Laser Plasma Accelerators: Principle & applications LOA Laser Plasma Accelerators: Principle & applications Victor Malka Laboratoire d’Optique Appliquée ENSTA-Ecole Polytechnique, CNRS 91761 Palaiseau, FRANCE Partially supported by CARE/PHIN FP6 project John Adams Insitute, Oxford UK, January 10, 2008

Acknowledgement SPL ELF Particle group Laser group J. Faure F. Burgy LOA Acknowledgement SPL ELF Particle group J. Faure Y. Glinec A. Lifschitz C. Rechatin Laser group F. Burgy B. Mercier J.Ph. Rousseau Collaborators Pukhov, University of Dusseldorf, Germany E. Lefebvre, CEA/DAM Ile-de-France, France John Adams Insitute, Oxford UK, January 10, 2008

Summary Part 1 : Laser plasma accelerator : motivation LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2 : Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 3 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 4 : Applications Part 5 :Conclusion and perspectives John Adams Insitute, Oxford UK, January 10, 2008

Classical accelerator limitations LOA Classical accelerator limitations E-field max ≈ few 10 MeV /meter (Breakdown) R>Rmin Synchrotron radiation Energy = Length = $$$ Circle road LEP at CERN PARIS ≈ 27 km 31 km New medium : the plasma John Adams Insitute, Oxford UK, January 10, 2008

n E ~ w Why is a Plasma useful ? LOA Why is a Plasma useful ? Superconducting RF-Cavities : Ez = 55 MV/m Plasma is an Ionized Medium High Electric Fields e p z n E ~ w John Adams Insitute, Oxford UK, January 10, 2008

n E ~ How to excite Relativistic Plasma waves? The laser wake field LOA How to excite Relativistic Plasma waves? The laser wake field Laser pulse F≈-grad I Electron density perturbation Phase velocity vfepw=vglaser => close to c Analogy with a boat tlaser≈ Tp / 2 =>Short laser pulse e z n E ~ Are Relativistic Plasma waves efficient ? Ez = 0.3 GV/m for 1 % Density Perturbation at 1017 cc-1 Ez = 300 GV/m for 100 % Density Perturbation at 1019 cc-1 Tajima and Dawson, PRL (1979) Tajima&Dawson, PRL79 John Adams Insitute, Oxford UK, January 10, 2008

Analogy electron/surfer LOA Analogy electron/surfer t 1 t t 2 3 électron g > > g f > > 1 e => E max (MeV)­( d n/n)(n c /n e ) =>L deph. =( l /2)(n 3/2 E =2( n/n) g f 2 mc L Deph. = p Analogy: John Adams Insitute, Oxford UK, January 10, 2008

LOA John Adams Insitute, Oxford UK, January 10, 2008

Classical accelerator limitations Courtesy of W. Mori & L. da Silva Plasma cavity 100 mm 1 m RF cavity LOA John Adams Insitute, Oxford UK, January 10, 2008

Summary Part 1 : Laser plasma accelerator : motivation LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2: Laser Plasma accelerator as injector : Production of electron beam Part 3 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 4 : Applications Part 5 :Conclusion and perspectives John Adams Insitute, Oxford UK, January 10, 2008

Interaction chamber (inside) LOA Interaction chamber (inside) Laser beam electron beam 50 cm John Adams Insitute, Oxford UK, January 10, 2008

Laser plasma injector Scheme of principle Experimental set up LOA John Adams Insitute, Oxford UK, January 10, 2008

Spatial quality improvements LOA Spatial quality improvements 5.0 x 1019cm-3 3.0 x 1019cm-3 2.0 x 1019cm-3 1.0 x 1019cm-3 7.5 x 1018cm-3 6.0 x 1018cm-3 Divergence = 6 mrad John Adams Insitute, Oxford UK, January 10, 2008

Recent results on e-beam : From Mono to maxwellian spectra LOA Recent results on e-beam : From Mono to maxwellian spectra Electron density scan V. Malka, et al., PoP 2005 John Adams Insitute, Oxford UK, January 10, 2008

Energy distribution improvements: LOA Energy distribution improvements: The Bubble regime Charge in the peak : 200-300 pC Divergence = 6 mrad Experiment PIC At LOA J. Faure et al. Nature (2004) John Adams Insitute, Oxford UK, January 10, 2008

