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WG503 |
Synchronization System for the XFEL
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- H. Schlarb, F. Loehl, F. Ludwig, S. Simrock
DESY, Hamburg
- F. X. Kaertner, J. Kim
MIT, Cambridge, Massachusetts
- A. Winter
Uni HH, Hamburg
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The production of ultra-short electron bunches in Free Electron Lasers puts complete new demands on the sychronisation systems for the accelerator and its sub-system. Novel new techniques using laser pulses, distributed in optically stabilized fiber-links, provide the possibility to synchronize with femtosecond stability critical components such as mode-locked lasers for pump-probe experiments, or diagnostic purposes, and local RF oscillators for the LLRF controls to the machine reference. In this talk an overview of the layout for the XFEL synchronization system and its sub-components is given.
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WG504 |
Recent Developments and Layout of the Master Laser System for the VUV-FEL
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- A. Winter, H. Schlarb
DESY, Hamburg
- F. O. Ilday
Bilkent University, Bilkent, Ankara
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Mode-locked fiber lasers are promising candidates to serve as optical master oscillators in optical synchronization systems. This talk will present recent measurements regarding the phase noise of these lasers. Furthermore, the layout of the optical master oscillator for the VUV-FEL will be discussed and first results concerning its reliability will be presented.
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Slides
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WG506 |
Compact Ultra-High Precision Beam Phase Monitor System
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- F. Loehl, K. E. Hacker, F. Ludwig, H. Schlarb, B. Schmidt
DESY, Hamburg
- A. Winter
Uni HH, Hamburg
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For the operation of free-electron lasers, in particular for experiments carried out in pump-probe configurations, a precise synchronization between the photo-injector laser, low-level RF-systems, probe lasers, and other components is mandantory. A measurement of the jitter in the arrival-time of the electron bunch with respect to the clock signal of a master oscillator is, therefore, of special importance. We present an ultra-precise arrival-time monitor system based on a broadband beam pick-up which permits measurements in the sub-100 fs regime. With the inductively shaped RF-pulse from the beam pick-up the amplitude of an ultra-short laser pulse is modulated using an electro-optical modulator with appropriate bandwidth. This modulation is detected by a photo detector and sampled by a fast ADC. As sampling laser the master laser oscillator of the machine is used directly. Therefore, no additional devices are required that may add timing jitter. We present the layout of the system and first experimental results.
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Slides
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WG511 |
Time-Resolved Measurements using a Transversely Deflecting RF-Structure
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- M. Roehrs, C. Gerth, H. Schlarb
DESY, Hamburg
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In SASE-based Free Electron Lasers as FLASH at DESY, the knowledge of time-related parameters of electron bunches as bunch length, energy-time correlation and time-sliced emittance is important for FEL-operation and for analysing bunch compression processes. In order to measure such parameters, a vertically deflecting rf-structure has been installed at FLASH and taken into operation in early 2005. The structure allows to establish the longitudinal density profile of single bunches on the vertical axis of an OTR-screen. The horizontal time-sliced emittance can be reconstructed from measurements of the slice widths for different quadrupole settings. By dispersing vertically streaked bunches horizontally with a dipole, the energy-time correlation can be directly obtained in a single shot measurement. In this paper some results of recent measurements are presented.
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Slides
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WG513 |
Status of the Optical Replica Synthesizer Project at DESY
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- V. G. Ziemann
UU/ISV, Uppsala
- M. Larsson, P. van der Meulen
FYSIKUM, AlbaNova, Stockholm University, Stockholm
- E. Saldin, H. Schlarb, E. Schneidmiller, M. V. Yurkov
DESY, Hamburg
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We present the status of the optical replica synthesizer project to measure ultra-short electron bunches in the VUV-FEL. The device is based on the creation and diagnosis of a coherent light pulse that mimics the longitudinal profile of the electron bunch as described by Saldin, et.al. in Nuclear Inst. and Meth. A 539 (2005) 449.
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Slides
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WG523 |
Large Aperture BPM for use in Dispersive Regions of Magnetic Chicanes
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- K. E. Hacker, N. Baboi, F. Loehl, D. Noelle, H. Schlarb
DESY, Hamburg
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A beam position monitor with a large horizontal aperture is being developed for use in dispersive regions of magnetic chicanes as part of an energy measurement. It will have a horizontal detection range of 16 cm and a resolution of better than 30 μm. This is achievable with a stripline design, mounted perpendicularly to the electron beam direction. A high-precision phase measurement at both ends of the stripline will allow for determination of the beam postion. The phase measurement of the short RF pulses from the stripline will be done with a technique that utilizes a timing laser that samples the RF pulse traveling though an electro-optical modulator.
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