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Whyte, C.G.

Paper Title Page
TUPCH155 2D and 1D Surface Photonic Band Gap Structures for Accelerator Applications 1388
 
  • I.V. Konoplev, A.W. Cross, W. He, P. MacInnes, A. Phelps, C.W. Robertson, K. Ronald, C.G. Whyte
    USTRAT/SUPA, Glasgow
 
  High frequency (26.5GHz to 40GHz), high power (tens of MW) microwave sources are required for cavity testing and conditioning applications in accelerators such as CLIC. The first study of microwave radiation from a co-axial Free-Electron Maser (FEM) based on a two-mirror cavity formed by a 2D Surface Photonic Band Gap (SPBG) structure (input mirror 10.4cm) and 1D SPBG structure (output mirror 10cm) is presented. The electron beam source consisted of a magnetically insulated plasma flare emission carbon cathode. Application of a 450kV voltage pulse of duration ~250ns across the cathode and grounded anode resulted in the production of a 7.0cm diameter annular electron beam of current ~1500A. The output radiation power from the FEM was measured using a Ka-band horn with 60dB of attenuation in front of a microwave detector located at a distance of 1.5m from the output window. By integrating the microwave power measured at the detector over the radiation pattern a total power of 50 (±10) MW corresponding to an efficiency of ~9% was calculated. The location of the operating frequency was found to lie between 35GHz and 39GHz, which agrees with theoretically predicted frequency of 37.2GHz.  
TUPCH156 Design and Simulation of a Cusp Gun for Gyro-amplifier Application in High Frequency RF Accelerators 1391
 
  • D.H. Rowlands, A.W. Cross, W. He, A. Phelps, E.G. Rafferty, C.W. Robertson, K. Ronald, J. Thomson, C.G. Whyte, A.R. Young
    USTRAT/SUPA, Glasgow
 
  Gyro-amplifiers have potential as the high frequency RF drivers for particle accelerators. They require relativistic electron beams with low velocity spread and with a high fraction of the electron energy associated with the cyclotron motion. For harmonic operation and mode control an axis-encircling beam is desirable. The passage of an electron beam through a non-adiabatic magnetic field reversal (cusp) converts part of the electron beam's axial velocity into axis-encircling transverse velocity. A cusp-based electron beam forming system, yielding a 10MW, 150kV, 70A axis-encircling beam will be presented. This cusp gun is being designed as the electron beam source for a microwave gyro-amplifier that is relevant for high frequency accelerator applications. The latest results from numerical simulations and experiments will be presented and compared.