Author: Pischalnikov, Y.M.
Paper Title Page
SUPTEV013 Validation of the 650 MHz SRF Cavity Tuner for PIP-II at 2 K 151
 
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  • S.K. Chandrasekaran, S. Cheban, G.V. Eremeev, F. Furuta, T.N. Khabiboulline, Y.M. Pischalnikov, O.V. Prokofiev, A.I. Sukhanov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  The PIP-II linac will include thirty-six β=0.61 and twenty-four β=0.92 650 MHz 5 cell elliptical SRF cavities. Each cavity will be equipped with a tuning system consisting of a double lever slow tuner for coarse frequency tuning and a piezoelectric actuator for fine frequency tuning. One dressed cavity equipped with an SRF tuner has been tested in the horizontal test stand at Fermilab. Results of testing the cavity-tuner system will be presented.  
poster icon Poster SUPTEV013 [0.830 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV013  
About • Received ※ 22 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 26 February 2022 — Issue date ※ 02 May 2022
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SUPTEV014 SRF Cavity Tuners for 3.9 GHz Cryomodules for LCLS-II Project 155
 
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  • T.T. Arkan, T.N. Khabiboulline, Y.M. Pischalnikov, G.V. Romanov, R.P. Stanek, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  Fermilab conducted testing of three 3.9 GHz cryomodules for the LCLS-II project that will operate in continuous wave mode. A fast/fine tuning component was added to the LCLS-II 3.9 GHz tuner design due to the cavity bandwidth of 130 Hz which consists of two encapsulated piezos. Several cavities faced problems with fast-tuner operations after cooldown to 2 K and tuning the cavities to 3.9 GHz in cryomodule 2. All the piezo actuators were in working conditions but the slow tuner ranges required to stretch some of the cavities to the operational 3.9 GHz frequency were too small to deliver the required preload on the piezos. This behavior can be attributed to several factors: setting the initial warm cavity frequency during production too high, pressure tests of the warm cryomodule could have changed cavity frequency; and the small bending and twisting of the cavity-tuner system during the cooldown and warmup of the cavities. A decision was made to inelastically retune the warm cavities to decrease the unrestrained frequency by 200-300 kHz, this was done via the slow tuner. The results for this retuning method of three 3.9GHz cryomodules will be discussed.  
poster icon Poster SUPTEV014 [0.715 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV014  
About • Received ※ 22 June 2021 — Accepted ※ 23 January 2022 — Issue date; ※ 09 April 2022  
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SUPTEV015 Mitigation of Dielectric Heating of Piezoelectric Actuators at Cryogenic Temperatures 159
 
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
  • Y.M. Pischalnikov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
 
  The new generation of low beam intensity superconducting linacs will require high accelerating gradients for new scientific discoveries. The high accelerating gradient cavities in pulsed SRF linacs will experience large (~1000’s of Hz) detuning caused by Lorentz force detuning (LFD). The piezo actuators that will be used to compensate large LFD must operate at a nominal voltage of 120V to 150V to deliver the required stroke to the cavity. In this high voltage range, the piezo is expected to warm up drastically due to its location in an insulating vacuum environment. Overheating of the piezo will significantly decrease the longevity of the actuator. A collaboration between FNAL and Physik Instrumente (PI) developed a novel piezo actuator design that mitigates piezo overheating. The design consists of using a metal foam in contact with the piezoelectric ceramic stack for heat removal. The second solution used lithium niobite as an alternative material. A comparison of the temperature stability will be presented and discussed. This study characterizes the dielectric properties for both materials. The results obtained are in the temperature range of 10 K to 300 K.  
poster icon Poster SUPTEV015 [0.728 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-SUPTEV015  
About • Received ※ 22 June 2021 — Revised ※ 13 August 2021 — Accepted ※ 21 October 2021 — Issue date ※ 09 April 2022
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MOPTEV002 Extended Range SRF Cavity Tuner for LCLS II HE Project 203
 
  • Y.M. Pischalnikov, T.T. Arkan, C.J. Grimm, B.D. Hartsell, J.A. Kaluzny, T.N. Khabiboulline, Y.O. Orlov, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
 
  Funding: This manuscript has been authorized by Fermi Research Alliance LLC under Contract N. DE-AC02-07CH11359 with U.S. Department of Energy.
The off-frequency detune method is being considered to be applied in the LCLS-II-HE superconducting linac to produce multi-energy electron beams for supporting multiple undulator lines simultaneously. To deliver off-frequency operation (OFO) requirements for SRF cavity tuner must be changed. Tuner design modifications and results of the testing eight cavity/tuner system, deployed in verification cryomodule (vCM), will be presented.
 
poster icon Poster MOPTEV002 [0.705 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-MOPTEV002  
About • Received ※ 22 June 2021 — Revised ※ 16 July 2021 — Accepted ※ 19 August 2021 — Issue date ※ 23 September 2021
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TUPCAV013 STC Qualification Tests of PIP-II HB650 Cavities 465
 
  • A.I. Sukhanov, S.K. Chandrasekaran, G.V. Eremeev, F. Furuta, S. Kazakov, T.N. Khabiboulline, T.H. Nicol, Y.M. Pischalnikov, O.V. Prokofiev, V. Roger, G. Wu, V.P. Yakovlev, J.C. Yun
    Fermilab, Batavia, Illinois, USA
  • C. Contreras-Martinez
    FRIB, East Lansing, Michigan, USA
 
  Design of the high beta 650 MHz prototype cryomodule for PIP-II is currently undergoing at Fermilab. The cryomodule includes six 5-cell elliptical SRF cavities with accelerating voltage up to 20 MV and low heat dissipation (Q0 > 3.3 · 10zEhNZeHn). Characterization of performance of fully integrated jacketed cavities with high power coupler and tuner is crucial for the project. Such a characterization of jacketed cavity requires a horizontal test cryostat. The Fermilab Spoke Test Cryostat (STC) has been upgraded to accommodate testing of 650 MHz cavities. Commissioning of upgraded STC has been reported at SRF’19 conference. In this paper we present results of testing of the prototype HB650 cavity in upgraded STC facility. We characterize cavity performance and qualify it for the prototype HB650 cryomodule assembly.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-TUPCAV013  
About • Received ※ 21 June 2021 — Accepted ※ 21 August 2021 — Issue date; ※ 04 October 2021  
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WEPTEV007 Review of the Application Piezoelectric Actuators for SRF Cavity Tuners 642
 
  • Y.M. Pischalnikov
    Fermilab, Batavia, Illinois, USA
 
  Funding: This manuscript has been authorized by Fermi Research Alliance LLC under Contract N. DE-AC02-07CH11359 with U.S. Department of Energy
Large SRF Linacs and HEP experiments require accurate frequency control, which is achieved using cavity tuners typically actuated by the piezoelectric ceramic stacks. The piezoelectric ceramic stacks became ’standard’ components of the SRF cavity tuner and, depending on the application, could be operated in the different environment: in air, at cryogenic temperature, in vacuum, and submerged in liquid helium. Different applications place different requirements on the piezo actuators, but the important parameters, common to all applications, are the lifetime and reliability of the actuators. Several R&D programs targeting the development of reliable piezo actuators are reviewed in this contribution.
 
poster icon Poster WEPTEV007 [1.215 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2021-WEPTEV007  
About • Received ※ 22 June 2021 — Revised ※ 27 August 2021 — Accepted ※ 18 September 2021 — Issue date ※ 22 November 2021
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