Journées accélérateurs, Roscoff, FRANCE , 9-12 (2005)

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Journées accélérateurs, Roscoff, FRANCE , 9-12 (2005)

Laser-plasma accelerators:

Status and perspectives

Victor Malka

LOA, ENSTA – CNRS - École Polytechnique,91761 Palaiseau cedex, France

Journées accélérateurs, SFP, Roscoff 05 FRANCE 1/38

170 +/-20MeV500 pC6 mrad

Gas jet

laser

Electron beam

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CARE / FP6

Particle group

F. EwaldJ. FaureY. GlinecA. LifschitzJ.J. Santos

Laser group

F. BurgyB. MercierJ.Ph. Rousseau

A. Pukhov, University of Dusseldorf, Germany

ELFSPL

Collaborators

E. Lefebvre, CEA/DAM Ile-de-France, FranceP. Mora, CPhT, X, CNRS, France


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E-field max ≈ few 10 MeV /meter (Breakdown) R>Rmin Synchrotron radiation

Classical accelerator limitations

LEP at CERN

27 km

Circle road

31 km

New medium : the plasma

Energy = Length = $$$

≈ PARIS


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Why is a Plasma useful ?

• Plasma is an Ionized Medium High Electric Fields

epz nE ~~w

• Superconducting RF-Cavities : Ez = 55 MV/m

eznE ~

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


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Tajima&Dawson, PRL79

How to excite Relativistic Plasma waves?

The laser wake field

laser≈ Tp / 2=>Short laser pulse

Laser pulse

F≈-grad I

Electron density perturbation

Phase velocity vepw=vglaser => close to c

Analogy with a boat


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FF≈-grad I

Train of short resonant pulsesLaser envelop modulation

k

k2

How to excite Relativistic Plasma waves?(ii) The laser beat waves

$$$$! 1-2 = p

Linear growth : d(t)=1/4a1a2wpt

=>Homogenous plasmasSaturation : relativistic,

ion motion

Optical demonstration by Thomson scattering :

Clayton et al. PRL 1985,Amiranoff et al. PRL 1992,, Dangor et al. Phys. Scrypta 1990

Chen, Introduction to plasma physics and controlled fusion, 2nd Edition, Vol.1, (1984)

Motivations


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electron

Analogy:

t1 t2 t3

e >> >> 1

=> Emax(MeV)=( n/n)(nc/ne)

=>Ldeph.=(0/2)(nc /n e)3/2

Emax=2(n/n) 2mc2

L Deph. =p2

Analogy electron/surfer Motivations


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Motivations


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Few MeV gain

Laser

Injected electronsFew MeV

Injected electrons acceleration with laser :

Wake field , Beat wave

Motivations


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Electron Acceleration : LBWFElectron spectra indicate an Efield of ≈ 0.7 GV/m

= 100 , e = 6 , laser = 40 µm , e = 40 µm , divergence = 10 mrad

Ele

ctr

on

s

nu

mb

er

exp

eri

men

t

0

100

200

300

400

500

600

0

500

1000

1500

2000

3,3 3,4 3,5 3,6 3,7 3,8 3,9

Th

eory

Energy (MeV)

d = 1,6%

LULI/LPNHE/LPGP/LSI/IC

Electron gain demonstration Few MeV’s:Kitagawa et al. PRL 1992,Clayton et al. PRL 1993,N. A. Ebrahim et al.,

J. Appl. Phys.1994, Amiranoff et al. PRL 1995

Motivations


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How to generate an electron beam?Self-modulated Laser Wakefield Scheme

(Andreev et al., Sprangle et al., Antonsen & Mora 1992)

cp

enhances

WavebreakingPc(GW) = 17 02/p

2

Short Pulse Energetic Electronsif then

excites

Modena et al., Nature 1995Journées accélérateurs, SFP, Roscoff 05 FRANCE 11/38

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Wave breaking : from waves to particles


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5-pass Amp. : 200 mJ

8-pass pre-Amp. : 2 mJ

Oscillator : 2 nJ, 15 fs

Stretcher : 500 pJ, 400 ps

After Compression :1 J, 30 fs, 0.8 m,

10 Hz, 10 -7

2 m

Nd:YAG : 10 J

4-pass, Cryo. cooled Amp. :< 3.5 J, 400 ps

Salle Jaune Laser based on CPA

technique


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z

rayon2 mill.

