SEEDING EXPERIMENTS AT SPARC Luca Giannessi ENEA C.R. Frascati On behalf of the SPARC collaboration International Conference on Charged and Neutral Particles Channeling Phenomena, 4-8 October 2010, Ferrara, Italy

L.G., A. Petralia, G. Dattoli, F. Ciocci, M. Del Franco, M. Quattromini, C. Ronsivalle, E. Sabia, I. Spassovsky, V. Surrenti ENEA C.R. Frascati, IT. D. Filippetto, G. Di Pirro, G. Gatti, M. Bellaveglia, R. Boni, D. Alesini, M. Castellano, E. Chiadroni, L. Cultrera, M. Ferrario, L. Ficcadenti, A. Gallo, A, Ghigo, E. Pace, B. Spataro, C. Vaccarezza, INFN-LNF, IT. A. Bacci, V. Petrillo, A.R. Rossi, L. Serafini INFN-MI, IT. M. Serluca, M. Moreno INFN-Roma I, IT. L. Poletto, F. Frassetto CNR-IFN, IT. J.V. Rau, V. Rossi Albertini ISM-CNR, IT. A. Cianchi, UN-Roma II TV, IT. A. Mostacci, M Migliorati, L. Palumbo, Un. Roma La Sapienza, IT. G. Marcus, P. Musumeci, J. Rosenzweig, UCLA, CA, USA. S. Spampinati, ST, IT and University of Nova Gorica, Nova Gorica, M. Labat, F. Briquez, M. E. Couprie, SOLEIL, FR. B. Carré, M. Bougeard, D. Garzella CEA Saclay, DSM/DRECAM, FR. G. Lambert LOA, FR. C.Vicario PSI, CH. Contributors L. Giannessi, Channeling 2010

Seeded SPARC Layout Ti:Sa Regenerative Amplifier HHG generation Chamber Periscope & injection chicane In vacuum spectrometer nm + MUR L. Giannessi, Channeling 2010

Infrared L. Giannessi, Channeling 2010 Dec InfraredGAS Cell Differential vacuum to Undulators Focusing mirrors

Seeded Operation Seed FEL Amplifier FEL Harmonic Generation Seed 1 ModulatorRadiator 2 = 1 /n, n=2 Seed Sources: –400 nm in BBO crystal (high seed energy) –266 nm & 160 nm generated in gas Cascaded FEL tested with both seed configurations Seed FEL Amplifier Seed FEL Amplifier L. Giannessi, Channeling 2010

266 nm generated in Ar, ~50 nJ (±20nJ) 6 UM 266 nm Spectrometer 5 um - CCD saturated with nb 266nm, 17% T Seed FEL Amplifier Amplification 20x L. Giannessi, Channeling 2010

Delay line Scan Adjustable delay up to 4m Delay line

Cascaded FEL FEL Harmonic Generation Seed 1 ModulatorRadiator 2 = 1 /n, n=2 266 nm, 50 nJ UM 266 nm – UM nm L. Giannessi, Channeling 2010

FEL Harmonic Generation Seed 1 ModulatorRadiator 2 = 1 /n, n=2 FEL Harmonic Generation Seed 1 ModulatorRadiator 2 = 1 /n, n=2

L. Giannessi, Channeling 2010 (2010/06/04) 160nm Seed intensity & SASE too low to be detected at the spectrometer (< 1 nJ) Seed intensity & SASE too low to be detected at the spectrometer (< 1 nJ) The 266 measured 1 day before shows the same double peak structure Seeded FEL – 4 nJ

L. Giannessi, Channeling 2010 Effect of high intensity seed GENESIS Simulation Seed Energy < 0.5 uJ ~ 0.7 uJ ~ 3 uJ ~ 9 uJ

Seeded FEL: field intensity above saturation Simulation with Perseo ( L. Giannessi, Channeling 2010

Bunching coefficients in the front side of the pulse Expected very efficient generation of high order harmonics L. Giannessi, Channeling 2010

Harmonics in a Superradiant pulse Short bunching peaks on the pulse front side at the higher order harmonics Short bunching peaks on the pulse front side at the higher order harmonics Dynamics for non-linear harmonic evolution faster by the harmonic factor n. (i.e. L g,n ~ L g /n ) Dynamics for non-linear harmonic evolution faster by the harmonic factor n. (i.e. L g,n ~ L g /n ) Short bursts of harmonic radiation Short bursts of harmonic radiation Pulse structre preserved by the solitary wave behavior of this solution Pulse structre preserved by the solitary wave behavior of this solution Harmonic emission suppressed by energy spread Harmonic pulse L. Giannessi, Channeling 2010

High harmonics down to 37 nm Observation of 11° harmonic at 37nm 11h 10h 9h 8h 7h 6h 5h 4h 3h 2h 1h Measured energy per pulse, spot size & and bandwidth of the first 11° harmonics

High intensity seed in a cascaded configuration Seed 1 = 400nm ModulatorRadiator 2 = 200 nm 200 nm 3° harmonic of the radiator (66nm ~ 100 nJ) Effect of high intensity seed Energy jitter mainly due to e-beam energy jitter L. Giannessi, Channeling 2010

Correlations Large energy jitter –> large energy fluctuations Correlation Energy – Spot size Correlation Energy – Linewidth Redshift Structure in the spectrum Indication of nm L. Giannessi, Channeling 2010

3h of the radiator 66 nm L. Giannessi, Channeling 2010

Conclusions (From Channeling 2006) SPARC represents a unique opportunity for studying single pass FEL and FEL cascades in seeded mode SPARC represents a unique opportunity for studying single pass FEL and FEL cascades in seeded mode Conventional lasers and FEL are merged in a single device Conventional lasers and FEL are merged in a single device New experiments are foreseen in the next future New experiments are foreseen in the next future The harmonic cascade The harmonic cascade Multistage cascade and the Fresh Bunch injection technique Multistage cascade and the Fresh Bunch injection technique Superradance in a cascade and the harmonic cascade Superradance in a cascade and the harmonic cascade FEL amplification from a gas HHG source/harmonic generation FEL amplification from a gas HHG source/harmonic generation These new schemes extend the foreseen SPARC spectral range to 44nm nm These new schemes extend the foreseen SPARC spectral range to 44nm nm The experience resulting from those experiments will provide the confidence to extend the seeded FEL cascade wavelength operation range in higher beam energy devices as SPARX ok In progress tru e 37 nm