittance = 0.7 mm-mrad Q = 0.1 nC (S2E Case) Rms Duration = 2.1 ps Laser Parameters l = 1 mm W = 10 mJ Rms Duration = 0.5 ps Performance vs. Laser Spot Size for Different Electron Beam Focus Sizes 10 20 30 40 2 4 6 8 x 10 Rms Laser Spot Size (microns) Total X-ray Dose 2.175 microns 4.35 microns 6.525 microns 8.7 microns 10.875 microns 10 20 30 40 5 15 x 10 Rms Laser Spot Size (microns) Avg. Brightness/Rep. Rate 2.175 microns 4.35 microns 6.525 microns 8.7 microns 10.875 microns

Full Calculations of the Photon Spectrum Time dependent, 3D code developed at LLNL for linear regime Normalized emittance = 0.3 mm Normalized emittance = 1.0 mm 10 0.1 0.01 100 photons/mrad2/eV 1 photons/mrad2/eV 10 0.1 0.01 1 Note: Plane Perpendicular to Laser Polarization

Dependence on Electron Bunch Duration Electron Beam Parameters en = 0.7 mm-mrad (25 MeV) Rms spot size = 4.3 mm Q = 0.1 nC Laser Parameters l = 1 mm W = 10 mJ Pulse duration = 0.5 ps 5 10 15 20 2 4 6 8 12 x 10 Rms Laser Spot Size (microns) Total X-ray Dose 0.125 ps 0.25 ps 0.5 ps 1 ps 2 ps 5 ps 10 ps 5 10 15 20 2 4 6 8 x 10 Rms Laser Spot Size (microns) Avg. Brightness/Rep. Rate 0.125 ps 0.25 ps 0.5 ps 1 ps 2 ps 5 ps 10 ps

Intensity Profile of 12 keV X-rays with 0.1% bw Emittance = 0.7 mm-mrad Photons/sec = 8 x 1010 @10 MHz

X-ray Source Performance Comparison Peak Brilliance Brilliance Flux ‘Ideal’ XFEL 1 x 1035 1 x 1028 5 x 1016 APS 8 x 1022 5 x 1019 8 x 1014 SRF Linac ICS 4 x 1017 2 x 1013 8 x 1010 SR ICS 4 x 1013 5 x 1010 2 x 1010 NC Linac ICS 1 x 1020 1 x 1010 1 x 108 Rotating Anode 4 x 1010 4 x 1010 4 x 109 Note: All numbers are in units of 0.1%BW

Summary ICS flux and brightness depend on electron beam current and emittance (just like a synchrotron source!) SRF accelerator combined with high average power laser can generate optimal beam parameters for best flux, peak and average brightness ICS parameters much better than existing home sources but still less than big synchrotrons ICS outperforms big synchrotrons in ultrafast x-ray performance, and is competitive in level of coherence Cost of ICS source similar to 3rd gen beamline: ~$10M