Paper |
Title |
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MOPC028 |
Experimental Layout of 30 nm High Harmonic Laser Seeding at FLASH
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127 |
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- H. Schlarb, S. Düsterer, J. Feldhaus, T. Laarmann
DESY, Hamburg
- A. Azima, J. Boedewadt, H. Delsim-Hashemi, M. Drescher, S. Khan, Th. Maltezopoulos, V. Miltchev, M. Mittenzwey, J. Rossbach, R. Tarkeshian, M. Wieland
Uni HH, Hamburg
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Since 2004, the free-electron laser FLASH at DESY has operated in the Self-Amplified Stimulated Emission mode, delivering to users photon beams with wavelengths between 6.5 nm and 40 nm. In 2009, DESY plans to install a 3.9 GHz RF acceleration section for the production of electron bunches with high peak currents (~kA), but ten times larger pulse durations (~250 fs) compared to the present configuration. The relaxed timing requirements of the new configuration make it possible to externally seed FLASH with high harmonics of an optical laser (sFLASH). The aim of the project is to study the technical feasibility of seeding an FEL at 30 nm with a stability suited for user operation. sFLASH will use 10 m of gap-tunable undulators installed in front of the fixed gap SASE-undulator. A chicane behind the seeding undulators will allow to extract the output radiation for a careful characterisation and for first pump-probe experiments with a resolution in the 10 fs range by combining FEL and seed laser pulses.
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TUPC114 |
Results from the Optical Replica Experiments in FLASH
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1332 |
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- V. G. Ziemann, G. Angelova
UU/ISV, Uppsala
- J. Boedewadt, S. Khan, A. Winter
Uni HH, Hamburg
- M. Hamberg, M. Larsson, P. M. Salen, P. van der Meulen
FYSIKUM, AlbaNova, Stockholm University, Stockholm
- F. Loehl, E. Saldin, H. Schlarb, E. Schneidmiller, M. V. Yurkov
DESY, Hamburg
- A. Meseck
BESSY GmbH, Berlin
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We present experimental results from the optical replica synthesizer, a novel device to diagnose sub-ps electron bunches by creating a coherent optical pulse in the infrared that has the envelope of the electron bunch and analyzing the latter by frequency resolved optical gating methods. Such a device was recently installed in FLASH at DESY. During an experiment period the spatial and temporal overlap of a several ps long electron bunch and a 200 fs laser pulse were achieved within an undulator. Coherent transition radiation due to the induced micro-bunching was observed on a silver-coated silicon screen and varying the timing between electrons and laser pulse produced two-dimensional images of the slices as a function of the longitudinal position within the electron bunch. In a second experiment the strongly compressed electron bunch is modulated by a laser pulse lengthened to about 2 ps and replica pulses that are emitted from a second undulator are observed and diagnosed by frequency resolved optical gating methods.
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