Paper |
Title |
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WEOAM02 |
A Scheme for Stabilization of Output Power of an X-ray SASE FEL
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1947 |
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- E. Schneidmiller, G. Geloni, E. Saldin, M. V. Yurkov
DESY, Hamburg
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Stability of XFEL radiation is naturally linked to stability of the linac RF system through bunch compression, leading to very tight requirements on RF amplitude and phase. We propose a new scheme that allows to relax these requirements by a large factor.
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Slides
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WEPC118 |
Study of Controllable Polarization SASE FEL by a Crossed-planar Undulator
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2282 |
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- B. Faatz, Y. Li, J. Pflueger, E. Saldin, E. Schneidmiller, M. V. Yurkov
DESY, Hamburg
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A potential and economical access to generate arbitrary polarized XFEL is to utilize crossed-undulator scheme instead of helical undulators. In this paper, the polarization of x-ray radiation for the European XFEL is investigated. The degree of polarization and the Stokes parameters are calculated for different configurations. The shot-to-shot fluctuation of polarization and the degree of polarization distribution over the transverse plane are also studied.
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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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THPC157 |
A Simple Method for Timing an XFEL Source to High-power Lasers
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3357 |
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- G. Geloni, E. Saldin, E. Schneidmiller, M. V. Yurkov
DESY, Hamburg
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We propose a technique for timing an XFEL to a high-power laser with femtosecond accuracy. The same electron bunch is used to produce an XFEL pulse and an ultrashort optical pulse that are, thus, naturally synchronized. Cross-correlation techniques will yield the relative jitter between the optical pulse (and, thus, the XFEL pulse) and a pulse from an external pump-laser with femtosecond resolution. Technical realization will be based on an optical replica synthesizer (ORS) setup to be installed after the final bunch-compressor. The electron bunch is modulated in the ORS by an external optical laser. Travelling through the main undulator, it produces the XFEL pulse. Then, a powerful optical pulse of coherent edge radiation is generated as the bunch passes through a long straight section and a separation magnet downstream of the main undulator. Relative synchronization of these pulses is preserved using the same mechanical support for X-ray and optical elements transporting radiation to the experimental area, where single-shot cross-correlation between optical pulse and pump-laser pulse is performed. We illustrate our technique with numerical examples referring to the European XFEL.
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