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

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

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

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.

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

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

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.

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

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

FLAME STATUS

Schematic block diagram

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

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) …

Project laser requirements

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;

LATEST CONTRAST MEASUREMENTS Best pulse duration (<25 fs) (with Mazzler loop) “Natural” pulse duration (<55 fs) Contrast level@200mJ well within specs;

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

SUMMARY OF FLAME LASER Summary of performance (to date) Energy before compression @ 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 Stability @ 0.8 % Pointing Stability (incl. path) < 2µrad Enhancement of pumping configuration/extraction efficiency; Full vacuum compression test to be performed at LNF shortly;

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

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

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

Numerical simulations Goal: 0.9 GeV in 4 mm

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

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

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

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

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

FLAME TARGET AREA (SITE)

Vert. and Horiz. Shielding

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

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

LASER AT TARGET CHAMBER CENTER Pointing stability at TCC

GAS JET TARGET IN PLACE

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.

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.

Planned activity 2/2

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

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