2 mill.

z

rayon2 mill.

2 mill.

10

5

0

Phase

(ra

dia

ns)

16

5

1Densi

ty (

101

8 c

m-3

)

0

2 1018

4 1018

6 1018

8 1018

1 1019

-4 -3 -2 -1 0 1 2 3 4

Rayon (mm)

Densi

té d

e n

eutr

e (

cm-3

)

The target gas jetDeveloped at the gas jet’s lab

V. Malka et al., RSI (2000)Journées accélérateurs, SFP, Roscoff 05 FRANCE 14/38

L O AS. Semushin & V. Malka , RSI (2001)

Gas Jet Nozzle Design and improvementFor laser plasma studies

D critmm

D exitmm

L optmm

Machexit

N ext cm-3

1 2 6 3.5 18 x 1019

1 3 7 4.75 7.5 x 1019

1 5 10 7 2.7 x 1019

1 10 15 10 0.75 x 1019

0.5 1 4 3.3 16 x 1019

0.5 2 5 5.5 4.5 x 1019

0.5 3 5 6.2 2.1 x 1019

0.5 5 7 9.5 0.7 x 1019

D critmm

D exitmm

L optmm

Machexit

N ext cm-3


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10

100

1019 1020E

max (

MeV

)n

e (cm -3)

Emax=4p2mec

2dnn

Tunable electron beam : temperature

Electrons are accelerated by epw

V. Malka et al., PoP (2001)

F/6

106

107

108

109

1010

0 10 20 30 40 50 60 70

# e

lect

rons/

MeV

/sr

W (MeV)

Teff=8.1 MeV

Teff=2.6MeV

detection threshold

Ne=1.5x1019cm-3

Ne=1.5x1020cm-3

INCREASE THE ACCELERATION LENGTH


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Interaction chamber (inside)

Laser beam

electron beam

50 cm


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Summary of FLWF previous results

Experiments/3D PIC simulations

V. Malka et al., Science, 298, 1596 (2002)

105

106

107

108

109

1010

0 50 100 150 200Energy (MeV)

Detection Threshold

Num

ber

of

ele

ctro

n (

/MeV

/sr)

Emittance is indeed comparable with todays Accelerators

Electron Energy (MeV)

n (

mm

mra

d)

20 40 60

20

40

Ee- = ~ 55 MeV = ~ 3 mm mradn

S. Fritzler et al., PRL 04Journées accélérateurs, SFP, Roscoff 05 FRANCE 18/38

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SMLWF : Multiple e- bunches / FLWF Single e- bunch

V. Malka, Europhysics news, April 2004 (Ps/fs)

Electron bunches

laser

Electric field

Ps

Electron bunch

laserElectron density perturbation

ne/n0-1

Electric field

0

fs


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700

650

Z/

20

-20

Y/

-20

2 0

X/

Quasi-Monoenergetic Electron Beams

In homogenous plasma : virtual or real?

0 200 400 E, MeV

t=350

t=450

t=550

t=650

t=750

t=850

5 108

1 109Ne / MeV

Time evolution of electron spectrum

monoenergeticelectron beam

VLPL

A.Pukhov & J.Meyer-ter-Vehn, Appl. Phys. B, 74, p.355 (2002)

One stage LPA


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Experimental Setup : single shot measurement


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2.0 x 1019cm-3

Divergence = 6 mrad

Spatial quality improvements

6.0 x 1018cm-37.5 x 1018cm-31.0 x 1019cm-3

5.0 x 1019cm-3 3.0 x 1019cm-3


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From Mono to maxwellian spectra : the bubble regime : optimum when cL p

V. Malka, et al., PoP 2005


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Charge in [150-190] MeV : (500 ±200) pC

Energy distribution improvements:The Bubble regime

PIC

Experiment

Divergence = 6 mrad

J. Faure et al.,

in Nature 30 septembre 2004Journées accélérateurs, SFP, Roscoff 05 FRANCE 24/38

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Some Applications ...

