260 likes | 431 Views
LOA. Strategies for Future Laser Plasma Accelerators. V.Malka, J. Faure, Y. Glinec , A. Lifschitz, C. Réchatin Laboratoire d’Optique Appliqu é e ENSTA-Ecole Polytechnique , CNRS 91761 Palaiseau, FRANCE. Partially supported by CARE/PHIN FP6 project.
E N D
LOA Strategies for Future Laser Plasma Accelerators V.Malka, J. Faure, Y. Glinec, A. Lifschitz, C. Réchatin Laboratoire d’Optique Appliquée ENSTA-Ecole Polytechnique, CNRS 91761 Palaiseau, FRANCE Partially supported by CARE/PHIN FP6 project CARE annual meeting, CERN October 29-31 (2007)
LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2 : Laser plasma accelerator as booster Part 3 : Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 4 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 5 : Conclusion and perspectives CARE annual meeting, CERN October 29-31 (2007)
100 mm Plasma cavity Classical accelerator limitations E-field max ≈ few 10 MeV /meter (Breakdown) R>Rmin Synchrotron radiation Courtesy of W. Mori & L. da Silva 1 m RF cavity LOA CARE annual meeting, CERN October 29-31 (2007)
LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2 : Laser plasma accelerator as booster Part 3: Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 4 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 5 : Conclusion and perspectives CARE annual meeting, CERN October 29-31 (2007)
Accelerating Ez Decelerating Defocusing Er Focusing LOA Accelerating & focusing fields in Linear RPW Small Laser amplitude a0=0.5 Homogeneous plasma Pulse Electron density CARE annual meeting, CERN October 29-31 (2007)
LOA Accelerating & focusing fields in plasma channel Small Laser amplitude a0=0.5 Parabolic plasma channel Pulse Electron density Pulse Accelerating Ez Decelerating Defocusing Er Focusing CARE annual meeting, CERN October 29-31 (2007)
Accelerating Decelerating Defocusing Focusing LOA Accelerating & focusing fields in NL RPW Large Laser amplitude a0=2 Homogeneous plasma relativistic shift of wp Pulse Electron density CARE annual meeting, CERN October 29-31 (2007)
LOA Three Injection schemes High Energy => Short Bunch Before the pulse Low energy => Low charge Low energy laser CARE annual meeting, CERN October 29-31 (2007)
LOA Electric field Electron bunch GeV’s acceleration in two-stages Laser Gas-Jet Laser Plasma channel GeV • 1 J • 10 TW • 30 fs • 50-150 TW • ~50 fs Nozzle • 170±20 MeV • 30 fs • 10 mrad Density profile rc • Pulse guiding condition : Δn>1/πre rc2 Δn • Weak nonlinear effects more control : a0 ~ 1-2 • High quality beams : Lb <λp n0<1018 cm-3 n0 Short bunch Ultra-short bunch Electric field Electron bunch CARE annual meeting, CERN October 29-31 (2007)
LOA tbunch = 200 fs CARE annual meeting, CERN October 29-31 (2007)
LOA Injecting the LOA e-beam @ tbunch = 30 fs, 170 MeV CARE annual meeting, CERN October 29-31 (2007)
LOA 3 GeV, 1% energy spread e-beam • E=9 J • P= 0.15 PW • a0=1.5 • Parabolic channel: • r0=47 m, • n(r)=n0 (1+0.585 r/r0) • n0 = 1.1×1017 cm-3 3.4 GeV, with a relative energy spread FWHM of 1% and an unnormalized emittance of 6 mm. CARE annual meeting, CERN October 29-31 (2007)
LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2 : Laser plasma accelerator as booster Part 3: Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 4 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 5 : Conclusion and perspectives CARE annual meeting, CERN October 29-31 (2007)
LOA Laser plasma injector Scheme of principle Experimental set up CARE annual meeting, CERN October 29-31 (2007)
Divergence = 6 mrad LOA Energy distribution improvements: The Bubble regime Charge in the peak : 200-300 pC Experiment PIC At LOA J. Faure et al. Nature (2004) CARE annual meeting, CERN October 29-31 (2007)
Quasi-monoenergetic beamsreported in the litterature Intensity tL/Tp Remark Energy dE/E Charge Ne Article Name Lab /cm ] [x10 W/cm ] 18 2 [pC] [x1018 3 [MeV] [%] Mangles Nature (2004) RAL 73 6 22 20 2,5 1,6 Geddes Nature (2004) L'OASIS 86 2 320 19 11 2,2 Channel Faure Nature (2004) 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 Preplasma 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 (2006) JAERI 20 24 0,8 50 0,9 4,5 Mangles PRL (2006) Lund LC 150 20 20 5 1,4 Several groups have obtained quasi monoenergetic e beam but at higher density (tL>tp) LOA CARE annual meeting, CERN October 29-31 (2007)
LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2 : Laser plasma accelerator as booster Part 3: Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 4 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 5 : Conclusion and perspectives CARE annual meeting, CERN October 29-31 (2007)
electrons Principle: Pump beam Injection beam Plasma wave LOA Controlling the injection pump injection Counter-propagating geometry: Ponderomotive force of beatwave: Fp ~ 2a0a1/λ0 (a0 et a1 can be “weak”)y Boost electrons locally and injects them:y INJECTION IS LOCAL IN FIRST BUCKETy E. Esarey et al, PRL 79, 2682 (1997), G. Fubiani et al. (PRE 2004) CARE annual meeting, CERN October 29-31 (2007)
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 Experimental set-up to shadowgraphy diagnostic electron spectrometer Probe beam LANEX Gas jet B Field Injection beam Pump beam
LOA CARE annual meeting, CERN October 29-31 (2007)
Improvement of the stability 2D images IFSA, Kobe, Japan September 9-15 (2007)
STATISTICS value and standard deviation Bunch charge= 19pC, s = 6.8 pC Peak energy= 117MeV, s=7 MeV DE= 13MeV, s = 2.5 MeV DE/E= 11 %, s = 2 % Divergence= 5.7 mrad Pointing stability= 1.8 mrad LOA Optical injection by colliding pulses leads to stable monoenergetic beams CARE annual meeting, CERN October 29-31 (2007)
injection pump Zinj=225 μm Zinj=125 μm late injection Zinj=25 μm injection pump Zinj=-75 μm Zinj=-175 μm middle injection Zinj=-275 μm injection pump Zinj=-375 μm early injection LOA Tunable monoenergetic bunches J. Faure et al., Nature, 2006 CARE annual meeting, CERN October 29-31 (2007)
LOA Tunable monoenergetic electrons bunches: 190 MeV gain in 700 µm: E=270 GV/m Compare with Emax=mcwp/e=250 GV/m at ne=7.5×1018 cm-3 CARE annual meeting, CERN October 29-31 (2007)
LOA Conclusions / perspectives SUMMARY • Optical injection by colliding pulse: it works ! • Monoenergetic beams trapped in first bucket • Enhances dramatically stability • Energy is tunable: 15-300 MeV • Charge up to 80 pC in monoenergetic bunch • dE/E down to 5 % (spectrometer resolution), dE ~ 10-20 MeV • Duration shorter than 10 fs. PERSPECTIVES Q • Combine with waveguide: tunable up to few GeV’s with dE/E ~ 1 % • Design future accelerators • Model the problem for further optimization: higher charge • Stable source: extremely important • accelerator development (laser based accelerator design) • light source development for XFEL • applications (chemistry, radiotherapy, material science) CARE annual meeting, CERN October 29-31 (2007)