Other results RAL & LBNL also to be published tomorrow in Nature 04 LOA Other results RAL & LBNL also to be published tomorrow in Nature 04 50 pC 300 pC RAL & LBNL John Adams Insitute, Oxford UK, January 10, 2008

S. Mangles et al., C. Geddes et al., J. Faure et al., LOA S. Mangles et al., C. Geddes et al., J. Faure et al., in Nature 30 septembre 2004 John Adams Insitute, Oxford UK, January 10, 2008

Quasi-monoenergetic beams reported in the litterature Article Energy dE/E Charge Ne Intensity tL/Tp Remark Name Lab [MeV] [%] [pC] [x1018 /cm 3 ] [x10 18 W/cm 2 ] 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 John Adams Insitute, Oxford UK, January 10, 2008

GeV electron beams from a « centimetre-scale » accelerator 310-μm-diameter channel capillary P = 40 TW density 4.3×1018 cm−3. Leemans et al., Nature Physics, september 2006 LOA John Adams Insitute, Oxford UK, January 10, 2008

Summary Part 1 : Laser plasma accelerator : motivation LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2: Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 3 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 4 : Applications Part 5 :Conclusion and perspectives John Adams Insitute, Oxford UK, January 10, 2008

Controlling the injection LOA Controlling the injection pump injection Counter-propagating geometry: Plasma wave Principle: Pump beam electrons Injection beam 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 BUCKET y E. Esarey et al, PRL 79, 2682 (1997), G. Fubiani et al. (PRE 2004) John Adams Insitute, Oxford UK, January 10, 2008

Experimental set-up to shadowgraphy diagnostic electron spectrometer LOA Experimental set-up to shadowgraphy diagnostic electron spectrometer Probe beam LANEX Gas jet B Field Injection beam Pump beam 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 John Adams Insitute, Oxford UK, January 10, 2008

LOA John Adams Insitute, Oxford UK, January 10, 2008

From self-injection to external injection LOA From self-injection to external injection pump Single beam ne=1.25×1019 cm-3 ne=1019 cm-3 Self-injection Threshold ne=7.5×1018 cm-3 pump injection 2 beams ne=7.5×1018 cm-3 John Adams Insitute, Oxford UK, January 10, 2008

Optical injection by colliding pulses LOA Optical injection by colliding pulses leads to stable monoenergetic beams STATISTICS value and standard deviation Bunch charge= 19 +/- 6 pC Peak energy= 117 +/- 7 MeV DE= 13 +/- 2.5 MeV DE/E= 11 % +/- 2 % Divergence= 5.7 +/- 2 mrad Pointing stability= 2 mrad *Charge measurements with absolute calibration of Lanex film (ICT gave a factor of 8 higher charge) John Adams Insitute, Oxford UK, January 10, 2008

Monoenergetic bunch comes from colliding pulses: polarization test LOA Monoenergetic bunch comes from colliding pulses: polarization test Parallel polarization Crossed polarization John Adams Insitute, Oxford UK, January 10, 2008

Controlling the bunch energy by controlling the acceleration length LOA By changing delay between pulses: Change collision point Change effective acceleration length Tune bunch energy Pump beam Injection beam 2 mm Gas jet John Adams Insitute, Oxford UK, January 10, 2008

Tunable monoenergetic bunches LOA Tunable monoenergetic bunches pump injection late injection early injection middle injection Zinj=225 μm Zinj=125 μm Zinj=25 μm Zinj=-75 μm Zinj=-175 μm Zinj=-275 μm Zinj=-375 μm J. Faure et al., Nature 2006 John Adams Insitute, Oxford UK, January 10, 2008

Tunable monoenergetic electrons bunches: 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 John Adams Insitute, Oxford UK, January 10, 2008

Summary Part 1 : Laser plasma accelerator : motivation LOA Summary Part 1 : Laser plasma accelerator : motivation Part 2 : Laser Plasma accelerator as injector : Production of monoenergetic electron beam Part 3 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam. Part 4 : Applications Part 5 :Conclusion and perspectives John Adams Insitute, Oxford UK, January 10, 2008

GeV acceleration in two-stages LOA GeV acceleration in two-stages Gas-Jet Laser Laser Plasma channel GeV 1 J 10 TW 30 fs Nozzle 50-150 TW ~50 fs 170±20 MeV 30 fs 10 mrad Density profile rc Δn Pulse guiding condition : Δn>1/πre rc2 n0 Weak nonlinear effects  more control : a0 ~ 1-2 High quality beams : Lb <λp  n0<1018 cm-3 John Adams Insitute, Oxford UK, January 10, 2008

