Author: Solyak, N.
Paper Title Page
MOPLR006 Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure 142
 
  • A. Lunin, T.N. Khabiboulline, N. Solyak
    Fermilab, Batavia, Illinois, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR006  
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MOPLR007 Redesign of the End Group in the 3.9 GHz LCLS-II Cavity 145
 
  • A. Lunin, I.V. Gonin, T.N. Khabiboulline, N. Solyak
    Fermilab, Batavia, Illinois, USA
 
  Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the U.S. DOE
Development and production of Linac Coherent Light Source II (LCLS-II) is underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SCRF) electron linac. The 3.9 GHz third harmonic cavity similar to the XFEL design will be used in LCLS-II for linearizing the longitudinal beam profile*. The initial design of the 3.9 GHz cavity developed for XFEL project has a large, 40 mm, beam pipe aperture for better higher-order mode (HOM) damping. It is resulted in dipole HOMs with frequencies nearby the operating mode, which causes difficulties with HOM coupler notch filter tuning. The CW linac operation requires an extra caution in the design of the HOM coupler in order to prevent its possible overheating. In this paper we present the modified 3.9 GHz cavity End Group for meeting the LCLS-II requirements
* LCLS-II 3.9 GHz Cryomodules, Physics Requirements Document, LCLSII-4.1-PR-0097-R1, SLAC, USA, 2015
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR007  
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MOPLR008 Status Of the ILC Main Linac Design 149
 
  • A. Saini, V.V. Kapin, N. Solyak
    Fermilab, Batavia, Illinois, USA
 
  International Linear collider (ILC) is a proposed accelerator facility which is primarily based on two 11-km long superconducting main linacs. In this paper we present recent updates on the main linac design and discuss changes made in order to meet specification outlined in the technical design report (TDR).  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR008  
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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  
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MOPLR022 Commissioning and First Results from the Fermilab Cryomodule Test Stand 185
 
  • E.R. Harms, M.H. Awida, C.M. Baffes, K. Carlson, S.K. Chandrasekaran, B.E. Chase, E. Cullerton, J.P. Edelen, J. Einstein, C.M. Ginsburg, A. Grassellino, B.J. Hansen, J.P. Holzbauer, S. Kazakov, T.N. Khabiboulline, M.J. Kucera, J.R. Leibfritz, A. Lunin, D. McDowell, M.W. McGee, D.J. Nicklaus, D.F. Orris, J.P. Ozelis, J.F. Patrick, T.B. Petersen, Y.M. Pischalnikov, P.S. Prieto, O.V. Prokofiev, J. Reid, W. Schappert, D.A. Sergatskov, N. Solyak, R.P. Stanek, D. Sun, M.J. White, C. Worel, G. Wu
    Fermilab, Batavia, Illinois, USA
 
  Funding: Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.
A new test stand dedicated to SRF cryomodule testing, CMTS1, has been commissioned and is now in operation at Fermilab. The first device to be cooled down and powered in this facility is the prototype 1.3 GHz cryomodule assembled at Fermilab for LCLS-II. We describe the demonstrated capabilities of CMTS1, report on steps taken during commissioning, provide an overview of first test results, and survey future plans.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPLR022  
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MOP106018 Measurement of the Transverse Beam Dynamics in a TESLA-type Superconducting Cavity 323
SPWR025   use link to see paper's listing under its alternate paper code  
 
  • A. Halavanau, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • N. Eddy, D.R. Edstrom, A. Lunin, P. Piot, J. Ruan, N. Solyak
    Fermilab, Batavia, Illinois, USA
 
  Funding: US Department of Energy (DOE) under contract DE-SC0011831 with Northern Illinois University. Fermilab is operated by the Fermi Research Alliance LLC under US DOE contract DE-AC02-07CH11359.
Superconducting linacs are capable of producing intense, ultra-stable, high-quality electron beams that have widespread applications in Science and Industry. Many project are based on the 1.3-GHz TESLA-type superconducting cavity. In this paper we provide an update on a recent experiment aimed at measuring the transfer matrix of a TESLA cavity at the Fermilab Accelerator Science and Technology (FAST) facility. The results are discussed and compared with analytical and numerical simulations.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOP106018  
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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  
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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  
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THPLR007 Dark Current Studies in ILC Main Linac 855
 
  • A.I. Sukhanov, I.L. Rakhno, N. Solyak, I.S. Tropin
    Fermilab, Batavia, Illinois, USA
 
  Studies and optimization of design of the International Linear Collider (ILC) based on the TESLA-type 9-cell 1.3 GHz superconducting RF (SRF) cavities are currently underway. Dark current electron generated by field emission (FE) in SRF cavities can be captured and accelerated in the main ILC linac up to very high energy before they are removed by focusing and steering magnets. Dark current electrons, interacting with the materials surrounding SRF cavities, produce electromagnetic showers and contribute to the radiation in the main ILC tunnel. In this paper present preliminary results of the simulation study of dark current in the ILC linac.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THPLR007  
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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.
 
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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  
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