Author: Floettmann, K.    [Flöttmann, K.]
Paper Title Page
MOPAB255 Demonstration of a Novel Longitudinal Phase Space Linearization Method without Higher Harmonics 805
 
  • R. Stark
    University of Hamburg, Hamburg, Germany
  • K. Flöttmann, M. Hachmann
    DESY, Hamburg, Germany
  • F.J. Grüner
    Center for Free-Electron Laser Science, Universität Hamburg, Hamburg, Germany
  • B. Zeitler
    CFEL, Hamburg, Germany
 
  Nonlinear correlations in the longitudinal phase space of electron bunches can be a decisive limitation to the achievable bunch length compression and attainability of small energy spreads. To overcome the restrictions imposed by nonlinear distortions, the longitudinal phase space distribution must be linearized. Previously, a novel linearization procedure based on the controlled expansion of the bunch between two radio frequency cavities operated at the same fundamental frequency has been presented in *. A demonstration of this linearization method is presented in this work.
*B. Zeitler, K. Floettmann, and F. Grüner, "Linearization of the longitudinal phase space without higher harmonic field," Phys. Rev. ST Accel. Beams, vol. 18, p. 120102, 2015.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB255  
About • paper received ※ 18 May 2021       paper accepted ※ 02 June 2021       issue date ※ 16 August 2021  
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TUPAB026 Application of Plasma Lenses as Optical Matching Device for Positron Sources at Linear Colliders 1394
 
  • M. Formela, N. Hamann, G.A. Moortgat-Pick
    University of Hamburg, Hamburg, Germany
  • K. Flöttmann, G.A. Moortgat-Pick
    DESY, Hamburg, Germany
  • S. Riemann
    DESY Zeuthen, Zeuthen, Germany
 
  Funding: Quantum Universe
In the baseline design of the International Linear Collider (ILC) an undulator-based positron source is foreseen. The proposed luminosity of the recently chosen first energy stage with {s}=250 GeV requires an improvement by a factor of 2500 to the world’s first linear collider, the past SLC experiment. This ambitious luminosity goal can only be achieved, if all technological boundaries are being pushed. One such area is the captured positron number, which is primarily determined in the capture section within the positron source and specifically by its optical matching device. It is responsible for transforming the phase-space of the outgoing particles produced in the target for the succeeding accelerator sections. The plasma lens is a new candidate for this task. It being an especially adequate method due its magnetic field being azimuthal. Optimizing an idealised tapered active plasma lens for the ILC led us to a design with improved captured positron yield, outperforming ILC’s currently proposed quarter wave transformer by approximately 50%. The captured yield also proved to be stable within ±1.5% for deviations in design parameters of ±10%.
 
poster icon Poster TUPAB026 [0.293 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB026  
About • paper received ※ 20 May 2021       paper accepted ※ 24 June 2021       issue date ※ 24 August 2021  
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TUPAB269 Transverse Impedance of Lossy Circular Metal-Dielectric Waveguides 2093
 
  • M. Ivanyan, L.V. Aslyan
    CANDLE SRI, Yerevan, Armenia
  • K. Flöttmann, F. Lemery
    DESY, Hamburg, Germany
 
  The properties of the transverse impedance of a dielectric-loaded metallic circular waveguide are investigated taking into account losses in the outer metallic pipe and in the inner dielectric layer. The dispersion relations, impedances, and wake functions for dipole modes are analyzed and compared for thin and thick dielectric layer cases. The correspondence of the resonant frequencies of the longitudinal monopole and transverse dipole impedances is established.  
poster icon Poster TUPAB269 [0.906 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB269  
About • paper received ※ 16 May 2021       paper accepted ※ 28 May 2021       issue date ※ 10 August 2021  
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