Ultrafast Laser -Driven Wakefield Accelerators Oleg Korovyanko 01/12/2009 SLAC AARD seminar

1. Ultrafast Laser -Driven Wakefield Accelerators Oleg Korovyanko 01/12/2009SLAC AARD seminar

2. Outline Part 1: Wakefield accelerators: techniques to generate short e bunches Part 2: Production of quality electron beams, characterization and applications Part 3: Relevant laser techniques Part 4: Conclusion and perspectives

3. 100 mm Plasma cavity RF vs Plasma E-field max~ 10 MeV /m E-field max~ 10 GeV/m Courtesy of V. Malka 1 m RF cavity DWA Diel. surface field breaks down @~ 10 GeV/m

4. Argonne Wakefield Accelerator1.3 GHz, TSA 50

7. > 1.6 W @ 400 nm SHG2 SHG1 FS D3-4 IR4 D1 D2 IR1 WP SHGxtal THGxtal > 900 mW @ 266nm IR2-3 Prepared by DSF2059, 031307, RLS

8. ANL AWA1.3 GHz, TSA 50 • Built as DWA: witness, drive bunches • Two 248nm pulses go to photocathode of RF gun, one or several drive bunches inter-pulse separation controlled w/ mechanical delay stage 23 cm, ~770ps, or 10.5Lo, Lo=22mm • A new UV stretcher utilizes thick BBO crystals in series • Laser mode at photocathode: adjustable iris at 1 m from photocathode

9. Escalations

10. Principle

13. Monoenergetic Beams from Literature Intensity tL/Tp Energy dE/E Charge Ne [pC] Article Name Lab 3 /cm x10 W/cm ] 18 2 x1018 [MeV] [%] Mangles Nature (04) RAL 73 6 22 20 2,5 1,6 Geddes Nature (04) L'OASIS 86 2 320 19 11 2,2 Faure Nature (04) LOA 170 25 500 6 3 0,7 Hidding PRL (2006) JETI 47 9 0,32 40 50 4,6 Hsieh PRL (2006) IAMS 55 336 40 2,6 Hosokai PRE (2006) U. Tokyo 11,5 10 10 80 22 3,0 Miura APL (2005) AIST 7 20 432E-6 130 5 5,1 Hafz PRE (2006) KERI 4,3 93 200 28 1 33,4 Mori ArXiv (06) JAERI 20 24 0,8 50 0,9 4,5 Mangles PRL (2006) Lund LC 150 20 20 5 1,4 State-of-art gradient 27 GeV/m, SLAC, 27 GeV drive, Nature’2007

14. Towards longer interaction length Diffraction length L~pr2/l0Rayleigh Dephasing length ~ a0 lp3/ l02 Pump depletion length a0 >>1 • Expanding Bubble Injection regime Degrades emittance due to high transverse field – control trapping Pre-formed channel injection : plasma “fiber” Optical injection by colliding pulse Capillary discharge channel

15. 250 mJ, 30 fs ffwhm=30 µm I ~ 4×1017 W/cm2 a1=0.4 700 mJ, 30 fs, ffwhm=16 µm I ~ 3×1018 W/cm2 a0=1.2 LOA Experimental set-up electron spectrometer to shadowgraphy diagnostic Probe beam LANEX Gas jet B Field Pump beam Injection beam

16. LBNL Group

17. - = × 18 3 n 1 . 5 10 cm m l = m 0 . 8 = m m p w 20 0 t = 30 fs f(E) (a.u.) = P 200 TW After 5 Zr / 7.5 mm = a 4 0 2.5 2 1.5 1 0.5 0 800 1200 1600 2000 Energy (MeV) Laser plasma injector : GeV electron beams Courtesy of UCLA& Golp groups

18. Monoenergetic bunch comes from colliding pulses: polarization test Parallel polarization Crossed polarization

19. Is it Easy to Build?

20. Cubic dispersion (gratings etc.) No significance Quadratic dispersion (glass etc.) Spectral Phase

21. Water radiolysis D.A. Oulianov et al JAPS’ (2007).

22. How to control injection? -inject electron beam from LINAC (SLAC, Nature’07) ANL LINAC Chuck Jonah, 1988 21 MeV; 7 ps; 4nC; plasma density 4-7x1010 cm-3 -use laser-based ionization DWA : “chirped” bunches, break down due to CCR multiphoton ionization • *control of laser PW, wavelength • How to control acceleration? -plasma density -channel guiding (LBNL) -colliding pulse (LOA)

25. Acousto-optic shaping Dazzler - from Fastlite No need for zero dispersion stretcher Controls different dispersion orders

26. RGA pulse optimization test w/ SPIDER&Dazzler

27. Injection assisted by laser ionization • Laser-assisted ionization of atoms or ions • Two types: multiphoton and Frank-Keldysh tunneling • 13.6 eV vs 1.5 eV • DFG: Reducing laser frequency increases ponderomotive potential ~w-2 • HE TOPAS ~100 mJ @ l~9 mm

28. Laser techniques • Multi-bunch generation w/ DWA • Pulse shaping • DFG due to detuned from 800 synchronized Regen pulses • Atto-second science: CEP

29. Applications,Conclusions and Perspectives DW should be 7.2 GeV with laser parameters (100TW, a0 ~3, Li~3.8cm) • THz source CCR • Hard X-ray fs source • X-ray free electron lasers • Radiology, biophysics around water window • Early stage of proton acceleration • 1TeV is a goal for HE physics is too far 32 kJ of laser energy (100 lasers of 300J) • Optical Parametric CPA

30. Efficiency • Emittance • Charge • Atto-second -ESASE

31. Thank you

32. Background. Parametric interaction wp = ws + wi phase matching conditions in a uniaxial x-stal such as BBO kp = ks + ki Non-collinear Each photon in idler beam generated together with a photon in signal beam S P I II P

33. PW Spectral Phase Cubic dispersion (gratings etc.) No significance Quadratic dispersion (glass etc.)

34. FROGs • Frequency Resolved Optical Gating (Kane and Trebino’ Opt Lett’ 1993) • Suitable for single-shot detection • Not an interferometric technique, just 2D spectrogram of cross-correlation function • Not easy to reconstruct E(w,t): iterative algorithm, t-direction ambiguity • Slight modification (Masalov et al, JOSA 2001) makes use of spatial interferometry wavelength slit 2nd harmonic Doubling x-stal t

35. Images

36. SPIDER c2 2p/t • Spectral phase interferometry for direct electric-field reconstruction (Iaconis and Walmsley, Opt Lett. ‘ 1998) • Spectral interferogram of two frequency-shifted up-converted pulses; no reference needed • Non-iterative reconstruction algorithm; 1D data set t~2 ps t w

37. APE design

38. Pulse tilt

39. TFPA- pulse front inversion

40. KERI