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Fourie, D.T.

Paper Title Page
TUPCH077 Beam Phase Measurement in a 200 MeV Cyclotron 1187
 
  • J.L. Conradie, A.H. Botha, P.J. Celliers, J.L.G. Delsink, D.T. Fourie, P.T. Mansfield, P.F. Rohwer, M.J. Van Niekerk
    iThemba LABS, Somerset West
  • J. Dietrich, I. Mohos
    FZJ, Jülich
 
  New phase measuring equipment is being planned for the K 200 variable frequency, separated-sector cyclotron at iThemba LABS near Cape Town. A commercial lock-in amplifier is used to measure the beam phase over the full radial range. Measurements are made at the third and fifth harmonics of the main RF frequency to limit pick-up from the flat-topping and main dees. Computer-generated signals, with phase and amplitude control, at the same harmonics, are used to cancel the signals coupled from the dees to the phase probes. In addition the signals without beam are vectorially subtracted from those with beam to enhance the sensitivity and accuracy. Results of measurements, using these techniques, on existing phase probes in the cyclotron, will be presented.