Author: Raasch, J.
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TUPRI042 Numerical Study of the Microbunching Instability at UVSOR-III: Influence of the Resistive and Inductive Impedances 1656
SUSPSNE061   use link to see paper's listing under its alternate paper code  
 
  • E. Roussel, S. Bielawski, C. Evain, C. Szwaj
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • M. Adachi, M. Katoh, S.I. Kimura, T. Konomi
    UVSOR, Okazaki, Japan
  • M. Hosaka, Y. Takashima, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • K.S. Ilin, J. Raasch, A. Scheuring, M. Siegel, P. Thoma
    KIT, Karlsruhe, Germany
  • H. Zen
    Kyoto University, Kyoto, Japan
 
  At high charge, relativistic electron bunches circulating in storage rings undergo an instability, the so-called microbunching or the CSR (Coherent Synchrotron Radiation) instability. This instability is due to the interaction of the electrons with their own radiation and leads to the formation of microstructures (at millimeter scale) in the longitudinal phase space. Thanks to a new type of detector, based on superconducting thin film YBCO, it is now possible to observe directly these microstructures and follow their temporal evolution*. These experimental observations open a new way to make severe comparisons with theory. Here we present results of the modeling of the dynamics at UVSOR-III using a one dimensional Vlasov-Fokker-Planck equation. We show that to obtain a relatively good agreement between numerical simulations and experiments, we have to take into account several types of impedance such as the shielded CSR impedance but also the resistive and inductive impedances.
* First Direct, Real Time, Recording of the CSR Pulses Emitted During the Microbunching Instability, using Thin Film YBCO Detectors at UVSOR-III, IPAC2014
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI042  
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WEPRO002 Studies of Ultrashort THz Pulses at DELTA 1936
 
  • P. Ungelenk, L.-G. Böttger, S. Hilbrich, H. Huck, M. Huck, M. Höner, S. Khan, C. Mai, A. Meyer auf der Heide, R. Molo, H. Rast, A. Schick
    DELTA, Dortmund, Germany
  • S. Bielawski, C. Evain, M. Le Parquier, E. Roussel, C. Szwaj
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • N. Hiller, V. Judin, J. Raasch, P. Thoma
    KIT, Karlsruhe, Germany
 
  Funding: Work supported by the DFG, the BMBF, and the state of NRW.
At DELTA, a 1.5-GeV electron storage ring operated as a light source by the Center for Synchrotron Radiation at the TU Dortmund University, coherent ultrashort THz pulses are routinely generated by density-modulated electron bunches. Tracking simulations as well as experimental studies using ultrafast THz detectors and an FT-IR spectrometer aim at understanding the turn-by-turn evolution of the density modulation after an initial laser-electron interaction. Furthermore, intensity-modulated laser pulses are applied to create narrow-band THz radiation. This setup is part of the new short-pulse facility based on coherent harmonic generation.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO002  
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THPME113 Commissioning of an Ultra-fast Data Acquisition System for Coherent Synchrotron Radiation Detection 3497
 
  • C.M. Caselle, M. Brosi, S.A. Chilingaryan, T. Dritschler, E. Hertle, V. Judin, A. Kopmann, A.-S. Müller, J. Raasch, M. Schleicher, M. Siegel, N.J. Smale, J.L. Steinmann, M. Vogelgesang, M. Weber, S. Wuensch
    KIT, Karlsruhe, Germany
 
  The commissioning of a new real-time and high-accuracy data acquisition system suitable for recording individual ultra-short coherent pulses detected by fast terahertz detectors will be presented. The system is able to monitor turn-by-turn all buckets in streaming mode. The main board consists of a direct sampling board operating with a minimum sampling time of 3 psec and a time jitter less than 1.7 psec. The very low noise layout design combined with a wide dynamic range and bandwidth of the analog front-end allows to sample pulse signals generated by various GHz/THz detectors, like NbN and YBCO superconductor film detectors or zero biased Schottky Diode detectors. The digitized data is transmitted to the DAQ system by an FPGA readout board with a data transfer rate of 4 GByte/s. The setup is accomplished by a real-time data processing unit based on high-end graphics processors (GPUs) for on-line analysis of the frequency behaviour of the coherent synchrotron emissions. The system has been successfully used to study the beam properties of the ANKA synchrotron radiation source located at the Karlsruhe Institute of Technology and operating in the energy range between 0.5-2.5 GeV  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME113  
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THPME125 Electrical Field Sensitive High-Tc YBCO Detector for Real-time Observation of CSR 3533
 
  • J. Raasch, K.S. Ilin, Y.-L. Mathis, A.-S. Müller, A. Scheuring, M. Siegel, N.J. Smale, P. Thoma
    KIT, Karlsruhe, Germany
  • S. Bielawski, C. Evain, E. Roussel, C. Szwaj
    PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France
  • B. Holzapfel
    Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
  • M. Hosaka, N. Yamamoto
    Nagoya University, Nagoya, Japan
  • K. Iida
    Leibniz Institute for Solid State and Materials Research Dresden, Dresden, Germany
  • M. Katoh, S.I. Kimura, T. Konomi
    UVSOR, Okazaki, Japan
  • H. Zen
    Kyoto University, Kyoto, Japan
 
  Funding: We thank Agilent Technologies & Tektronix for supplying oscilloscopes. The work was supported by BMBF (05K2010), ANR (2010 blanc 042301), MEXT (Quantum Beam Tech. Prog.), IMS (Int. Collab. Prog.).
High-Tc thin-film YBa2Cu3O7-x (YBCO) detectors were deployed for the real-time observation of Coherent Synchrotron Radiation (CSR). Due to enhanced fabrication techniques enabling the patterning of sub-μm sized detector areas responsivity values as high as 1V/pJ for pulsed THz excitations have been achieved at the ANKA synchrotron facility at the Karlsruhe Institute of Technology (KIT). Response of the detectors is linear over the whole dynamic range of the IR1 beamline. Combining the picosecond scaled response mechanism of the high-temperature superconductor YBa2Cu3O7-x (YBCO) to THz excitations with broad-band readout a temporal resolution of 15 ps full width at half maximum (FWHM) was reached. Real-time resolution of CSR single shots was observed at ANKA and UVSOR-III, the synchrotron facility of the Institute of Molecular Science in Okazaki, Japan.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME125  
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