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CT10 |
Beam Diagnostics in the AGOR Cyclotron
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80 |
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- S. Brandenburg, W.K. van Asselt, H. Post, H.W. Schreuder
KVI, Kernfysisch Versneller Instituut, Groningen, The Netherlands
- B. Launé
IPN, Institut de Physique Nucléaire, Orsay, France
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The beam diagnostics equipment in modern multi-particle, multi-energy
cyclotrons for research in nuclear physics is reviewed, using the
superconducting cyclotron AGOR at the KVI as an example. An extensive set
of diagnostics tools has been integrated already in the design stage. It
includes three scanning probes for beam centering, a scanning probe
for the measurement of radial and vertical beam oscillations and
beamlosses, beam phase pick-ups to optimize isochronism of the magnetic
field and profile and current measurements along the beam path through
the four movable extraction elements. The operating experience gained
since the start-up of the cyclotron in 1996 is discussed for the various
diagnostics tools and improvements are described.
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PT12 |
Beam Phase Measurements in the AGOR Cyclotron
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193 |
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- S. Brandenburg, H.W. Nijboer, W.K. van Asselt
KVI, Kernfysisch Versneller Instituut, Groningen, The Netherlands
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Beamphase measurement to optimize the isochronism is an essential part of
the diagnostics in multi-particle, multi-energy cyclotrons. In the AGOR
cyclotron an array of 13 nondestructive beamphase pick-ups is installed.
To reduce the large disturbances from the RF-system the measurements are
traditionally performed at the 2nd harmonic of the RF-frequency. To
further improve the sensitivity intensity modulation of the beam has been
introduced. This creates side-bands in the Fourier spectrum, that are
completely free of interference from the RF-system. These side-bands
contain information on both the beamphase with respect to the
accelerating voltage and the number of revolutions up to the radius of
the measurement. A specific case is intensity modulation at the orbital
frequency, where the side-bands contain only information on the
beamphase. Measurements with the different methods will be presented,
demonstrating that the intensity modulation strongly improves the
sensitivity of the measurement. Useful beamphase measurements can now be
made for beam intensities down to 10 nA.
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