1. Stable and Tuneable Laser Plasma Accelerators
J. Faure, Y. Glinec, A. Lifschitz,
A. Norlin, C. Réchatin, V.Malka
Laboratoire d’Optique Appliquée
ENSTA-Ecole Polytechnique, CNRS
91761 Palaiseau, FRANCE
Partially supported by CARE/PHIN FP6 project
LOA
INFN, Frascati, November 16 (2006)

2. INFN, Frascati, November 16 (2006)
Summary
Part 1 : Laser plasma accelerator : motivation
Part 2 : Production of monoenergetic electron beam
Part 3 : New scheme of injection : toward a stable, tuneable and quasi monoenergetic electron beam.
Part 4 : Conclusion and perspectives
LOA
INFN, Frascati, November 16 (2006)

3. Classical accelerator limitations
E-field max ≈ few 10 MeV /meter (Breakdown)
R>Rmin Synchrotron radiation
Courtesy of W. Mori & L. da Silva
Plasma cavity
100 mm
1 m
RF cavity
LOA
INFN, Frascati, November 16 (2006)

4. INFN, Frascati, November 16 (2006)
Laser plasma injector
Scheme of principle
Experimental set up
LOA
INFN, Frascati, November 16 (2006)

5. Energy distribution improvements:
The Bubble regime
Charge in the peak : pC
Divergence = 6 mrad
Experiment
PIC
At LOA
J. Faure et al. Nature (2004)
LOA
INFN, Frascati, November 16 (2006)

6. 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
INFN, Frascati, November 16 (2006)

7. 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
INFN, Frascati, November 16 (2006)

8. INFN, Frascati, November 16 (2006)
Laser plasma injector : GeV electron beams w = 20 m t 30 fs a 4 l . 8 P
200 TW n p 1 5 × 10 18 cm - 3
After 5 Zr / 7.5 mm
0.5 1
1.5 2
2.5
800
1200
1600
2000
Energy (MeV)
f(E) (a.u.)
Courtesy of UCLA& Golp groups
LOA
INFN, Frascati, November 16 (2006)

9. INFN, Frascati, November 16 (2006)
Laser plasma injector :
+ good efficiency : Ee-beam/Elaser  10 %
+ simple device
+ with channel : GeV range is obtained1 with moderate laser power*
*But since the efficiency is conserved a compromise between charge and
energy must be found
Stability not yet demonstrated : in progress
- Energy spread still too large for some applications : dE/E  few %
* Courtesy of S. Hoocker or F. S. Tzung PRL (2004
LOA
INFN, Frascati, November 16 (2006)

10. INFN, Frascati, November 16 (2006)
Controlling the injection
pump
injection
Counter-propagating geometry:
Plasma wave
Principle:
Pump beam
electrons
Injection beam
Ponderomotive force of beatwave: Fp ~ 2a0a1/λ (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)
LOA
INFN, Frascati, November 16 (2006)

11. 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

12. INFN, Frascati, November 16 (2006)
LOA
INFN, Frascati, November 16 (2006)

13. 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
LOA
INFN, Frascati, November 16 (2006)

14. Optical injection by colliding pulses
leads to stable monoenergetic beams
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
*Charge measurements
with absolute calibration
of Lanex film (ICT gave a factor
of 8 higher charge)
LOA
INFN, Frascati, November 16 (2006)

15. Monoenergetic bunch comes from colliding pulses: polarization test
Parallel
polarization
Crossed
polarization
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INFN, Frascati, November 16 (2006)

16. Controlling the bunch energy by controlling the acceleration length
By changing delay between pulses:
Change collision point
Change effective acceleration length
Tune bunch energy
Pump beam
Injection beam
2 mm
Gas jet
LOA
INFN, Frascati, November 16 (2006)

17. 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
LOA
INFN, Frascati, November 16 (2006)

18. 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
LOA
INFN, Frascati, November 16 (2006)

19. Conclusions / perspectives
SUMMARY
Optical injection by colliding pulse: it works !
Monoenergetic beams trapped in first bucket
Enhances dramatically stability
Energy is tunable: MeV
Charge up to 80 pC in monoenergetic bunch
dE/E down to 5 % (spectrometer resolution), dE ~ 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)
LOA
INFN, Frascati, November 16 (2006)

20. LOA/CARE_PHIN : List of publications in refereed journals
16 Controlled injection and acceleration of electrons in plasma wakefields by colliding laser pulses
J. Faure, C. Rechatin, A. Norlin, A. F. Lifschitz, Y. Glinec, V. Malka, Accepted in Nature (2006)
15 Staged concept of laser plasma acceleration toward multi GeV electrons beams
V. Malka, J. Faure, Y. Glinec, A. Lifschitz, to be published to PR -STA
14 Absolute calibration for a broadrange single shot electron spectrometer
Y. Glinec, J. Faure, A. Guemnie-Tafo, V. Malka, et al., RS 2006I.
13 Ultra short laser pulses and ultra short electron bunches generated in relativistic laser plasma interaction.
J. Faure, Y. Glinec, G. Gallot, and V. Malka, Phys. Plasmas 13, (2006).
12 Design of a compact GeV Laser Plasma Accelerator
V.Malka, A. F. Lifschitz, J. Faure, Y. Glinec, NIM A 561, p (2006)
11 Wakefield acceleration of low energy electron bunches in the weakly nonlinera regime
A. F. Lifschitz, J. Faure, Y. Glinec, V. Malka, NIM A 561, p (2006)
10 Proposed Scheme for Compact GeV Laser Plasma Accelerator
A. Lifschitz, J. Faure, Y. Glinec, P. Mora, and V. Malka, Laser and Particle Beams 24, (2006)
9 Radiotherapy with laser-plasma accelerators: application of an experimental quasi-monoenergetic electron beam
Y. Glinec, J. Faure, T. Fuchs, H. Szymanowski, U. Oelfke, and V. Malka, Med. Phys. 33, (1) (2006)
8 Laser-plasma accelerator: status and perspectives
V. Malka, J. Faure, Y. Glinec, A.F. Lifschitz, Royal Society Philosophical Transactions A, 364, 1840, (2006)
7 Observation of laser pulse self-compression in nonlinear plasma waves
J. Faure, Y. Glinec, J. Santos, V. Malka, S. Kiselev, A. Pukhov, and T. Hosokai, Phys. Rev. Lett. 95, (2005).
6 Laser-plasma accelerators: A new tool for science and for society
V. Malka, J. Faure, Y. Glinec, and A.F. Lifschitz, Plasmas Physics and Controlled Fusion 47 (2005) B481-B490.
5 GeV Wakefield acceleration of low energy electron bunches using Petawatt lasers
A.F. Lifschitz, J. Faure, V. Malka, and P. Mora, Phys. of Plasmas 12, (2005).
4 Generation of quasi-monoenergetic electron beams using ultrashort and ultraintense laser pulses
Y. Glinec, J. Faure, A. Pukhov, S. Gordiendko, S. Kiselev, V. Malka, Laser and Particle beams 23, (2005).
3 Monoenergetic electron beam optimisation in the bubble regime
V. Malka, J. Faure, Y. Glinec, A. Pukhov, J.P. Rousseau, Phys. of Plasmas 12, (2005).
2 High-resolution -ray radiography produced by a laser-plasma driven electron source
Y. Glinec, J. Faure, L. Le Dain, et al., Phys. Rev. Lett.94 (2005).
1 A laser-plasma accelerator producing monoenergetic electron beams
J. Faure, Y. Glinec, A. Pukhov, et al., Nature 431, 541, 30 septembre (2004).
INFN, Frascati, November 15 (2006)