Author: Sekutowicz, J.K.
Paper Title Page
MOPFAV001
Overview of CW R&D With a European XFEL Cryomodule  
 
  • A. Bellandi, J. Branlard, J. Eschke, Ç. Gümüş, D. Kostin, R. Onken, J.K. Sekutowicz, E. Vogel
    DESY, Hamburg, Germany
 
  Since 2011 a research and development program is carried out at DESY to study the feasibility of a possible Continuous-Wave (CW) upgrade of the European X-ray Free Electron Laser (XFEL). Cryo-Module Test Bench (CMTB) is a test facility at DESY used to perform tests with accelerating modules equipped with TESLA-type superconducting cavities. In this proceeding, the most recent tests at CMTB on module XM50.1 are presented. For the European XFEL upgrade, a key-importance question to answer is the cryomodules’ heat load when driven in CW. Therefore, tests at accelerating gradients up to 19 MV/m per cavity at 2K were carried to determine the cavities’ dissipated power. Operating at QLs > 107 is also challenging for the LLRF: the narrow RF bandwidths involved require active online detuning disturbances rejection techniques. Therefore a new detuning estimator was developed. The estimator is also capable of working as a quench/multipacting detector. Tests on XM50.1 show that it is possible to estimate detuning disturbances with a sub-hertz precision and to catch multipacting events. Finally, the maximum achieved gradients with the module and after RF conditioning are presented.  
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TUPTEV006 Development and Adustment of Tools for Superconducting RF Gun Cavities 495
 
  • B. van der Horst, D. Klinke, A. Muhs, M. Schmökel, J.K. Sekutowicz, S. Sievers, N. Steinhau-Kühl, A. Sulimov, J.H. Thie, L. Trelle, E. Vogel
    DESY, Hamburg, Germany
 
  For the superconducting radio frequency (SRF) 1.6-cell gun cavities (CV) developed at DESY, a similar fabrication and treatment process, as for the European XFEL 9-cell cavities is foreseen. The different length and geometry of these cavities lead to a number of adjustments to existing and the development of new tools. This paper covers the new designs and adaptations of a tuning tool, chemistry flanges, a wall thickness measurement device, as well as a new high-pressure rinsing spray head and an optical inspection camera for the 1.6-cell 1.3 GHz DESY SRF gun cavities under the development for the European XFEL.  
poster icon Poster TUPTEV006 [1.397 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPTEV006  
About • Received ※ 21 June 2021 — Revised ※ 05 August 2021 — Accepted ※ 18 September 2021 — Issue date ※ 18 November 2021
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WEPFDV006 Activities at NCBJ Towards Development of the Future, Fully-Superconducting, XFEL-Type, RF Electron Gun 566
 
  • J. Lorkiewicz, P.J. Czuma, A.M. Kosińska, P. Krawczyk, R.M. Mirowski, R. Nietubyć, M. Staszczak, K. Szamota-Leandersson
    NCBJ, Świerk/Otwock, Poland
  • J.K. Sekutowicz
    DESY, Hamburg, Germany
 
  Our group at NCBJ works on upgrade of 1.6-cell, SRF, XFEL-type injector in collaboration with DESY and other laboratories. The work is focused on preparation of lead-on-niobium photocathode, its positioning in the gun cavity and on the UV laser system for photocurrent excitation. RF focusing effect was used to minimize the predicted emittance and transverse size of accelerated e- beam. Following beam dynamics computation, it has been proposed that the photocathode be recessed 0.45 mm into the rear wall of the gun cavity. It helps focusing e- beam in its low-energy part. Preparation of sc cathodes of Pb layer on Nb plugs (*, **) is reported, aimed at reaching clean, planar and uniform Pb films. The laser system will consist of commercially available Pharos laser and a 4-th harmonic generator. A gaussian, 300 fs long, 257 nm in wavelength UV pulse will be transformed in time by a pulse stretcher/stacker and in space by pi-shaper. The planned optical system will generate cylindrical photoelectron bunch 2 - 30 ps long and 0.2 - 3 mm wide.
* J. Lorkiewicz et al., Vacuum 179 (2020) 109524
** R. Nietubyc et al., NIM A891 (2018) pp. 78-86
 
poster icon Poster WEPFDV006 [2.014 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPFDV006  
About • Received ※ 21 June 2021 — Accepted ※ 13 April 2022 — Issue date; ※ 03 May 2022  
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