Author: Grau, A.W.
Paper Title Page
TUPAB267 Investigation of Beam Impedance and Heat Load in a High Temperature Superconducting Undulator 2089
 
  • D. Astapovych, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • T.A. Arndt, E. Bründermann, N. Glamann, A.W. Grau, B. Krasch, A.-S. Müller, R. Nast, D. Saez de Jauregui, A. Will
    KIT, Karlsruhe, Germany
 
  The use of high temperature superconducting (HTS) materials can enhance the performance of superconducting undulators (SCU), which can later be implemented in free electron laser facilities, synchrotron storage rings and light sources. In particular, the short period < 10 mm undulators with narrow magnetic gap < 4 mm are relevant. One of the promising approaches considers a 10 cm meander-structured HTS tapes stacked one above the other. Then, the HTS tape is wound on the SCU. The idea of this jointless undulator has been proposed by, and is being further developed at KIT. Since minimizing the different sources of heat load is a critical issue for all SCUs, a detailed analysis of the impedance and heat load is required to meet the cryogenic system design. The dominant heat source is anticipated to be the resistive surface loss, which is one of the subjects of this study. Considering the complexity of the HTS tape, the impedance model includes the geometrical structure of the HTS tapes as well as the anomalous skin effect. The results of the numerical investigation performed by the help of the CST PS solver will be presented and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB267  
About • paper received ※ 18 May 2021       paper accepted ※ 26 July 2021       issue date ※ 12 August 2021  
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TUPAB270 Thermal Transition Design and Beam Heat-load Estimation for the COLDDIAG Refurbishment 2097
 
  • H.J. Cha, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
 
  Funding: This work is supported by the BMBF project 05H18VKRB1 HIRING (Federal Ministry of Education and Research).
The COLDDIAG (cold vacuum chamber for beam heat load diagnostics) developed at Karlsruhe Institute of Technology has been modified for more studies at cryogenic temperatures different from the previous operations at 4 K in a cold bore and at 50 K in a thermal shield. The key components in this campaign are two thermal transitions connecting both ends of the bore at 50 K with the shield at the same or higher temperature. In this paper, we present design efforts for the compact transitions, allowed heat intakes to the cooling power margin and mechanical robustness in the cryogenic environment. A manufacture scheme for the transition and its peripheral is also given. In addition, the beam heat loads in the refurbished COLDDIAG are estimated in terms of the accelerator beam parameters.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB270  
About • paper received ※ 12 May 2021       paper accepted ※ 02 June 2021       issue date ※ 12 August 2021  
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WEPAB135 Progress of the Development of a Superconducting Undulator as a THz Source for FELs 2933
 
  • J. Gethmann, S. Casalbuoni, N. Glamann, A.W. Grau, A.-S. Müller, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  • D. Astapovych, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
  • S. Casalbuoni
    EuXFEL, Schenefeld, Germany
 
  Funding: This work is supported by the BMBF project 05K19VK2 SCUXFEL (Federal Ministry of Education and Research) and by the DFG-funded Doctoral School KSETA: Science and Technology.
To produce radiation in the THz frequency range at X-ray Free Electron Lasers, undulators with large period length, high fields, and large gaps are required. These demands can be fulfilled by superconducting undulators. In this contribution, the actual requirements on the main parameters of such a superconducting undulator will be discussed and the progress of the design will be discussed. In addition, beam impedance and heat load results obtained analytically as well as by large-scale wakefield simulations will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB135  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 31 August 2021  
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THPAB048 Design and Fabrication Concepts of a Compact Undulator with Laser-Structured 2G-HTS Tapes 3851
 
  • A. Will, T.A. Arndt, E. Bründermann, N. Glamann, A.W. Grau, B. Krasch, A.-S. Müller, R. Nast, D. Saez de Jauregui
    KIT, Eggenstein-Leopoldshafen, Germany
  • D. Astapovych, H. De Gersem, E. Gjonaj
    TEMF, TU Darmstadt, Darmstadt, Germany
 
  To produce small-scale high-field undulators for table-top free electron lasers (FELs), compact designs have been proposed using high temperature superconducting (HTS) tapes, which show both large critical current densities and high critical magnetic fields with a total tape thickness of about 50 μm and a width of up to 12 mm. Instead of winding coils, a meander structure can be laser-scribed directly into the superconductor layer, guiding the current path on a quasi-sinusoidal trajectory. Stacking pairs of such scribed tapes allows the generation of the desired sinusoidal magnetic fields above the tape plane, along the tape axis. Two practically feasible designs are presented, which are currently under construction at KIT: A coil concept wound from a single structured tape with a length of 15 m, which is a progression of a design that has been presented already in the past, as well as a novel stacked and soldered design, made from 25 cm long structured tapes, soldered in a zig-zag-pattern. In this contribution the designs are briefly recapped and the experimental progress is presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB048  
About • paper received ※ 19 May 2021       paper accepted ※ 12 July 2021       issue date ※ 15 August 2021  
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THPAB126 Operational Experience and Characterization of a Superconducting Transverse Gradient Undulator for Compact Laser Wakefield Accelerator-Driven FEL 4009
 
  • K. Damminsek, A. Bernhard, J. Gethmann, A.W. Grau, A.-S. Müller, Y. Nie, M.S. Ning, S.C. Richter, R. Rossmanith
    KIT, Karlsruhe, Germany
 
  A 40-period superconducting transverse gradient undulator (TGU) has been designed and fabricated at Karlsruhe Institute of Technology (KIT). Combining a TGU with a Laser Wakefield Accelerator (LWFA) is a potential key for realizing an extremely compact Free Electron Laser (FEL) radiation source. The TGU scheme is a viable option to compensate the challenging properties of the LWFA electron beam in terms of beam divergence and energy spread. In this contribution, we report on the operational experience of this TGU inside its own cryostat and show the current status of the TGU and the further plan for experiments. This work is supported by the BMBF project 05K19VKA PlasmaFEL (Federal Ministry of Education and Research).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB126  
About • paper received ※ 19 May 2021       paper accepted ※ 25 August 2021       issue date ※ 02 September 2021  
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