Author: Schlarb, H.
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MOP040 Implementation of MTCA.4-based Controls for the Pulsed Optical Synchronization Systems at DESY 115
  • M. Felber, Ł. Butkowski, M.K. Czwalinna, M. Fenner, C. Gerth, M. Heuer, E. Janas, M. Killenberg, T. Lamb, U. Mavrič, J.M. Müller, P. Peier, K.P. Przygoda, S. Ruzin, H. Schlarb, C. Sydlo, M. Titberidze, F. Zummack
    DESY, Hamburg, Germany
  • T. Kozak, P. Prędki
    TUL-DMCS, Łódź, Poland
  Funding: This work has partly been funded by the Helmholtz Validation Fund Project MTCA.4 for Industry (HVF-0016)
With the current state of the synchronization system at FLASH (Free-electron Laser in Hamburg) the arrival time between electron bunches and optical laser pulses can be synchronized to a level of 30 fs rms, e.g. for pump-probe experiments. In the course of the development of an up-scaled system for the European XFEL and the migration of control hardware to the modern MTCA.4 (Micro Telecommunications Computing Architecture) platform, all involved components of the system will be replaced with new developments. The front-end devices are upgraded. FPGAs (Field Programmable Gate Arrays) are performing the data processing and feedback calculations. In order to facilitate the firmware development, a toolset (Rapid-X) was established which allows application engineers to develop, simulate, and generate their code without help from FPGA experts in a simple and efficient way. A software tool kit (MTCA4U) provides drivers and tools for direct register access e.g. via Matlab or Python and a control system adapter, which allows the server applications to be written control system independent. In this paper, an overview on the synchronization setups and their upgrades as well as an introduction to the new hardware is given. The Rapid-X and MTCA4U tool kits are presented followed by a status report on the implementation of the new developments.
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TUP045 MTCA.4 Phase Detector for Femtosecond-Precision Laser Synchronization 474
  • E. Janas, M. Felber, M. Heuer, U. Mavrič, H. Schlarb
    DESY, Hamburg, Germany
  • K. Czuba
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  For time-resolved experiments at FELs such as the European XFEL an accurate synchronization of the machine is essential. The required femtosecond- level synchronization we plan to achieve with an optical synchronization system, in which an inherent part is the master laser oscillator (MLO) locked to the electrical reference. At DESY we develop a custom rear transition module in MTCA.4 standard, which will allow for different techniques of phase detection between the optical and the electrical signal, as well as locking to an optical reference using a cross-correlator. In this paper we present the current status of the development, including two basic solutions for the detection to an RF. One of the methods incorporates an external drift free detector based on the so-called MZI setup. The other one employs the currently used downconverter scheme with subsequent improvements. The module can serve for locking a variety of lasers with different repetition rates.  
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TUP049 Prototype of the Improved Electro-Optical Unit for the Bunch Arrival Time Monitors at FLASH and the European XFEL 478
  • H. Dinter, M.K. Czwalinna, C. Gerth, K.P. Przygoda, R. Rybaniec, H. Schlarb, C. Sydlo
    DESY, Hamburg, Germany
  At today's free-electron lasers, high-resolution electron bunch arrival time measurements have become increasingly more important in fast feedback systems providing accurate timing stability for time-resolved pump-probe experiments and seeding schemes. At FLASH and the upcoming European XFEL a reliable and precise arrival time detection down to the femtosecond level has to cover a broad range of bunch charges, which may even change from 1 nC down to 20 pC within a bunch train. This is fulfilled by arrival time monitors which employ an electro-optical detection scheme by means of synchronised ultra-short laser pulses. At both facilities, the new bunch arrival time monitor has to cope with the special operation mode where the MHz repetition rate bunch train is separated into several segments for different SASE beam lines. Each of the segments will exhibit individual timing jitter characteristics since they are generated from different injector lasers and can be accelerated with individual energy gain settings. In this paper, we describe the recent improvements of the electro-optical unit developed for the bunch arrival time monitors to be installed in both facilities.  
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WEP031 Measurements and Simulations of Seeded Electron Microbunches with Collective Effects 650
  • K.E. Hacker, S. Khan, R. Molo
    DELTA, Dortmund, Germany
  • S. Ackermann, J. Bödewadt, M. Dohlus, N. Ekanayake, T. Laarmann, H. Schlarb
    DESY, Hamburg, Germany
  • L.L. Lazzarino, C. Lechner, Th. Maltezopoulos, T. Plath, J. Roßbach
    Uni HH, Hamburg, Germany
  Funding: The experiments were carried out at FLASH at DESY. BMBF contract No. 05K10PE1, 05K10PE3, 05K13GU4, and 05K13PE3, and the German Research Foundation program graduate school 1355.
Measurements of the longitudinal phase-space distribution of electron bunches seeded with an external laser were done in order to study the impact of collective effects on seeded microbunches in free-electron lasers. Velocity bunching of a seeded microbunch appears to be a viable alternative to compression with a magnetic chicane under high-gain harmonic generation seeding conditions when the collective effects of Coulomb forces in a drift space and coherent synchrotron radiation in a chicane are considered. Measurements of these effects on seeded electron microbunches were performed with an RF deflecting structure and a dipole magnet which streak out the electron bunch for single-shot images of the longitudinal phase-space distribution. Particle tracking simulations in 3D predicted the compression dynamics of the seeded microbunches with collective effects.
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WEP047 Femtosecond Timing Distribution at the European XFEL 669
  • C. Sydlo, M.K. Czwalinna, M. Felber, C. Gerth, J.M. Müller, H. Schlarb, F. Zummack
    DESY, Hamburg, Germany
  • S. Jabłoński
    Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
  Accurate timing synchronization on the femtosecond timescale is an essential installation for time-resolved experiments at free-electron lasers (FELs) such as FLASH and the upcoming European XFEL. To date the required precision levels can only be achieved by a laser-based synchronization system. Such a system has been successfully deployed at FLASH and is based on the distribution of femtosecond laser pulses over actively stabilized optical fibers. For time-resolved experiments and for special diagnostics it is crucial to synchronize various laser systems to the electron beam with a long-term stability of better than 10 fs. The upcoming European XFEL has raised the demands due to its large number of stabilized optical fibers and a length of 3400 m. Specifically the increased lengths for the stabilized fibers had necessitated major advancement in precision to achieve the requirement of less than 10 fs precision. This extensive rework of the active fiber stabilization has led to a system exceeding the current existing requirements and is even prepared for increasing demands in the future. This paper reports on the laser-based synchronization system focusing on the active fiber stabilization for the European XFEL, discusses major complications, their solutions and the most recent performance results.  
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