Keyword: quadrupole
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MOPB03 High-Energy Scraper System for the S-DALINAC Extraction Beam Line - Commissioning Run experiment, linac, extraction, dipole 75
 
  • L.E. Jürgensen, M. Arnold, T. Bahlo, C. Burandt, R. Grewe, J. Pforr, N. Pietralla, A. Rost, S. Weih, J. Wissmann
    TU Darmstadt, Darmstadt, Germany
  • F. Hug
    IKP, Mainz, Germany
  • T. Kürzeder
    HIM, Mainz, Germany
 
  Funding: Funded by Deutsche Forschungsgemeinschaft under grant No. GRK 2128
The S-DALINAC is a thrice recirculating, superconducting linear electron accelerator at TU Darmstadt. It delivers electron beams in cw-mode with energies up to 130 MeV. The high-energy scraper system has been installed in its extraction beam line to reduce the energy spread and improve the energy stability of the beam for the experiments operated downstream. It comprises three scraper slits within a dispersion-conserving chicane consisting of four dipole magnets and eight quadrupole magnets. The primary scraper, located in a dispersive section, allows to improve and stabilize the energy spread. In addition energy fluctuations can be detected. Scraping of x- and y-halo is implemented in two positions enclosing the position of the primary scraper. We will present technical details and results of the first commissioning run of the recently installed system at the S DALINAC. Besides improving on the energy spread, it proved to be a valuable device to observe energy spread and energy fluctuations as well as to reduce background count rates next to the experimental areas.
 
poster icon Poster MOPB03 [2.824 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPB03  
About • paper received ※ 05 September 2018       paper accepted ※ 11 September 2018       issue date ※ 29 January 2019  
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MOPB10 A Study on the Influence of Bunch Longitudinal Distribution on the Cavity Bunch Length Measurement cavity, electron, FEL, flattop 97
 
  • Q. Wang, Q. Luo, B.G. Sun, F.F. Wu
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  Funding: Supported by National Key R&D Program of China (2016YFA0401900, 2016YFA0401903), NSFC (11375178, 11575181) and the Fundamental Research Funds for the Central Universities (WK2310000046)
Cavity bunch length measurement is used to obtain the bunch length depending on the eigenmodes exciting in-side the cavity. For today’s FELs, the longitudinal distribution of particles in electron bunch (bunch shape) may be non-Gaussian, sometimes very novel. In this paper, the influence of bunch shape on the cavity bunch length measurement is analyzed, and some examples are given to verify the theoretical results. The analysis shows that the longitudinal distribution of particles in electron bunch has little influence on the cavity bunch length measure-ment when the bunch length is less than 1 ps and the eigenmodes used in measurement are below 10GHz.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-MOPB10  
About • paper received ※ 09 September 2018       paper accepted ※ 10 September 2018       issue date ※ 29 January 2019  
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TUPC12 Beam Transverse Quadrupole Oscillation Measurement in the Injection Stage for the HLS-II Storage Ring storage-ring, injection, betatron, electron 325
 
  • F.F. Wu, F.L. Gao, L.T. Huang, X.Y. Liu, P. Lu, B.G. Sun, J.G. Wang, J.H. Wei, T.Y. Zhou
    USTC/NSRL, Hefei, Anhui, People’s Republic of China
 
  Funding: Supported by the National Science Foundation of China (Grant No. 11705203, 11575181, 11605202) and the National Key Research and Development Program of China(No. 2016YFA0402000)
Beam transverse quadrupole oscillation can be excited in the injection stage if injected beam parameters(twiss parameters or dispersion) are not matched with the parameters in the injection point of the storage ring. In order to measure the beam transverse quadrupole oscillation in the injection stage for the HLS-II storage ring, some axially symmetric stripline BPMs were designed. Transverse quadrupole component for these BPMs was simulated and off-line calibrated. Beam transverse quadrupole oscillation has been measured when beam was injected into the HLS-II electron storage ring. The spectrum of the transverse quadrupole component showed that beam transverse quadrupole oscillation is very obvious in the injection stage and this oscillation isn’t the second harmonic of beam betatron oscillation. The relationship between transverse quadrupole oscillation and beam current was also analyzed and the result shows that the relationship is not linear.
 
poster icon Poster TUPC12 [0.467 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-TUPC12  
About • paper received ※ 06 September 2018       paper accepted ※ 12 September 2018       issue date ※ 29 January 2019  
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WEPA17 Development, Fabrication and Laboratory Tests of Bunch Shape Monitors for ESS Linac electron, dipole, target, space-charge 407
 
  • S.A. Gavrilov, D.A. Chermoshentsev, A. Feschenko
    RAS/INR, Moscow, Russia
 
  Two Bunch Shape Monitors have been developed and fabricated in INR RAS for European Spallation Source linac. To fulfil the requirements of a 4 ps phase resolution the symmetric λ-type RF-deflector based on the parallel wire line with capacitive plates has been selected. Additional steering magnet to correct incline of the focused electron beam is also used. Limitations due to space charge of the analysed beam and due to external magnetic fields are discussed. The results of the laboratory tests of the monitors are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IBIC2018-WEPA17  
About • paper received ※ 04 September 2018       paper accepted ※ 11 September 2018       issue date ※ 29 January 2019  
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