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Laser-plasma accelerators: Status and perspectives. Victor Malka LOA, ENSTA – CNRS - École Polytechnique, 91761 Palaiseau cedex, France. laser. Electron beam. 170 +/-20MeV 500 pC 6 mrad. Gas jet. Journées accélérateurs, Roscoff, FRANCE , 9-12 (2005). - PowerPoint PPT Presentation
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L O A
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
L O A
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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 2/38
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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 = $$$
≈ PARIS
Journées accélérateurs, SFP, Roscoff 05 FRANCE 3/38
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Why is a Plasma useful ?
• Plasma is an Ionized Medium High Electric Fields
epz nE ~~w
• Superconducting RF-Cavities : Ez = 55 MV/m
eznE ~
Are Relativistic Plasma waves efficient ?
Ez = 0.3 GV/m for 1 % Density Perturbation at 1017 cc-1
Ez = 300 GV/m for 100 % Density Perturbation at 1019 cc-1
Journées accélérateurs, SFP, Roscoff 05 FRANCE 4/38
L O A
Tajima&Dawson, PRL79
How to excite Relativistic Plasma waves?
The laser wake field
laser≈ Tp / 2=>Short laser pulse
Laser pulse
F≈-grad I
Electron density perturbation
Phase velocity vepw=vglaser => close to c
Analogy with a boat
Journées accélérateurs, SFP, Roscoff 05 FRANCE 5/38
L O A
FF≈-grad I
Train of short resonant pulsesLaser envelop modulation
k
k2
How to excite Relativistic Plasma waves?(ii) The laser beat waves
$$$$! 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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 6/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 7/38
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Motivations
Journées accélérateurs, SFP, Roscoff 05 FRANCE 8/38
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Few MeV gain
Laser
Injected electronsFew MeV
Injected electrons acceleration with laser :
Wake field , Beat wave
Motivations
Journées accélérateurs, SFP, Roscoff 05 FRANCE 9/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 10/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 12/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 13/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 15/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 16/38
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Interaction chamber (inside)
Laser beam
electron beam
50 cm
Journées accélérateurs, SFP, Roscoff 05 FRANCE 17/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 19/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 20/38
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Experimental Setup : single shot measurement
Journées accélérateurs, SFP, Roscoff 05 FRANCE 21/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 22/38
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From Mono to maxwellian spectra : the bubble regime : optimum when cL p
V. Malka, et al., PoP 2005
Journées accélérateurs, SFP, Roscoff 05 FRANCE 23/38
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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
L O A
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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 25/38
L O A
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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 26/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 27/38
L O A
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.
Journées accélérateurs, SFP, Roscoff 05 FRANCE 28/38
L O A
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
L O A
-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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 30/38
L O A
Medical application : Radiotherapy
VHE ELECTRONS
Journées accélérateurs, SFP, Roscoff 05 FRANCE 31/38
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Radiation Therapy
Depth in tissue
Photon dose
Photon beams are commonly used for radiation therapy
tumor
tumor
Photon beam
Journées accélérateurs, SFP, Roscoff 05 FRANCE 32/38
L O A
VHE Radiation Therapy
Depth in tissue
VHE dose
Reduced dose in save cellsDeep traitementGood lateral contrast
tumor
tumor
VHE
Journées accélérateurs, SFP, Roscoff 05 FRANCE 33/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 35/38
L O A
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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 36/38
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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
Journées accélérateurs, SFP, Roscoff 05 FRANCE 37/38
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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, SFP, Roscoff 05 FRANCE 38/38
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