1. FLAME, STATO DEL COMMISSIONING E SELF-INJECTION TEST EXPERIMENT
Leonida A. GIZZI
Istituto Nazionale di OTTICA - CNR, Pisa, Italy
& INFN, Pisa/LNF, Italy
On behalf of the PLASMONX/FLAME Team

2. People and institutions
F. Anelli(1), A. Bacci (10), D. Batani (4), M. Bellaveglia (1), C. Benedetti(5,6,*), R. Benocci (4), L. Cacciotti (1), C.A Cecchetti(2,3), O. Ciricosta (2,8), A. Clozza(1), L. Cultrera (1), G.Di Pirro(1), N. Drenska(7,8), R. Faccini(7,8), M. Ferrario (1), D. Filippetto(1), A. Gallo (1), S.Fioravanti(1), A. Gamucci(2,3), G. Gatti (1), A. Ghigo (1), A. Giulietti(2,3), D. Giulietti(1,2,3,9), P. Koester (2,3), L. Labate(2,3), T. Levato(1,2), V. Lollo(1), E. Pace(1), N. Pathack (2,9), A.R. Rossi (10), L. Serafini(10), G. Turchetti(5,6), C. Vaccarezza(1), P. Valente(7).
(1) LNF, INFN, Frascati, Italy,
(2) ILIL-INO, CNR, Pisa, Italy,
(3) Sez. INFN, Pisa, Italy,
(4) Dip. di Fisica, Univ. Milano-Bicocca, e INFN-Mi, Italy,
(5) Dip. di Fisica, Univ. di Bologna, Italy,
(6) Sez. INFN Bologna, Bologna, Italy,
(7) Sez. INFN Roma-1, Roma, Italy,
(8) Dip. Fisica, Univ. La Sapienza, Roma, Italy,
(9) Dip. di Fisica, Univ. di Pisa, Italy,
(10) Sez. INFN, Dip. Fisica, Univ. Milano, Italy
* Now at LBNL, USA

3. contents REMINDER ON MOTIVATIONS FLAME: STATUS
TEST EXPERIMENT ON LPA w. SELF-INJECTION
CONCLUSIONS

4. Motivation: PLASMONX
PLASma acceleration and MONochromatic X-ray radiation: a project of the Commission on “Nuove Tecniche di Accelerazione (NTA)”.
COMBINING THE HIGH BRIGHTNESS BUNCHES OF THE SPARC LINAC WITH THE ULTRA-SHORT PULSES OF THE FLAME LASER.
Scheduled activity:
TUNEABLE, MONOCROMATIC X-RAY SOURCE BASED UPON THOMSON SCATTERING FROM INTERACTION OF LASER PULSES WITH:
LINAC e-bunches;
LWFA e-bunches (all-optical scheme);
LASER-PLASMA ACCELERATION (USING WAKEFIELDS):
self-injected electrons ;
External injection of SPARC electron bunches;
Intense laser-matter interactions, proton acceleration.

5. PROJECT UNITS LNF, INFN, Frascati & Roma 1 INFN
MILANO INFN (Bicocca and Celoria)
BOLOGNA INFN
PISA INFN and INO– CNR
LNF, INFN, Frascati
& Roma 1 INFN
NAPOLI INFN
LNS, INFN

6. X-ray source 1/2: using sparc bunches
Tuneable X-ray radiation source based on Thomson Scattering using FLAME pulses and SPARC bunches;
from SPARC
from FLAME
Interaction point
Design completed. Construction in progress: Experiments starting mid-2011

7. X-RAY SOURCE 1/2: ALL OPTICAL SCHEME
Generate tuneable X-ray radiation from counterpropagating laser-accelerated electrons (LWFA and self injexction) and laser pulse
FLAME laser pulse
e- bunch from LWFA
X-rays
Gas-jet target
Integrated design in progress. Will build on success of LPA experiments.

8. Acceleration with self-injection
GeV electron acceleration in gases using LWA of self-injected electrons.
Also a test experimentl for the FLAME commissioning.
Construction completed: Experiments starting mid-2010

9. LPA with external injection
LWFA acceleration of externally injected electrons in a gas-jet plasma
Design in progress: Experiments starting 2012

10. FLAME STATUS

11. Schematic block diagram

12. FLAME LAB: OVERVIEW
FLAME LAB INCLUDES LASER INSTALLATION AND RADIOPROTECTED TARGET AREA FOR LASER-TARGET EXPERIMENTS. TRANSPORT OF LASER TO SPARC FOR LASER-LINAC OPERATION IS ALSO IS INCLUDED
TRANSPORT
TO SPARC
TARGET AREA
LASER INSTALLATION

13. FLAME: key parameters
FLAME to operate a 250 TW, 10 Hz system
Basic issues/challenges (project driven):
Pulse contrast (>1010)
Pulse duration (<30 fs)
Performance stability to compare with LINAC
Mechanical stability (2 µm at focal spot) …

