Author: Kazakov, S.
Paper Title Page
TUP066 Three-cell Traveling-wave Superconducting Test Structure 940
 
  • P.V. Avrakhov, A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S. Kazakov, N. Solyak, G. Wu, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Use of a superconducting traveling wave accelerating (STWA) structure* with a small phase advance per cell rather than a standing wave structure may provide a significant increase of the accelerating gradient in the ILC linac. For the same surface electric and magnetic fields the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing wave cavities. The STWA allows also longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed, manufactured and successfully tested** demonstrating the possibility of a proper processing to achieve a high accelerating gradient. These results open the way to take the next step of the TW SC cavity development: to build and test a traveling-wave three-cell cavity with a feedback waveguide. The latest results of the single-cell cavity tests are discussed as well as the design of the test 3-cell TW cavity.
* P. Avrakhov, et al, Phys. of Part. and Nucl. Let, 2008, Vol. 5, No. 7, p. 597
** G. Wu, et al, IPAC 2010, THPD048
 
 
TUP072 High Power Couplers for Project X Linac 952
 
  • S. Kazakov, M.S. Champion, M. Kramp, Y. Orlov, O. Pronitchev, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Project X, a multi-megawatt proton sources is under development in Fermi National Accelerator Laboratory. The key element of the project is a superconducting (SC) 3GV CW proton liner accelerator (linac). The linac includes 5 types of SC accelerating cavities of three 325 and 650 MHz frequencies. The cavities consumes up to 30 kW average RF power and need proper main couplers. Requirements and approach to the coupler design are discussed in the report. New cost effective schemes of the couplers are described. Results of electrodynamics and thermal simulations are presented.  
 
TUP073 Development of an L-band Ferroelectric Phase Shifter 955
 
  • S. Kazakov, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT, USA
  • A. Kanareykin, E. Nenasheva
    Euclid TechLabs, LLC, Solon, Ohio, USA
  • S.V. Shchelkunov
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
 
  Effective operation of the RF cavities in the superconducting accelerators demands fast, high-power RF vector modulators. Recent progress in development of the new materials, ferroelectrics, having tunable dielectric constant and acceptable losses [*] gives the possibility development of such devises. In previous papers [**-***] the authors described different L-band ferroelectric phase shifter designs . At low RF level high operation speed of 2 degree/nsec was demonstrated in waveguide phase shifter. However, the experiments show that a special technology is to be developed that provides a good electric contact between ceramics and the metallic wall. In present paper a new design of the fast high–power ferroelectric phase shifter is described based on the simple ferroelectric elements.
* A. Kanareykin, et al, IPAC 2010, p. 3987
** S. Kazakov, et al, “Fast Ferroelectric Phase Shifter Design For ERLs,” 45th ICFA Beam Dynamics Workshop, 2009
*** S. Kazakov, et al, PAC2007, p. 599.
 
 
TUP075 Cavity Loss Factors of Non-relativistic Beams for Project X 961
 
  • A. Lunin, S. Kazakov, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  Cavity loss factor calculation is an important part of total cryolosses estimation for the super conductive (SC) accelerating structures. There are two approaches how to calculate cavity loss factors, the integration of a wake potential over the bunch profile and the combining of loss factors for individual cavity modes. We applied both methods in order to get reliable results for non-relativistic beam. The time domain CST solver was used for a wake potential calculation and the frequency domain HFSS code was used for the cavity eigenmodes spectrum findings. Finally we present the results of cavity loss factors simulations for a non-relativistic part of the ProjectX and analyze it for various beam parameters.  
 
WEP221 CW Room-Temperature Bunching Cavity for the Project X MEBT 1900
 
  • G.V. Romanov, S. Barbanotti, E. Borissov, J.A. Coghill, I.G. Gonin, S. Kazakov, N. Solyak, V.P. Yakovlev
    Fermilab, Batavia, USA
 
  The Project-X, a multi-MW proton source based on superconducting linac, is under development at Fermilab. The front end of the linac contains a CW room temperature MEBT section which comprises ion source, RFQ and high-bandwidth bunch selective chopper. The length of the chopper exceeds 10 m, so four re-bunching cavities are used to support the beam longitudinal dynamics. The RF and mechanical designs of the re-bunching cavity including stress and thermal analysis are reported.  
 
MOP144 Multi-Harmonic Cavity for RF Breakdown Studies 361
 
  • Y. Jiang
    Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
  • J.L. Hirshfield
    Yale University, Physics Department, New Haven, CT, USA
  • S. Kazakov, S.V. Kuzikov
    Omega-P, Inc., New Haven, Connecticut, USA
 
  Funding: DOE, Office of HEP
An axially-asymmetric cavity to support several modes at harmonically-related frequencies is predicted to sustain higher RF breakdown thresholds than a conventional pillbox cavity, when driven by two or more external RF phase-locked harmonic sources. Experimental efforts are underway at Yale Beam Physics Lab to study RF breakdown in a bimodal asymmetric cavity. Such a cavity could be a basic building-block for a future high-gradient warm accelerator structure.
* S.Yu. Kazakov, S.V. Kuzikov, Y. Jiang, and J.L. Hirshfield, PRSTAB, 13, 071303 (2010).
** S.V. Kuzikov, S.Yu. Kazakov, Y. Jiang, and J.L. Hirshfield, PRL 104, 214801 (2010).