Author: Glöckner, F.
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MOPTEV013 The VSR Demo Module Design – A Spaceframe-Based Module for Cavities with Warm Waveguide HOM Absorbers 233
  • F. Glöckner, D. Böhlick, M. Bürger, V. Dürr, A. Frahm, J. Knobloch, F. Pflocksch, A.V. Vélez, D. Wolk, N.W. Wunderer
    HZB, Berlin, Germany
  The VSR (Variable pulse length Storage Ring) demo module is a prototype for the superconducting upgrade of HZB’s Bessy II. The module houses two 1.5 GHz superconducting cavities operated at 1.8 K in continuous wave (CW) mode. Each cavity has five water cooled Waveguide HOM Absorbers with high thermal load (450 W), which requires them to be water cooled. This setup introduces several design challenges, concerning space restriction, the interconnection of warm and cold parts and the alignment. In order to provide support and steady alignment an innovative space frame was designed. The transition from cold to warm over the partially superconducting waveguides made a more complex design for shielding and cooling system necessary. With the design close to completion, we are now entering the purchase phase.  
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DOI • reference for this paper ※  
About • Received ※ 21 June 2021 — Revised ※ 02 September 2021 — Accepted ※ 18 November 2021 — Issue date ※ 02 December 2021
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WEPTEV008 VSR Demo Cold String: Recent Developments and Manufacturing Status 647
  • N.W. Wunderer, V. Dürr, A. Frahm, H.-W. Glock, F. Glöckner, J. Knobloch, E. Sharples-Milne, A.V. Tsakanian, A.V. Vélez
    HZB, Berlin, Germany
  • M. Bonezzi, A. D’Ambros, R. Paparella
    INFN/LASA, Segrate (MI), Italy
  • J. Guo, J. Henry, R.A. Rimmer
    JLab, Newport News, Virginia, USA
  • J. Knobloch
    University of Siegen, Siegen, Germany
  • A.V. Vélez
    Technical University Dortmund, Dortmund, Germany
  The BESSY VSR project aims to demonstrate the possibility to simultaneously run both long (15ps) and short bunches (1.7ps) within BESSY II storage ring. To achieve this, a new SRF cavity system with higher harmonic cavities (3 and 3.5 harm.) needs to be installed. The combined cavity SRF beating allows for stable bunch shortening for half of the buckets while standard lengths remaining for the other half. These SRF cavities will be equipped with waveguide-connected HOM absorbers and will be controlled with a blade tuner plus piezos. To demonstrate the feasibility of this complex system the VSR DEMO cold string consists of two 1.5 GHz cavities, each featuring five waveguides and a higher power coupler, plus all interconnecting elements coupled to the beam vacuum. For most of these components the fundamental development work is completed and has been reported in the past. This paper summarizes recent enhancements, component detailing and manufacturing status. The key cold string components such as cavities, higher power couplers and blade tuners have already entered the manufacturing phase. All other cold string components will be ready for purchase at the latest beginning of 2022.  
DOI • reference for this paper ※  
About • Received ※ 18 June 2021 — Revised ※ 09 August 2021 — Accepted ※ 22 November 2021 — Issue date ※ 05 January 2022
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