Chubar, O. V.

Paper	Title	Page
MOAAU01	First Lasing in Seeding Configuration at 160 nm Using High order Harmonic Generated in gas on the FEL of the SCSS Prototype Accelerator
	B. Carré, D. Garzella, O. B. Gobert, M. Labat, H. Merdji, P. Salieres, G. Lambert CEA, Gif-sur-Yvette O. V. Chubar, M.-E. Couprie SOLEIL, Gif-sur-Yvette T. Hara, H. Kitamura, T. Shintake, K. Tahara, Y. T. Tanaka RIKEN Spring-8 Harima, Hyogo S. Inoue JASRI/SPring-8, Hyogo-ken T. Tanikawa University of Hyogo, Hyogo
	Coherent radiation has been observed at 160 nm, 54 nm and 32 nm (respectively fundamental, 3rd and 5th non linear harmonics) by seeding the 5th harmonic of a Ti: Sa laser (800 nm, 50 mJ, 10 Hz, 100 fs) generated in a Xe gas cell inside the FEL of the SCSS (SPring-8 Compact Sase Source, Japan) Prototype Accelerator. In this configuration, the external source is focalized at the beginning of the first in-vacuum undulator section (300 periods, 15 mm of period) in order to interact properly with the electron beam (150 MeV, 0.3 nC, 10 Hz, 1 ps). The details of the experimental set-up will be given. With one undulator section, high amplification levels and shortening of the spectral width compared to the spontaneous emission have been measured. When adding the second undulator section, saturated signal is apparently observed. The measurements are then compared with time dependant simulations using PERSEO and GENESIS included in SRW. Finally, perspectives offered by seeding an FEL with High order Harmonics Generated in gas, following this first experimental demonstration, will be derived for 4th generation light sources in the soft X-ray range.
MOCAU03	Numerical Propagation Simulations and Coherence Analysis of SASE Wavefronts	192
	M.-E. Couprie, M. Labat, G. Lambert, O. V. Chubar SOLEIL, Gif-sur-Yvette O. Tcherbakoff CEA, Gif-sur-Yvette
	Examples of wavefront propagation simulation and coherence analysis of SASE, seeded and started-up from noise, are presented. The calculations are performed using SRW – the wave-optics computer code optimized for synchrotron radiation, and the 3D FEL simulation code GENESIS 1.3. To ensure easy inter-operation and data exchange between the two codes, GENESIS has been integrated into the "emission" part of the SRW, which is dedicated for calculation of initial wavefronts in the form ready for subsequent propagation simulations. In the examples described, after each run of GENESIS in time-dependent mode, the electric field is transformed from time to frequency domain, and the wavefront obtained this way is numerically propagated, using Fourier-optics methods implemented in the SRW, from the exit of the FEL undulator to image plane of a simple interferometer-type optical scheme. Intensity-averaged patterns, obtained after multiple cycles of the SASE (in presence of shot noise and/or a timing jitter) and the wavefront propagation calculations, allow for straightforward characterization of spatial coherence by visibility of interference fringes. SRW code can also be used for complete optimization of optical beamlines for 4th generation synchrotron radiation sources, which require accurate treatment of wave-optical phenomena in the frequency and time domains.
	Slides
TUPPH007	Spatial Coherence Measurement of UVSOR-II Free Electron Laser
	O. V. Chubar, M.-E. Couprie SOLEIL, Gif-sur-Yvette K. Fukui University of Fukui, Fukui M. Hosaka Nagoya University, Nagoya M. Katoh, A. Mochihashi, M. Shimada UVSOR, Okazaki G. Lambert RIKEN Spring-8, Hyogo M. Labat CEA, Gif-sur-Yvette
	The well defined phase relationship of coherent radiation is wished for a large number of experiments. The advent of very small emittance electron beams allowed improvement of the transverse coherence of the undulators radiation and lead to extensive use of modern synchrotron facilities in the visible to x-ray domain. Nevertheless, Free Electron Lasers (in particular in the seeded Coherent Harmonic Generation (CHG) scheme) may offer additional capabilities such as shorter pulse duration, smaller spectral bandwidth, higher peak power and improved transverse coherence. Transverse coherence of the third Coherent Harmonic has been studied on the UVSOR-II storage ring (Japan) at 600 MeV, using a 2.5 mJ, 1 kHz, 1.2 ps Ti:Sa laser at 800 nm wavelength with the double slit method. The improvement of the transverse coherence of the FEL radiation compared to spontaneous emission is shown via the visibility of the interference pattern resulting from double slits. The experimental results are compared to analytical calculations as well as to 3D FEL and wavefront propagation simulations performed with SRW.
FRAAU01	Source of Radiation on ARC-EN-CIEL Proposal	505
	O. V. Chubar, M. Labat, G. Lambert, O. Marcouillé, M.-E. Couprie SOLEIL, Gif-sur-Yvette
	The ARC-EN-CIEL project proposes a panoply of light sources for the scientific community. The phase 1 (220 MeV superconducting Linac, down to 30 nm) and phase 2 (1 GeV, down to 1 nm) choice to provide 30-100 fs HGHG radiation and their Non Linear Harmonics seeded with the High order Harmonics generated in Gas is further confirmed with the suceesfull demonstration experiment of such a scheme at SPA. New optimizations of the undulatros lead to in vacuum undulators of period 26 mm for the modulator, and APPLE-type radiators of period 30 mm, close to the standard SOLEIL insertion devices. New calculations have been carried out using PERSEO TD and GENESIS coupled to SRW for further propagation of the FEL wavefront to the beamlines. In addition, THz radiation from the magnets of the compression chicanes will be provided and has been calculated using SRW. ARC-EN-CIEL Phase 3 incorporates ERL loops, for hard X ray spontaneous emission above 10 keV from short period in vacuum undulators (20 mm period typically), one Soft-X ray spontaneous emission beamline using an variable polarisation undulator, and an FEL oscillator in the 10-60 nm spectral range. Recent calculations and optimisations will be presented.
	Slides