Author: Schönfeldt, P.
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MOPRO062 Investigating Polarisation and Shape of Beam Microwave Signals at the ANKA Storage Ring 4090
 
  • J. Schwarzkopf, M. Brosi, C. Chang, E. Hertle, V. Judin, B. Kehrer, A.-S. Müller, A.-S. Müller, A.-S. Müller, M. Schuh, M. Schwarz, P. Schönfeldt, P. Schütze, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • F. Caspers
    CERN, Geneva, Switzerland
 
  At the ANKA synchrotron radiation facility measurements in the microwave range (~10 to 12 GHz) employing a LNB (Low Noise Block), which is the receiving part of a Satellite-TV system, have been carried out. Experiments showed that the observed signal depends on the length of the electron bunches. Furthermore the temporal shape of the microwave signal depends on the detector's position along the accelerator. Due the LNB antenna's sensitivity to polarisation it was also possible to measure the polarisation along the several ns long signal, revealing polarised and non-polarised regions. This paper describes the experimental setup and summarises the observations of the systematic studies performed with the LNB system.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO062  
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MOPRO068 Fluctuation of Bunch Length in Bursting CSR: Measurement and Simulation 237
 
  • P. Schönfeldt, A. Borysenko, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, S. Naknaimueang, M. Schuh, M. Schwarz, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  The ANKA electron storage ring of the Karlsruher Institute of Technology (KIT, Germany) is regularly operated in low-alpha mode to produce short bunches for the generation of coherent synchrotron radiation (CSR). This paper evaluates systematic bunch length measurements taken in low-alpha operation of the ANKA storage ring. Above the bursting threshold not only the emission of CSR occurs in bursts, but also a continuous fluctuation of the bunch's length is observed. The measurements were carried out using concurrent multi turn (using a streak camera) as well as single shot (using electro-optical spectral decoding) methods. Furthermore, we compare information obtained on the fluctuation to simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO068  
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WEOBB02 Status of Single-shot EOSD Measurement at ANKA 1909
 
  • N. Hiller, A. Borysenko, E. Hertle, V. Judin, B. Kehrer, S. Marsching, A.-S. Müller, M.J. Nasse, M. Schuh, P. Schönfeldt, N.J. Smale, J.L. Steinmann
    KIT, Karlsruhe, Germany
  • P. Peier, B. Steffen
    DESY, Hamburg, Germany
  • V. Schlott
    PSI, Villigen PSI, Switzerland
 
  Funding: This work is funded by the BMBF contract numbers: 05K10VKC, 05K13VKA.
ANKA is the first storage ring in the world with a near-field single-shot electro-optical (EO) bunch profile monitor. The method of electro-optical spectral decoding (EOSD) uses the Pockels effect to modulate the longitudinal electron bunch profile onto a long, chirped laser pulse passing through an EO crystal. The laser pulse is then analyzed with a single-shot spectrometer and from the spectral modulation, the temporal modulation can be extracted. The setup has a sub-ps resolution (granularity) and can measure down to bunch lengths of 1.5 ps RMS for bunch charges as low as 30 pC. With this setup it is possible to study longitudinal beam dynamics (e. g. microbunching) occurring during ANKA's low-alpha-operation, an operation mode with compressed bunches to generate coherent synchrotron radiation in the THz range. In addition to measuring the longitudinal bunch profile, long-ranging wake-fields trailing the electron bunch can also be studied, revealing bunch-bunch interactions.
 
slides icon Slides WEOBB02 [12.753 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBB02  
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THPME124 Spectral Analysis of Micro-Bunching Instabilities using Fast THz Detectors 3530
 
  • J.L. Steinmann, E. Hertle, N. Hiller, V. Judin, A.-S. Müller, M. Schuh, P. Schönfeldt, P. Schütze
    KIT, Karlsruhe, Germany
  • E. Bründermann
    Ruhr-Universität Bochum, Bochum, Germany
 
  Micro-bunching instabilities occur at synchrotron light sources when the particle density rises due to compression of the electron bunches. They lead to powerful bursts of coherent synchrotron radiation (CSR) in the THz range at the cost of very unstable intensity and spectral properties, highly fluctuating on a millisecond time scale. For interferometry this changing source demands a long averaging time to achieve a reasonably high signal-to-noise ratio or balancing by the use of an additional reference detector. In this study we present measurements taken by a Martin-Puplett-interferometer in the bursting regime with ultra-fast THz-detectors.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME124  
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