Les Accélérateurs Laser Plasma

Les Accélérateurs Laser Plasma Victor Malka Laboratoire d Optique Appliquée ENSTA ParisTech Ecole Polytechnique CNRS PALAISEAU, France victor.malka@ensta.fr

Accelerators : One century of exploration of the infinitively small Explored wavelength values (m) 10-11 10-13 10-15 10-17 10-19 10-21 Cathodic tube J. Thomson 1931 E. Lawrence, first Cyclotron @ 80 kev Univ. of Berkeley 380 MeV Cyclotron Berkeley, Bevatron 50 GeV Synchrotron PS 28 GeV CERN 1880 1900 1920 1940 1960 1980 2000 2020 Year SLAC 50 GeV LEP 90 GeV CERN Tevatron FermiLab LHC 3.5 TeV CERN Atom Nucleus Quarks

Industrial Market for Accelerators The development of state of the art accelerators for HEP has lead to : research in other field of science (light source, spallation neutron sources ) industrial accelerators (cancer therapy, ion implant., electron cutting&welding...) Application Total systems (2007) approx. System sold/yr Sales/yr (M$) System price (M$) Cancer Therapy 9100 500 1800 2.0-5.0 Ion Implantation 9500 500 1400 1.5-2.5 Electron cutting and welding 4500 100 150 0.5-2.5 Electron beam and X rays irradiators 2000 75 130 0.2-8.0 Radio-isotope production (incl. PET) 550 50 70 1.0-30 Non destructive testing (incl. Security) 650 100 70 0.3-2.0 Ion beam analysis (incl. AMS) 200 25 30 0.4-1.5 Neutron generators (incl. sealed tubes) 1000 50 30 0.1-3.0 Total 27500 1400 3680 Total accelerators sales increasing more than 10% per year

How to excite relativistic plasma waves? The laser wake field : broad resonance condition τlaser Tp/2 => short laser pulse electron density perturbation and longitudinal wakefield F= I wave in the wake of a boat vphase epw =vg laser c Ez = 0.3 GV/m for 1% density perturbation at 10 17 cm -3 T. Tajima and J. Dawson, PRL 43, 267 (1979) V. Malka et al., PRST-AB 9, 091301 (2006)

Quasi mono-energetic electron beam Electron distribution - Experimental data - 3D PIC Simulations Experimental parameters : E=1J, τl=30fs, λl=0.8μm, ll=3.2 10 18 W/cm 2, ne=6 10 18 cm -3 J. Faure et al., Nature 431, 541 (2004)

Bubble regime : a scientific breakthrough

The Bubble regime : distribution quality improvements SMLWF=>FLWF=>Bubble V. Malka et al., Science 2002,V. Malka et al. Phys. of Plasmas 12, 5 (2005) http://loa.ensta.fr/ UMR 7639

Colliding Laser Pulses Scheme The first laser creates the accelera,ng structure A second laser beam is used to heat electrons Pump beam Injec2on beam Wakefield Ponderomotive force of beatwave: Fp ~ 2a0a1/λ0 (a0 et a1 can be weak ) Boost electrons locally and injects them INJECTION IS LOCAL and IN FIRST BUCKET Theory : E. Esarey et al., PRL 79, 2682 (1997), H. Kotaki et al., PoP 11 (2004) Experiments : J. Faure et al., Nature 444, 737 (2006)

Colliding Laser Pulses Scheme The first laser creates the accelera,ng structure A second laser beam is used to heat electrons Pump beam Injec2on beam Beatwave Wakefield Injec&on phase Ponderomotive force of beatwave: Fp ~ 2a0a1/λ0 (a0 et a1 can be weak ) Boost electrons locally and injects them INJECTION IS LOCAL and IN FIRST BUCKET Theory : E. Esarey et al., PRL 79, 2682 (1997), H. Kotaki et al., PoP 11 (2004) Experiments : J. Faure et al., Nature 444, 737 (2006)