X-rays:diffractionmedicine

-rays:radiography

MedicineRadiotherapy Proton-therapy

PET

Accelerator Physics

Chemistry

Radiolysis

Electrons and Protonsgenerated byLaser-PlasmaInteractions

+X ray LarmorX ray laser


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GeV acceleration in two-stages

GeV

Laser Plasma channel

•50-150 TW•~50 fs

Nozzle

Gas-JetLaser

•170±20 MeV•30 fs•10 mrad

•1 J•10 TW•30 fs

•Pulse guiding condition : Δn>1/πre rc2

•Weak nonlinear effects more control : a0 ~ 1-2

•High quality beams : Lb <λp n0<1018 cm-3

rc

Δnn0

Density profile


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GeV in low plasma density in plasma channel

V. Malka et al., to be published in Royal Society and Phil. Trans.

GeV in low plasma density in plasma channel

n0=8 1016 cm-3, 11 J - 140 TW rc=40 μm, Δn=2 n0

L channel=4 cm 8 cm

12 cm

4

2

3

1

00 800400 1200

dN

/dE

(a.u

.)

Energy (MeV)Electron bunch

Electric field

Electron bunch

Electric field


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On the ultra short duration benefitfs 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.


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In collaboration with L. Le-Dain, S. Darbon from CEA Mourainvilier and DAM

Material science: -ray radiography

High resolution radiography of dense object with a low divergence, point-like electron source

Glinec et al., PRL 94 p025003 (2005)Journées accélérateurs, SFP, Roscoff 05 FRANCE 29/38

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-radiography results

A-A' cut

20mm

Cut of the object in 3D

• Spherical hollow object in

tungsten with sinusoidal

structures etched on the

inner part.

Measured Calculated

Source size estimation : 450 um


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Medical application : Radiotherapy

VHE ELECTRONS


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Radiation Therapy

Depth in tissue

Photon dose

Photon beams are commonly used for radiation therapy

tumor

tumor

Photon beam


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VHE Radiation Therapy

Depth in tissue

VHE dose

Reduced dose in save cellsDeep traitementGood lateral contrast

tumor

tumor

VHE


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Dose deposition profile in water

Glinec et al., Accepted to Med. Phys.In collaboration with DKFZ (Germany)Journées accélérateurs, SFP, Roscoff 05 FRANCE 34/38

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Laser plasma acceleration has demonstrated•Energy gains of 1 MeV to 200 MeV•E-fields of 1 GV/m to 1000 GV/m•Good e-beam quality : Emittance < 3mm.mrad

•charge at high energy•Quasi monoenergetic

Laser plasma accelerators advantages Provide e-beam with new parameters : shortProvide e-beam with new parameters : high currentProvide e-beam with new parameters : CollimatedCompact and low cost

The laser plasma accelerators status

ゝゝ

ゝゝ

ゝゝ

ゝゝ

ゝ


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Laser plasma accelerator:

• enhance stability•electron sources up to ≈ 1 GeV (nC, <1 ps): Guiding or PW class laser systems Single Stage (Pukhov, Mori) (200TW)

•Generate a tunable e-beam• applications of these electron sources •Compact XFEL

Perspectives


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Next Step: GeV electron beams (1 stage)

LT 1.0cm

Ldp 1.3cm

E 1.5GeV

After 5 Zr / 7.5 mm

Total charge = 1.1 nC

0

0.5

1

1.5

2

2.5

800 1200 1600 2000Energy (MeV)

f(E) (a.u.)

w020 m 30 fs a0

40.8mP 200TW np 1.5 1018 cm3

P

Pc10

* Gordienko et al, PoP 2005, UCLA group


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A revolution is coming…one of the most evolving field in Science, a wonderful tool for academic formation

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Thanks for your attention !

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Journées accélérateurs, Roscoff, FRANCE , 9-12 (2005)

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