Keyword: timing
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MOCO04 Overview of Bunch-Resolved Diagnostics for the Future BESSY VSR Electron-Storage Ring diagnostics, electron, operation, storage-ring 49
 
  • G. Schiwietz, J.G. Hwang, M. Koopmans, M. Ries
    HZB, Berlin, Germany
 
  The upgrade of the BESSY II light source in Berlin towards the Variable pulse-length Storage-Ring BESSY VSR will lead to a complex fill pattern. This involves co-existing electron bunches with significant variations of bunch-length, bunch charge as well as charge density. Among many other boundary conditions, this calls for bunch resolved measurements with sub-ps time resolution and micrometer spatial resolution. Currently, we are constructing a diagnostic platform connected to three new dipole beamlines for visible light as well as THz measurements. The mid-term aim is a 24/7 use of beam-diagnostic tools and the development of advanced methods for specific purposes. Recently, we have set-up a sub-ps streak camera* and we are investigating other innovative methods for bunch-length** as well as lateral size determination using visible light*** at the first of our new diagnostic dipole beamlines. Preliminary results as well as our concepts for achieving high sensitivity, good signal-to-noise ratio and time resolution will be presented and discussed at the conference.
* G.Schiwietz et al., J.Phys.:Conf. Series 1067, 072005 (2018)
** T.Mitsuhashi, M.Tadano, Proc. of EPAC’02, Paris, France, p. 1936
*** J.Breunlin et al., NIM- A803, pp.55 (2015) &refs. therein
 
slides icon Slides MOCO04 [10.924 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOCO04  
About • paper received ※ 04 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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MOPP028 Longitudinal Bunch-by-Bunch Feedback Systems for SuperKEKB LER feedback, kicker, operation, damping 158
 
  • M. Tobiyama, J.W. Flanagan, T. Kobayashi, S. Terui
    KEK, Ibaraki, Japan
  • J.D. Fox
    Stanford University, Stanford, California, USA
 
  Longitudinal bunch-by-bunch feedback systems to suppress coupled bunch instabilities with minimum bunch spacing of 2 ns have been constructed in SuperKEKB LER. Through the grow-damp and excite-damp experiments with several filling patterns and the transient-domain analysis of unstable modes, the behaviors of possible impedance sources have been evaluated. The measured performance of the system, together with the performance of the related systems such as slow phase feedback to the reference RF clock are reported.  
poster icon Poster MOPP028 [0.519 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-MOPP028  
About • paper received ※ 03 September 2019       paper accepted ※ 08 September 2019       issue date ※ 10 November 2019  
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TUPP002 Direct-Sampling Coarse Bunch Arrival Time Monitor in the Free Electron Laser FLASH Based on the Fast Digitizer Implemented in the FMC VITA 57.1 Standard FEL, pick-up, electron, laser 270
 
  • J. Zink, M.K. Czwalinna, M. Fenner, S. Jabłoński, J. Marjanovic, H. Schlarb
    DESY, Hamburg, Germany
  • F. Gerfers
    Technische Universität Berlin, Berlin, Germany
 
  At the free-electron lasers FLASH and European-XFEL bunch arrival times are monitored with a high-accuracy electro-optical based data acquisition system (BAM). Due to only a couple of picoseconds time measurement range of this system, large timing changes might cause the monitor to fail. To remove any ambiguity and for health status monitoring a high-speed direct-sampling FPGA mezzanine card (FMC) and an analogue RF front-end was added. The circuitry has lower precision than the electro-optical based BAM, but it can determine bunch arrival time with respect to a reference signal over a large time range, i.e. of the order of 1 ms. After restarts or larger energy changes during operation, the electron bunch arrival time may have been changed by tens or even hundreds of picoseconds, which causes that the BAM is out of its operation range and needs to be recalibrated. With the solution developed, the BAM gets the coarse bunch timing from the digitizer and adjusts its optical delay lines accordingly. This allows for finding the operation point fast and automatically. Performance data of the fast direct-sampling digitizer FMC and first measurement data from FLASH will be presented.  
poster icon Poster TUPP002 [3.810 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP002  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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TUPP004 High-Speed Beam Signal Processor for SHINE cavity, FPGA, SRF, interface 278
 
  • L.W. Lai, Y.B. Leng
    SSRF, Shanghai, People’s Republic of China
 
  A CW hard X-ray FEL is under construction in SSRF, which pulse rate is designed to 1MHz. A new high-speed sampling BPM signal processor is under development to meet the high performance requirements of beam position measurement system. The processor’s sampling rate can be up to 500MHz, and beam position information of each bunch (1MHz rate) can be retrieved with the power of FPGA. Time stamp is aligned with the position data for offline analysis. The processor is designed to be a common signal processing platform for beam diagnostics. The first application is cavity BPM, and other applications, including button BPM, stripline BPM, and even wire scanner processor will be developed based on this platform. At the same time, a RF direct sampling processor is designed for cavity BPM signal processing. This novel technology will greatly simplify the cavity BPM electronic system, and make the system design more efficient and more flexible.  
poster icon Poster TUPP004 [0.983 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP004  
About • paper received ※ 04 September 2019       paper accepted ※ 07 September 2019       issue date ※ 10 November 2019  
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TUPP010 A Fast Wire Scanner System for the European XFEL FEL, operation, detector, optics 299
 
  • T. Lensch, B. Beutner, T. Wamsat
    DESY, Hamburg, Germany
 
  The European-XFEL is an X-ray Free Electron Laser facility located in Hamburg (Germany). The 17.5 GeV superconducting accelerator will provide photons simultaneously to several user stations. Currently 14 Wire Scanner stations are used to image transverse beam profiles in the high energy sections. These scanners provide a slow scan mode for beam halo studies and beam optics matching. When operating with long bunch trains (>100 bunches) fast scans will be used to measure beam sizes in an almost non-destructive manner. This paper briefly describes the wire scanner setup and focusses on the fast scan concept and first measurements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-TUPP010  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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WEPP020 First results on Femtosecond Level Photocathode Laser Synchronization at the SINBAD Facility laser, electron, controls, linac 557
 
  • M. Titberidze, M. Felber, T. Kozak, T. Lamb, J. Müller, H. Schlarb, S. Schulz, C. Sydlo, F. Zummack
    DESY, Hamburg, Germany
 
  SINBAD, the "short-innovative bunches and accelerators at DESY" is an accelerator research and development facility which will host various experiments. SINBAD-ARES linac is a conventional S-band linear accelerator which will be capable of producing ultra-short electron bunches with duration of few femtoseconds and energy of up to 100 MeV. In order to fully utilize the potential of ultra-short electron bunches while probing the novel acceleration techniques (e.g. external injection in LWFA), it is crucial to achieve femtosecond level synchronization between photocathode laser and RF source driving the RF gun of the ARES linac. In this paper we present the first results on the synchronization of the near-infrared photocathode laser to the RF source with the residual timing jitter performance of ~10 fs rms. These results were obtained using a conventional laser-to-RF synchronization setup employing heterodyne detection of an RF signal generated by impinging the laser pulses to a fast photodetector. In addition, we describe an advanced laser-to-RF phase detection scheme as a future upgrade; promising even lower timing jitter and most importantly the long-term timing drift stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2019-WEPP020  
About • paper received ※ 04 September 2019       paper accepted ※ 10 September 2019       issue date ※ 10 November 2019  
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