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SLAC UED/UEM Initiative and UED@ASTA

SLAC UED/UEM Initiative and UED@ASTA. Accelerator Directorate Review on UED@ASTA. X.J. Wang- May 20, 2014. Fundamental Probes in the BES. _. Users desire to use different probes to obtain complementary info on samples

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SLAC UED/UEM Initiative and UED@ASTA

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  1. SLAC UED/UEM Initiative and UED@ASTA • Accelerator Directorate Review on UED@ASTA X.J. Wang- May 20, 2014

  2. Fundamental Probes in the BES _ • Users desire to use different probes to obtain complementary info on samples • Electrons & x-rays see electrons and proton, while neutrons can see nuclei

  3. DOE BES Future Electron Scattering and Diffraction Workshop A – Multidimensional Visualization of Real Materials B – Atomic Scale Molecular Processes C - Photonic Control of Emergence in Quantum Materials D - Evolving Interfaces, Nucleation, and Mass Transport • Ultrafast Electron Diffraction and Microscopy Facility B.1 – Source (MeV) and Electron Optics: B.2 - Pump Technology

  4. The UED-UEM initiative at SLAC/Stanford Vision: The SLAC UED/UEM facility will be the world leading electron scattering instrumentation facility, complementary to the LCLS X-ray FEL. The UED/UEM facility will possess unique capabilities that enable Grand Challenge science in chemistry, material science, physics and biology. The availability of intense THz, X-ray and optical laser pumping in conjunction with UED/UEM probes will open new scientific opportunities. electron beam THz

  5. SLAC Lab Agenda (2014) X-Ray THz

  6. SLAC UED/UEM Summary ~48 months (2019) 18 months (2015) 2016 *base design - upgrade - blue sky R&D

  7. Ultrafast (< 10 ps) imaging only possible at higher voltages Point Spread Function at 200 keV, 1 ns Point Spread Function at 5 MeV, 10 ps -50 nm 0 -100 nm 100 nm 50 nm -50 nm 0 -100 nm 100 nm 50 nm For picosecond resolution imaging, relativistic energies may be the only way to obtain high spatial resolution. M. R. Armstrong, B. W. Reed, B. R. Torralva, and N. D. Browning, Appl. Phys. Lett. 90, 114101 (2007).

  8. Large Scattering Signal R.Valleet al, Ultramicroscopy 27, 67 (1989)

  9. Pump-probe Velocity Mismatch ΔtVM> 1ps 60keV UED Ve= 0.446c ΔtVM< 10fs 3MeV UED Ve= 0.989c

  10. Sample Damage • Knock on • Pulse radiolysis • Charging R.F. Egerton et al. Micron 35，399 （2004)

  11. Ultrafast Electron Diffraction (UED) RF Gun MeV-UED BNL TEM Laser OPA / THZ Syn Axicon UV Optics RF Lens Sample Detector • La0.5Sr1.5MnO4: Orbit & Charge Orders

  12. Ultrafast Electron Diffraction (UED) RF Gun & Nano-UED Laser OPA / THZ Syn Axicon UV Optics RF Condenser Lens Sample Detector

  13. Ultrafast Electron Imaging (UEM) RF Gun Laser OPA / THZ Syn Axicon UV Optics RF Condenser Projector Lens Objective Detector Sample

  14. UED @ ASTA? There are three potential sites at SLAC could be considered for the first phase of UED. Those three sites are ASTA, NLCTA and LCLS II injector. • ASTA the most favorable site for fast impact experiments, • Existing RF gun and infrastructure. • Laser system. • Synergy with LCLS cathode R&D – thermal emittance reduction. • X-band for beam diagnostics • Concerns: • Impact to existing program: LCLS cathode R&D, semi-conductor cathode, and X-band testing program • Space and environment (temperature and vibration) • safety (laser and radiation), budget and resource (manpower). • Others

  15. The Accelerator Structure Test Area (ASTA)

  16. UED@ ASTA Objectives FePt • First 100 Femto-second MeV UED at high rep rate • Order of magnitude improvement (120 Hz vs 10 Hz) • MeV UED Ultrafast Science FY14 heat sink 2nm Goal: understand & control materials processes related to heat-assisted magnetic recording • Understand and quantum control of chemical reactions. • Structure of intermediate states

  17. Early Physics: UED@ ASTA (FY14)

  18. Early Physics: UED@ ASTA (FY14)

  19. Challenges in UED @ ASTA • Time and resource • Infrastructure upgrade – ASTA bunker space and laser room air conditioning • Technical challenges: • Electron beam line ( diagnostic, sample chamber and detector) • Laser RF synchronization • Low level RF • Klystron modulator • Laser transport and pump-probe optics

  20. Laser Cathode RF Gun Challenges in MeV-UED - Timing Jitter Timing jitter Δtjitter= RF Oscillator RF Drive Sample

  21. ALD Review on UED@ASTA Agenda Start End Time Title Speaker ​​​8:00 ​​8:30 ​​0:30 Executive session ​ ​​​8:30 ​8:40 ​0:10 ​Welcome and charge to the committee ​ Bob Hettel ​​​8:40 ​9:10 ​0:30 SLAC UED/UEM Initiative and UED@ASTA ​XJ Wang ​​​​9:10 ​​9:30 ​0:20 ​Science enabled by the UED/UEM and early science at ASTA ​Hermann Durr ​​​​9:30 ​​9:50 ​0:20 UED@ASTA project plan and ES&H ​Carsten Hast ​​​​9:50 ​​10:05 ​0:15 ​​UED@ASTA beam line and mechanical layout ​Eric Bong ​10:05 ​​10:20 ​0:15 ​Coffee break ​ ​​10:20 ​​​10:50 ​0:20 ​Beam Dynamics study ​JuhaoWu ​​10:40 ​11:00 ​0:20 ​RF power stability ​ Minh Nguyen ​​​11:00 ​11:20 ​0:20 ​LLRF and timing triggers ​Stephen Weathersby ​​11:20 ​​11:40 ​0:20 ​Laser-RF timing and synchronization ​Joe Frisch ​11:40 ​12:00 ​0:20 UED laser transport and pump-probe optics ​Ryan Coffee ​12:00 ​12:20 ​0:20 UED commissioning ​RenkaiLi ​12:20 ​01:15 ​0:45 ​Lunch and discussion ​ ​01:00 ​01:45 ​0:45 ​ASTA tour ​Bldg. 44 ​01:45 ​03:30 ​2:00 ​Executive session, report preparation + additional questions ​ ​03:00 ​ Coffee ​ ​03:30 ​​04:30 ​0:30 ​Close-out

  22. Summary • The SLAC UED/UEM facility will be the world leading electron scattering instrumentation facility, complementary to the LCLS X-ray FEL. The UED/UEM facility will possess unique capabilities that enable Grand Challenge science in chemistry, material science, physics and biology. The availability of intense THz, X-ray and optical laser pumping in conjunction with UED/UEM probes will open new scientific opportunities. • UED@ASTA will be the first step toward SLAC UED/UEM facility, it will be the first UED breaking 100 fs barrier and enable some exciting science. We have a realistic plan to realize the first experimental in FY 2014.

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