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Karmanenko, S.F.

Paper Title Page
TPAE061 Experimental Investigation of an X-Band Tunable Dielectric Accelerating Structure 3529
 
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • W. Gai, J.G. Power
    ANL, Argonne, Illinois
  • S.F. Karmanenko, A. Semenov
    Eltech University, St. Petersburg
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
  • P. Schoessow
    Tech-X, Boulder, Colorado
 
  Funding: U.S. Department of Energy.

Experimental study of a new scheme to tune the resonant frequency for dielectric based accelerating structure (driven either by the wakefield of a beam or an external rf source) is underway. The structure consists of a single layer of conventional dielectric surrounded by a very thin layer of ferroelectric material situated on the outside. Carefully designed electrodes are attached to a thin layer of ferroelectric material. A DC bias can be applied to the electrodes to change the permittivity of the ferroelectric layer and therefore, the dielectric overall resonant frequency can be tuned. In this paper, we present the test results for an 11.424 GHz rectangular DLA prototype structure that the ferroelectric material's dielectric constant of 500 and show that a frequency tuning range of 2% can be achieved. If successful, this scheme would compensate for structure errors caused by ceramic waveguide machining tolerances and dielectric constant heterogeneity.

 
WPAT095 Low-Loss Ferroelectric for Accelerator Application 4305
 
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  • A. Dedyk, S.F. Karmanenko
    Eltech University, St. Petersburg
  • E. Nenasheva
    Ceramics Ltd., St. Petersburg
  • V.P. Yakovlev
    Omega-P, Inc., New Haven, Connecticut
 
  Funding: U.S. Department of Energy.

Ferroelectric ceramics have an electric field-dependent dielectric permittivity that can be altered by applying a bias voltage. Ferroelectrics have unique intrinsic properties that makes them attractive for high-energy accelerator applications: very small response time of ~ 10-11 sec, considerably high breakdown limit of more than 100 kV/cm, good vacuum properties. Because of these features, bulk ferroelectrics may be used as active elements of tunable accelerator structures,* or in fast, electrically - controlled switches and phase shifters in pulse compressors or power distribution circuits of future linear colliders.** One of the most critical requirements for ferroelectric ceramic in these applications is the dielectric loss factor. In this paper, the new bulk ferroelectric ceramic is presented. The new composition shows a loss tangent of 4× 10-3 at 35 GHz. The ceramics have high tunability factor: the bias voltage of 50 kV/cm was enough to reduce the permittivity from 500 to 400. The material chemical compound, features of the technology process, and mechanical and electrical properties are discussed. The ways of BST ferrolectric parameters further improvement are discussed as well.

*A. Kanareykin, W. Gai, J. Power, E. Sheinman, and A. Altmark, AIP Conf. Proc. 647, Melville, N.Y., 2002, p. 565. **V.P. Yakovlev, O.A. Nezhevenko, J.L. Hirshfield, and A.D. Kanareykin, AIP Conf. Proc. 691, Melville, N.Y., 2003, p.187.