Author: Cheban, S.
Paper Title Page
WEPML002 Design of 650 MHz Tuner for PIP-II Project 2671
 
  • Y.M. Pischalnikov, S. Cheban, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Proton Improvement Plan (PIP) II project at Fermilab is a proton driver linac which will use of five different cavity geometries including a 650 MHz 5-cell elliptical cavities that will operate in RF-pulse mode. Detuning of these cavities by Lorentz Forces will be large and strongly depend of the stiffness of the cavity's tuner. First prototype tuner built and tested warm [1,2]. Measured stiffness of the prototype tuner was below 30kN/mm instead of expected from simulation 70kN/mm [2]. Significant effort has been invested into understanding discrepancy between simulation and experimental data that led to newest tuner design. Updated 'dressed cavity-helium vessel-tuner' model provided consistent results between ANSYS simulations and experiment results. Modified tuner design and analysis in limitations for overall 'cavity/tuner system' stiffness will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML002  
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WEPML006 Modified Slow Tuner Design for Cavity 1 Inside LCLS II Cryomodules 2684
 
  • Y.M. Pischalnikov, T.T. Arkan, S. Cheban, J.P. Holzbauer, J.A. Kaluzny, Y.O. Orlov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
Initial LCLS-II cryomodule testing at Fermilab showed microphonics on the furthest upstream cavity (number 1) at least factor 2 larger than on the rest of the cavities. Testing indicated that this was a difference in the mechanical support of cavity 1, not a local acoustic source. Further investigation pointed to the upstream beam-pipe of the cavity 1. The upstream cavity flange has a solid spool piece connection to the beamline gate valve unlike the other cavities, which all connect through bellows. The gate valve's weight is supported by sliding system (free in z-axis) connected to large diameter Helium gas return pipe. The tuner design was modified to transform interface between cavity#1 and gate valve. Arms of the tuner for cavity 1 were extended and became the support structure for gate valve, eliminating the connection to the helium return pipe. Modification of the tuner design and results in microphonics mitigations will be presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML006  
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WEPML009 Superconducting Magnet Performance in LCLS-II Cryomodules 2693
 
  • V.S. Kashikhin, S. Cheban, J. DiMarco, E.R. Harms, A.V. Makarov, T. Strauss, M.A. Tartaglia
    Fermilab, Batavia, Illinois, USA
 
  Abstract' New LCLS-II Linear Superconducting Accelerator Cryomodules under construction at Fermilab. Inside each SCRF Cryomodule installed superconducting magnet package to focus and steer an electron beam. The magnet package has the iron dominated configuration with racetrack type quadrupole and dipole conductively cooled coils. For easier installation the magnet could be split in the vertical plane. Initially the magnet was tested in a liquid helium bath, and were performed high precision magnetic field measurements. Several Cryomodules with magnets inside were built and successfully tested at Fermilab test facility. In the paper presented Cryomodule magnet packages test results, discussed the magnet, and current leads conduction cooling performance.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML009  
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WEPML019 Design Update of the SSR1 Cryomodule for PIP-II Project 2721
 
  • V. Roger, S. Cheban, T.H. Nicol, Y.O. Orlov, D. Passarelli, P. Vecchiolla
    Fermilab, Batavia, Illinois, USA
 
  This paper reports the design update of the Single Spoke Resonator 1 (SSR1) cryomodule developed in the framework of PIP-II project at Fermilab. The most re-cent design changes and results of calculations per-formed to optimize the vacuum vessel, current leads, piping system and thermal shield are described. Then the estimated heat loads of the cryomodule leading to the sizing of the cryogenic valves will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML019  
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THPAL034 Dynamic Tuner Development for Medium β Superconducting Elliptical Cavities 3709
SUSPL090   use link to see paper's listing under its alternate paper code  
 
  • C. Contreras-Martinez, P.N. Ostroumov
    FRIB, East Lansing, USA
  • E. Borissov, S. Cheban, Y.M. Pischalnikov, V.P. Yakovlev, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  Funding: Work supported by U.S. DOE SCGSR program under contract number DE-SC0014664, Michigan State University, and Fermi Research Alliance under contract N. DEAC02-07CH11959 with the U.S. DOE
The Facility for Rare Isotope Beams (FRIB) is developing a 5-cell 644 MHz βopt=0.65 elliptical cavity for a future linac energy upgrade to 400 MeV/u for the heaviest uranium ions. Superconducting elliptical cavities operated in continuous wave, such as the ones for FRIB, are prone to microphonics which can excite mechanical modes of the cavities. It has been shown that the detuning due to microphonics can be mitigated with the use of piezo actuators (fast tuner) as opposed to the costly option of increasing the input RF power. The FRIB slow/fast dynamic tuner will be based on the Fermilab experience with similar tuners like those developed for the linac coherent light source (LCLS) II and proton improvement plan (PIP) II. This paper will present the results of tuner properties on the bench.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAL034  
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