14. Project laser requirements

15. Critical technology ISSUES
CONTRAST
Temporal contrast (ASE) in excess of 10 orders of mag. required for peak intensities on target of >1022 W/cm2.
Established techniques include
electro-optic devices (Pockel cells) for prepulse reduction;
moderate gain in fromt end and saturable amplifier for ASE management;
Other advanced techniques (e.g cross polarized wave generation) again for front-end contrast enhancement;

16. LATEST CONTRAST MEASUREMENTS
Best pulse duration (<25 fs)
(with Mazzler loop)
“Natural” pulse duration (<55 fs)
Contrast well within specs;

17. COMPRESSION COMPLETED
Periscope
Big Grating
Corner cube
Little Grating
Output
Input
PH53
PH51
PH52
Efficiency of the vacuum compressor >70%
Pulse duration with the test compressor
Spider measurements
natural duration < 55 fs
corrected duration < 25 fs

18. SUMMARY OF FLAME LASER Summary of performance (to date)
Energy before 7 J
Vacuum compressor transmission > 70%
Pulse duration down to 23 fs
ASE Contrast ratio: better than 2x109
Pre-Pulse Contrast better than 108
RMS Pulse 0.8 %
Pointing Stability (incl. path) < 2µrad
Enhancement of pumping configuration/extraction efficiency;
Full vacuum compression test to be performed at LNF shortly;

19. LASER-PLASMA ACCELERATION WITH Self-Injection A test experiment (S. I
LASER-PLASMA ACCELERATION WITH Self-Injection A test experiment (S.I.T.E.)

20. GeV ACCELERATION WITH SELF INJECTION
Main set up parameters
See: L.A. Gizzi et al., EPJ-ST, 175, 3-10 (2009)

21. PIC CORE (PSC) RUNS FOR S.I.T.E.
MORE MODELLING IN PROGRESS …
by N.Pathak, L.Labate, T. Levato …
Need to run for longer axial and transverse length

22. Numerical simulations
Goal: 0.9 GeV in 4 mm

23. FLAME target area (for S.I.T.E.)

24. SCHEMATIC EXPERIMENTAL SET UP
THOMSON 90°‏
Side view
NaI+PM
Scattering/image
Spectrometer
(LANEX out)
Spectrometer
Gas jet
Scintillator screen (LANEX)‏
Top View
Main Laser Beam
Nozzle
Fast Valve
MeV electron
bunch
NaI+PM
PROBE BEAM
(400 nm, <25fs, <50 mJ)‏
MAIN BEAM with F/10 off-axis parabola
Wavelength: 800 nm
Pulse duration and energy: <25 fs
Focal Spot diameter (FWHM): 13.5 µm
Depth of focus: < 250 µm
Max Intensity(per Joule of energy): 5x1019 W/cm2
Nozzle slit
Delay line
Off-axis
parabolic mirror

25. FLAME TARGET AREA
Main beam (>250 TW)
acuum transport line

26. FLAME TARGET AREA Radiation protection walls Main beam (>250 TW)
Vacuum transport line
Beam transport to sparc bunker
Interaction
vacuum
chamber
Compressor
vacuum chamber

27. FLAME TARGET AREA Main beam (>250 TW) Vacuum transport line
Radiation protection walls
Interaction point
Main turning mirror
Off-axis
parabola
Interaction
vacuum chamber
Electron
spectrometer

28. FLAME TARGET AREA (SITE)

29. Vert. and Horiz. Shielding

30. MAIN BEAM OPTICS IN PLACE
45 AND 15° TURNING MIRROR MOUNTED

31. Focusing laser
1 m focal length, 15° Off Axis Parabola (SORL)

32. LASER AT TARGET CHAMBER CENTER
Pointing stability at TCC

33. GAS JET TARGET IN PLACE

34. MILESTONSE FOR SELF INJECTION
Start acceleration of electrons with self-injection;
Establish control of laser parameters on electron acceleration including:
Pulse contrast, duration and stability;
Focal spot quality and Strehl ratio.
Characterize electron bunches: energy, energy spread, emittance, bunch charge;
Optimize quality and stability for applications.

35. Agenda for next weeks
Full power FLAME test: transport, compression, OAP focusing (no target);
Laser performance test at output: far field, contrast, width, phase distortion, measurements … prepare for adaptive optics;
Completion and and test of HW and SW control and diagnostics;
Completion of hardware and registration for radioprotection, safety and control of operations;
Laser on (gas-jet) target at >50 TW level.

36. Planned activity 2/2

37. summary
FLAME commissioning entering experiment phase;
Requirements on peak power, contrast, stability are challenging;
Measurements to date show that parameters are within specs;
Radiation protection measures in place – awaiting authorization
Rapidly approaching self-injection LPA measurements

38. THE END