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Conradie, J. L.

Paper Title Page
TUPC020 Development of Non-destructive Beam Current Measurement for the iThemba LABS Cyclotrons 1089
 
  • Z. Kormány
    ATOMKI, Debrecen
  • J. L. Conradie, J. L.G. Delsink, D. T. Fourie, J. V. Pilcher, P. F. Rohwer
    iThemba LABS, Somerset West
  • K. Juhasz
    University of Debrecen, Debrecen
 
  The 200 MeV separated-sector cyclotron and its two 8 MeV solid-pole injector cyclotrons at iThemba LABS deliver beams of light and heavy ions, as well as polarized protons, with variable energy for nuclear physics research, a low-intensity proton 200 MeV beam for proton therapy and a high-intensity 66 MeV proton beam for neutron therapy and the production of radioisotopes. The intensity of the 66 MeV proton beam has recently been increased to 250 μA. This necessitated development of non-destructive beam diagnostic equipment, amongst others, for beam current measurement at various positions in the different beamlines. It was decided to determine the beam current by digitizing and analyzing the signals from capacitive phase probes on-line, instead of using more costly DC beam-current transformers. It was also important to design the phase probes with as low as possible inductance in their support to the diagnostic vacuum chambers to eliminate ringing in the probe signals. The design of the probes, the analyses of the probe signals and the results that were obtained with the equipment will be presented.  
TUPC022 Non-destructive Beam Position and Profile Measurements Using Light Emitted by Residual Gas in a Cyclotron Beam Line 1095
 
  • J. Dietrich
    FZJ, Jülich
  • C. Boehme
    UniDo/IBS, Dortmund
  • A. H. Botha, J. L. Conradie, M. A. Crombie, J. H. Du Toit, D. T. Fourie, H. W. Mostert, P. F. Rohwer, P. A. van Schalkwyk
    iThemba LABS, Somerset West
  • T. Weis
    DELTA, Dortmund
 
  Non-destructive beam position and profile measurements were made in the transfer beam line between an 8 MeV solid-pole injector cyclotron and a 200 MeV separated-sector cyclotron that is used for nuclear physics research, radioisotope production and proton and neutron therapy. Light emitted from the beam induced ionization of residual gas particles was measured using a multi-cathode photomultiplier tube (PMT). The PMT was mounted outside the vacuum system on a diagnostic chamber and light passing through a glas window was focused on the photocathode array by means of a lens. The anode currents of the PMT were measured with computer-controlled electronic equipment recently developed for measuring the currents of multi-wire beam profile monitors. Software was developed to control the measurement processes, remove offset values and further process the data digitally. The measured beam positions and profiles were compared with those determined with a multi-wire beam profile monitor for a 3.14 MeV proton beam. It was necessary to shield the PMT from gamma rays generated on nearby slits. The design of the measuring equipment is discussed and the results of the measurements are presented.