GeV in low plasma density in plasma channel LOA GeV in low plasma density in plasma channel n0=8 1016 cm-3, 11 J - 140 TW rc=40 μm, Δn=2 n0 Electric field 4 L channel=4 cm 8 cm 12 cm Electron bunch 3 dN/dE(a.u.) 2 Electric field 1 400 800 1200 Energy (MeV) Electron bunch V. Malka et al., Plasma Phys. Control. Fusion 47 (2005) B481–B490 John Adams Insitute, Oxford UK, January 10, 2008

Injecting the LOA e-beam @ tbunch = 30 fs, 170 MeV John Adams Insitute, Oxford UK, January 10, 2008

3 GeV, 1% energy spread e-beam 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 3.5 GeV, with a relative energy spread FWHM of 1% and an unnormalized emittance of 0.006 mm. V. Malka et al., PRSTA 9, 091301 2006 John Adams Insitute, Oxford UK, January 10, 2008

Material science: g-ray radiography LOA Material science: g-ray radiography High resolution radiography of dense object with a low divergence, point-like electron source In collaboration with CEA / DAM Glinec et al., PRL 94 025003 (2005) John Adams Insitute, Oxford UK, January 10, 2008

g-radiography results 20mm Measured Calculated Cut of the object in 3D Spherical hollow object in tungsten with sinusoidal structures etched on the inner part. Source size estimation : 450 um Glinec et al., PRL 94 025003 (2005) LOA John Adams Insitute, Oxford UK, January 10, 2008

Particle beam in medicine : Radiotherapy 99% Radiotherapy with X ray LOA John Adams Insitute, Oxford UK, January 10, 2008

Radiation Therapy : context Photon beams are commonly used for radiation therapy Photon dose Photon beam Dose tumor tumor Depth in tissue LOA John Adams Insitute, Oxford UK, January 10, 2008

Medical application : Radiotherapy VHE ELECTRONS LOA John Adams Insitute, Oxford UK, January 10, 2008

VHE Radiation Therapy Reduced dose in save cells Deep traitement Good lateral contrast VHE Dose VHE dose tumor tumor Depth in tissue LOA John Adams Insitute, Oxford UK, January 10, 2008

Clinically approved prostate treatment with seven fields irradiation LOA Clinically approved prostate treatment with seven fields irradiation Transversal view Sagittal view John Adams Insitute, Oxford UK, January 10, 2008

Improved treatment with electrons LOA Improved treatment with electrons A typical transversal dose distribution with 7 beams. Electrons Photons Difference A comparison of dose deposition with 6 MeV X ray an improvement of the quality of a clinically approved prostate treatment plan. While the target coverage is the same or even slightly better for 250 MeV electrons compared to photons the dose sparing of sensitive structures is improved (up to 19%). T. Fuchs, DKFZ in preparation John Adams Insitute, Oxford UK, January 10, 2008

Fudamental aspect : fs radiolysis H2O (e-s, OH., H2O2, H3O+, H2, H.) e- Very important for: Biology Ionising radiations effects B. Brozek-Pluska et al., Radiation and Chemistry, 72, 149-159 (2005) **Ar. LOA John Adams Insitute, Oxford UK, January 10, 2008

Compact XFEL: towards a bright X ray source Reduction of accelerator Reduction of the undulator q ~ mrad 10cm Applications: study of complex structures (X-ray diffraction, EXAFS) But ps time scale LOA John Adams Insitute, Oxford UK, January 10, 2008

Parameter designs Laser Plasma Accelerators LOA Parameter designs Laser Plasma Accelerators ELI : > 100 GeV a0=4 P(PW) τ (fs) ne(cm-3) W0 (μm) L(m) E(J) Q(nC) E(Gev) 0.12 30 2e18 15 0.009 3.6 1.3 1.12 1.2 100 2e17 47 0.28 120 4 11.2 12 300 2e16 150 9 3.6k 13 112 120 1000 2e15 470 280 120k 40 1120 Golp and UCLA Group John Adams Insitute, Oxford UK, January 10, 2008

Conclusions / perspectives 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) John Adams Insitute, Oxford UK, January 10, 2008