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- M.-E. Couprie, M. Labat, G. Lambert, O. V. Chubar
SOLEIL, Gif-sur-Yvette
- O. Tcherbakoff
CEA, Gif-sur-Yvette
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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.
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Slides
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