Author: Yakovlev, V.P.
Paper Title Page
MOPLR015 Thermal-Mechanical Study of 3.9 GHz CW Coupler and Cavity for LCLS-II Project 171
 
  • I.V. Gonin, E.R. Harms, T.N. Khabiboulline, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Third harmonic system was originally developed by Fermilab for FLASH facility at DESY and then was adopted and modified by INFN for the XFEL project [1-3]. In contrast to XFEL project, all cryomodules in LCLS-II project will operate in CW regime with higher RF average power for 1.3 GHz and 3.9 GHz cavities and couplers. Design of the cavity and fundamental power coupler has been modified to satisfy LCLS-II requirements. In this paper we discuss the results of COMSOL thermal and mechanical analysis of the 3.9 GHz coupler and cavity to verify proposed modifica-tion of the design. For the dressed cavity we present simulations of Lorentz force detuning, helium pressure sensitivity df/dP and major mechanical resonances.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR015  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOP106021 Superconducting Traveling Wave Cavity Tuning Studies 327
 
  • R.A. Kostin
    LETI, Saint-Petersburg, Russia
  • P.V. Avrakhov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by US DOE SBIR # DE-SC0006300
Superconducting traveling wave cavity (SCTW) can provide 1.2-1.4 times larger accelerating gradient than conventional standing wave SRF cavities [1]. Firstly, traveling wave opens the way to use other than Pi-mode phase advance per cell which increase transit time factor. Secondly, traveling wave is not so sensitive to cavity length as standing wave, which length is limited to 1 meter because of field flatness degradation. 3 cell SCTW cavity was proposed [2] and built for high gradient traveling wave demonstration and tuning studies. This paper describes analytical model that was used for cavity development. Tuning properties and requirements are also discussed.
' r.kostin@euclidtechlabs.com
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106021  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPRC014 RF Losses in 1.3 GHz Cryomodule of The LCLS-II Superconducting CW Linac 798
 
  • A. Saini, A. Lunin, N. Solyak, A.I. Sukhanov, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  The Linac Coherent Light Source (LCLS) is an x-ray free electron laser facility. The proposed upgrade of the LCLS facility is based on construction of a new 4 GeV superconducting (SC) linac that will operate in continuous wave (CW) mode. The major infrastructure investments and the operating cost of a SC CW linac are outlined by its cryogenic requirements. Thus, a detail understanding of RF losses in the cryogenic environment is critical for the entire project. In this paper we review RF losses in a 1.3 GHz accelerating cryomodule of the LCLS-II linac. RF losses due to various sources such untrapped higher order modes (HOMs), resonant losses etc. are addressed and presented here.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPRC014  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPLR008 3-Cell Superconducting Traveling Wave Cavity Tuning at Room Temperature 858
 
  • R.A. Kostin
    LETI, Saint-Petersburg, Russia
  • P.V. Avrakhov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • T.N. Khabiboulline, A.M. Rowe, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by US DOE SBIR # DE-SC0006300
A superconducting traveling wave (SCTW) cavity with a feedback waveguide will support a higher average acceleration gradient compared to conventional SRF standing wave cavities [1]. Euclid Techlabs, in collaboration with Fermilab, previously demonstrated a high accelerating gradient in a single cell cavity with a feedback waveguide [2], and the new waveguide design did not limit the cavity performance. The next step is high gradient traveling wave SRF cavity test. A 3-Cell SCTW cavity was designed and developed [3] to demonstrate the SRF traveling wave regime. Two Nb SCTW cavities were built, characterized and cold tested in 2016. This paper presents the results of cavity inspection, field flatness analysis, along with a discussion of the tuning procedure.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR008  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPLR032 Update on SSR2 Cavity EM Design for PIP-II 920
 
  • P. Berrutti, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Proton Improvement Plan II (PIP-II) is the future plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. SC linac using five cavity types. One 162.5 MHz half wave resonator, two 325 MHz spoke resonators and two 650 MHz elliptical 5-cell cavities, provide acceleration to 800 MeV. The EM design of the second family of spoke resonator is presented in this paper. The work reported is a thorough electromagnetic study including: the RF parameters, multipacting mitigation and transverse field asymmetry. The cavity is now ready for structural design analysis.  
poster icon Poster THPLR032 [1.947 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR032  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPLR036 SRF Low-Beta Elliptical Resonator Two-Ring Stiffening 929
 
  • E.N. Zaplatin
    FZJ, Jülich, Germany
  • I.V. Gonin, T.N. Khabiboulline, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  Elliptical SRF cavities are the basic accelerating structures for the high energy part of many accelerators. Since a series of external loads on the resonator walls predetermine the main working conditions of the SC cavities the detailed investigation of their mechanical properties should be conducted in parallel with the main RF design. The effects of very high electromagnetic fields that result in strong Lorentz forces and the pressure on cavity walls from the helium tank that also deforms the cavity shape, the tuning scheme resulting in the change of accelerating field profile and mechanical eigen resonances of cavities which are the main source of the microphonics must be taken into account during integrated design of the resonator and its liquid helium vessel. SRF elliptical cavities for the medium energies (β=v/c is around 0.6) inherently have more flexible shape and their ultimate stiffening with a "standard" stiffening rings installed between resonator cells becomes problematic. The second row of the rings should enhance the overall cavity rigidity. In the paper we report the basic investigations of the cavity two-row ring stiffening using FNAL 650 MHz β=0.61 as an example. The single-cell investigation results were used as the reference to develop the ultimate scheme of the helium vessel structure to ensure the best resonator stability.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR036  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPLR041 650 MHz Elliptical Superconducting RF Cavities for PIP-II Project 943
 
  • I.V. Gonin, E. Borissov, A. Grassellino, C.J. Grimm, V. Jain, S. Kazakov, V.A. Lebedev, A. Lunin, C.S. Mishra, D.V. Mitchell, T.H. Nicol, Y.M. Pischalnikov, G.V. Romanov, A.M. Rowe, N.K. Sharma, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, Illinois, USA
 
  The PIP-II 800 MeV linac employs 650 MHz elliptical 5-cell CW-capable cavities to accelerate up to 2 mA peak beam current of H in the energy range 185 - 800 MeV. The low beta (LB) βG = 0.61 portion should accelerate from 185 MeV-500 MeV using 33 LB dressed cavities in 11 cryomodules. The high beta (HB) βG = 0.92 portion of the linac should accelerate from 500 to 800 MeV using 24 HB dressed cavities in 4 cryomodules. The development of both LB and HB cavities is going on under IIFC collaboration. The development of LB cavity initiated at VECC Kolkatta and HB cavity is going at RRCAT, Indore. This paper present design methodology adopted starting from RF design to get mechanical dimensions of the RF cells and then explains dressing of the cavity for both low beta and high beta cavities. Further the tuner design and its integration to the dressed cavity is discussed. Paper also explains the salient design features of these dressed cavities.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR041  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)