Keyword: gun
Paper Title Other Keywords Page
TUPTEV001 RF Experience from 6 Years of ELBE SRF-Gun II Operation cavity, cathode, SRF, operation 477
 
  • A. Arnold, P.N. Lu, S. Ma, P. Murcek, A.A. Ryzhov, J. Schaber, J. Teichert, H. Vennekate, R. Xiang
    HZDR, Dresden, Germany
  • G. Ciovati, P. Kneisel
    JLab, Newport News, Virginia, USA
 
  At the electron accelerator for beams with high brilliance and low emittance (ELBE), the second version of a superconducting radio-frequency (SRF) photoinjector was brought into operation in 2014. After a period of commissioning, a gradual transfer to routine operation took place in 2017 and 2018, so that more than 3000h of user beam have already been generated since 2019. During this time, a total of 20 cathodes (2 Cu, 12 Mg, 6 Cs2Te) were used, but no serious cavity degradation was observed. In this paper, we summarize the operational experience of the last 6 years of SRF gun operation, with special emphasis on the main RF properties of the cavity. This includes the evolution of QvsE, dark current, multipacting, but also mechanical properties such as Lorentz force detuning, helium pressure sensitivity as well as microphonics. The latter is closely connected to an active compensation by a so-called low-level RF feedback loop, which is also briefly presented.  
poster icon Poster TUPTEV001 [2.143 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPTEV001  
About • Received ※ 21 June 2021 — Revised ※ 25 December 2021 — Accepted ※ 22 February 2022 — Issue date ※ 16 April 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPTEV006 Development and Adustment of Tools for Superconducting RF Gun Cavities cavity, SRF, FEL, cathode 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPFDV006 Activities at NCBJ Towards Development of the Future, Fully-Superconducting, XFEL-Type, RF Electron Gun cathode, electron, cavity, plasma 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  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPCAV015 Refurbishment and Testing of the WiFEL E-Gun at Argonne cavity, FEL, electron, SRF 627
 
  • T.B. Petersen, G. Chen, M.V. Fisher, M. Kedzie, M.P. Kelly, T. Reid
    ANL, Lemont, Illinois, USA
  • P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
 
  We report on the refurbishment and testing of the Wisconsin Free Electron Laser (WiFEL) superconducting radiofrequency electron gun with application as an electron injector for DOE accelerators and as a possible future stand-alone tool for electron microscopy. Initial testing at ANL showed the cavity had a very low quality factor, ~107, later determined to be due to contamination some-time since the initial assembly. Following ultrasonic cleaning, high-pressure water rinsing, reassembly, and cold testing, the e-gun has largely recovered with Q~109 and surface electric fields ~15 MV/m. We intend that WiFEL be available as a testbed for future high brightness sources and, in particular, for testing an SRF gun photocathode loader design; an essential, and as yet, not sufficiently proven technology. We report here on many operationally important properties of a quarter-wave SRF cavity for application as an e-gun, including microphonics, pressure sensitivity, and mechanical tuning. New electromagnetic simulations show that the WiFEL cavity shape and design can be optimized in several respects.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPCAV015  
About • Received ※ 21 June 2021 — Revised ※ 23 October 2021 — Accepted ※ 07 April 2022 — Issue date ※ 07 April 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPTEV003 A Superconducting Magnetic Shield for SRF Modules with Strong Magnetic Field Sources solenoid, SRF, niobium, shielding 637
 
  • J. Völker, A. Frahm, S. Keckert, J. Knobloch, A.N. Matveenko, A. Neumann, H. Plötz, Y. Tamashevich
    HZB, Berlin, Germany
  • J. Knobloch
    University of Siegen, Siegen, Germany
 
  Frequently SRF modules require strong focusing magnets close to SRF cavities. The shielding of those magnetic fields to avoid flux trapping, for example during a quench, is a challenge. At HZB, the bERLinPro photo-injector module includes a 1.4 cell SRF cavity placed in close proximity to a superconducting (SC) focusing solenoid. At full solenoid operation, parts of the double mu-metal shield are expected to saturate. To prevent saturation, we developed a new superconducting Meissner-Shield. Several tests of different designs were performed both in the injector module and in the HoBiCaT test facility. The measured results of the final design show a significant shielding that are in good agreement with calculations. Based on these results, a reduction of the magnetic flux density in the mu-metal shields of almost one order of magnitude is expected The design has now been incorporated in the injector module. In this paper we will present the design, the setup and results of the final testing of the superconducting shield.  
poster icon Poster WEPTEV003 [1.854 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPTEV003  
About • Received ※ 21 June 2021 — Revised ※ 16 August 2021 — Accepted ※ 21 August 2021 — Issue date ※ 15 March 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)