Title Experiences at FLASH and plans for SPARC

Title Experiences at FLASH and plans for SPARC Patrick O’Keeffe WUTA 2008, 8 th-10 th October

What I am going to talk about… ØCharacteristics of FLASH and Optical Laser ØMotivations and Scheme for Synchronisation ØMeasurement of synchronisation by Cross-correlation ØPossible experiments at SPARC Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Who am I … EU RTD project “X-Ray FEL Pump-Probe” Grant No. HPRI-CT-1999 -50009 o HASYLAB/DESY (Coordinator) o Dublin City University o CNRS / LURE Host (FEL) Synchronisation Measurements Michael Meyer Funded by the 5 th Framework Programme of the European Commission Presently: Postdoc at CNR/IMIP in group of Lorenzo Avaldi Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Layout at FLASH 250 m RF-gun Final energy Cs 2 Te - photocathode Nd: YLF pulse laser (2 -20 ps; 262 nm) 1010 electrons (1 -3 n. C) Up to 1 Ge. V SASE undulator FLASH 6 modules (each 4. 5 m) 0 = 27. 3 mm; B 0 = 0. 497 T SASE FEL Wavelength of VUV radiation 15 -50 nm, 150 m. J Patrick O’Keeffe Experimental Hall WUTA 2008, 8 th-10 th October

Time Structure of the FEL Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Optical Laser parameters Wavelength: Pulse duration: pulse energy for single laser pulse: 790 nm. . . 830 nm 100 -120 fs ~ 50 µJ (for 800 pulses in macropulse) up to 1 m. J (10 Hz pulse rep. rate) Courtesy: Ingo Will MBI (Berlin) Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Motivations for Synchronisation Motivation: Pump-probe experiments Atomic / Molecular Physics (e. g. dynamics /nonlin. processes in VUV/X-ray) Solid state dynamics (e. g. magnetization dynamics, non-thermal melting) Plasma physics (probing high electron densities) Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Synchronisation Scheme. . . hours. . . 100 ms. . . systematic drifts within the pulse changes from macropulse longterm drifts ~100 fs to macropulse > ps ~ 300 fs 1. 3 GHz and 108 MHz main oscillator Temperature stabilised Cables (300 m) pump - probe laser Klystron Injector laser experiment undulator linac electron pulse compression Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Cross Correlation in ATI of rare gases hwir =1. 55 e. V hwxuv = 26 e. V Sidebands (intensity prop. to intensity of IR) Ar(IP) 15. 76 e. V Ar(1 S 0) Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Set-up used in the Hamburg Experiments Patrick O’Keeffe WUTA 2008, 8 th-10 th October

First Experiment - 2005 Cross correlation: FEL 32. 2 nm (50 fs – 40 m. J) Laser 523 nm (12 ps – 250 m. J) Sideband Intensity = 2% of Main He line Tcross = 12. 0 +/- 0. 4 ps M. Meyer, D. Cubaynes, P. O’Keeffe, H. Luna, P. Yeates, E. T. Kennedy, J. T. Costello, P. Orr, R. Taïeb, A. Maquet, S. Düsterer, P. Radcliffe, H. Redlin, A. Azima, E. Plönjes, and J. Feldhaus PHYSICAL REVIEW A 74, 011401 R 2006 Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Second Iteration! Cross correlation: FEL 13. 8 and 25. 5 nm (15 -20 fs – 50 m. J) Laser 800 nm (120 fs – 20 m. J) Integrated Intensity of Sidebands = 20 % Tcross = 600 +/- 50 fs (FWHM) Jitter = 590 fs (FWHM) 250 fs (r. m. s. ) P. Radcliffe, et al. , Appl. Phys. Lett. 90, 131108 (2007). Patrick O’Keeffe WUTA 2008, 8 th-10 th October

SPARC vs FLASH SPARC FLASH 500 nm 15 - 45 nm Visible EUV Power 400 m. J 150 m. J Temporal Width 2 ps 10 s fs Wavelength Visible : temporal structure via autocorrelation Characteristics of SPARC similar to commercial ps YAG Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Above Threshold Ionisation with SPARC 1015 photons/pulse @ 500 nm 2 ps focussed to 50 mm 1013 W/cm 2 Mc. Ilrath et al. Phys. Rev. A 35 (1987) 4611 Patrick O’Keeffe WUTA 2008, 8 th-10 th October

IMIP Group experience SPARC Project CNR–IMIP, Poli MI, Uni. Na, Uni. Pd Science 314(2006)443 Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Seeding of SPARC Two seeding schemes mentioned in TDR produce: 53. 2 nm = 23. 3 e. V 32 nm = 38. 7 e. V Optically based autocorrelation methods become difficult Pulses on the 10 s fs – 100 fs scale Could use cross-correlation methods for characterisation of the temporal structure of the FEL Patrick O’Keeffe WUTA 2008, 8 th-10 th October

Dynamics of Excited Ionic States State of the art of gas phase pump-probe: Soft X-ray–Driven Femtosecond Molecular Dynamics Murnane and Kapteyn and coworkers: Science 317, 1374 (2007); Photons /pulse Patrick O’Keeffe HHG Seeded SPARC ~106 - 107 WUTA 2008, 8 th-10 th October

Acknowledgements Michael Meyer Members of the “X-Ray FEL Pump-Probe” EU RTD project Lorenzo Avaldi, Paola Bolognesi, Roberto Flammini Patrick O’Keeffe WUTA 2008, 8 th-10 th October