Colliding Laser Pulses Scheme The first laser creates the accelera,ng structure A second laser beam is used to heat electrons Pump beam Trapped electrons Injec2on beam Beatwave Wakefield Accelera&on Injec&on Accelera&on phase phase phase Ponderomotive force of beatwave: Fp ~ 2a0a1/λ0 (a0 et a1 can be weak ) Boost electrons locally and injects them INJECTION IS LOCAL and IN FIRST BUCKET Theory : E. Esarey et al., PRL 79, 2682 (1997), H. Kotaki et al., PoP 11 (2004) Experiments : J. Faure et al., Nature 444, 737 (2006)

Compactness of Laser Plasma Accelerators

Compactness of Laser Plasma Accelerators

Towards a Stable Laser Plasma Accelerators Nb: very few electrons at low energy, δe/e=5% limited by the spectrometer

Towards a Stable Laser Plasma Accelerators Series of 28 consecu,ve shots with : a0=1.5, a1=0.4, ne=5.7 1018cm-3 Nb: very few electrons at low energy, δe/e=5% limited by the spectrometer http://loa.ensta.fr/ UMR 7639

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm late middle early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm Z inj =125 μm late middle early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm Z inj =125 μm Z inj =25 μm late middle early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm Z inj =125 μm Z inj =25 μm late Z inj = 75 μm middle early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm Z inj =125 μm Z inj =25 μm late Z inj = 75 μm Z inj = 175 μm middle early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm Z inj =125 μm Z inj =25 μm late Z inj = 75 μm Z inj = 175 μm Z inj = 275 μm middle early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Tunability of Laser Plasma Accelerators : electrons energy Z inj =225 μm Z inj =125 μm Z inj =25 μm late Z inj = 75 μm Z inj = 175 μm Z inj = 275 μm middle Z inj = 375 μm early injec+on accelerating distance J. Faure et al., Nature 444, 737 (2006)

Mono energetic distribution : 1% relative energy spread C. Rechatin et al., Phys. Rev. Lett. 102, 194804 (2009)

1.5 fs RMS duration : Peak current of 4 ka Analytic CTR model Gaussian pulse shape Measured e-beam : Charge Energy Divergence Bunch duration Peak wavelength Peak intensity Spectral features Peak at 3 μm Coherent 1.5 fs RMS duration : Peak current of 4 ka O. Lundh et al., Nature Physics, March 2011

1.5 fs RMS duration : Peak current of 4 ka Analytic CTR model Gaussian pulse shape Measured e-beam : Charge Energy Divergence Bunch duration Peak wavelength Peak intensity Spectral features Peak at 3 μm Coherent 1.5 fs RMS duration : Peak current of 4 ka O. Lundh et al., Nature Physics, March 2011

Cancer treatment improvements : real case of prostate sagittal view irradiation at 7 angles Transversal view 250 MeV electrons X rays IMRT Difference Laser-accelerated electrons can provide a better dose sparing of critical structures (up to 19%) at a similar target coverage compared to photons. Y. Glinec, et al., Med. Phys. 33, (1) 155-162 (2006) T. Fuchs, et al. Phys. Med. Biol. 54, 3315-3328 (2009)

Applications for material science : γ radiography 400 μm γ source size 2005 50 μm γ source size 2010 Y. Glinec et al., PRL 94, 025003 (2005) A. Ben-Ismail et al., APL 2011 http://loa.ensta.fr/ UMR 7639

Conclusions Good beam quality & Monoenergetic de/e down to 1 % Beam is very stable Energy is tunable: 20-300 MeV Charge is tunable: 1 to tens of pc Energy spread is tunable: 1 to 10 % Ultra short e-bunch : 1,5 fs rms Ultra high current e-bunch : 3-4 ka Results extremely important for : Designing future accelerators Light source development for XFEL and for applications (chemistry, radiotherapy, material science) V. Malka et al., Nature Physics 4, June 2008

Laser Plasma Accelerator : a Wonderful Tool for Science and for Academic Activities T T T T T T.. TT. T TTT Ṭ. T T T T...... T T T. ELI-NP

Acknowledgements A. Ben Ismail, S. Corde, J. Faure, S. Fritzler, Y. Glinec, A. Lifshitz, J. Lim, O. Lundh, C. Rechatin, Kim Ta Phuoc, and C. Thaury from LOA E. Lefebvre and X. Davoine from CEA/DAM CARE/FP6-Euroleap/FP6-Accel1/ANR-PARIS/ERC contracts