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| TUPPP01 |
DEE Voltage Calibration for the ACCEL Proton Therapy Cyclotron
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cyclotron, electron, proton, vacuum |
102 |
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- J. H. Timmer, P. A. Komorowski, H. Röcken
ACCEL, Bergisch Gladbach
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ACCEL Instruments GmbH has developed a superconducting cyclotron for the use in proton therapy systems. An essential step during the commissioning of the medical cyclotron is the calibration and balancing of the DEE voltages. Using a very compact and low cost X-ray detector the bremsstrahlung spectrum of stray electrons accelerated by the four RF cavities has been measured. To determine the peak voltage a regression analysis of the measured spectrum has been carried out using a non-linear multiple convolution model taking into account the energy gain of the stray electrons between the liner and the DEE, the bremsstrahlung spectrum integrated over angle as well as the attenuation effects caused by the liner and the limited detector resolution. The correlation between the model and the measurement was very good. A software tool enabling automatic spectrum acquisition and analysis capable of online determination of the DEE voltages has been developed in LabVIEW graphical programming environment. Careful balancing of the DEE voltages resulted in better beam focusing and a cyclotron extraction efficiency larger than 80%. The absolute acceleration voltage has been confirmed by turn-separation measurements.
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| WEA4IS02 |
Numerical Computation of Kicker Impedances: Towards a Complete Database for the GSI SIS100/300 Kickers
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kicker, impedance, coupling, simulation |
277 |
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- B. Doliwa, T. Weiland
TEMF, Darmstadt
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Funding: Work supported by the GSI and the DFG under contract GK 410/3.
Fast kicker modules represent a potential source of beam instabilities in the planned Facility for Antiproton and Ion Research (FAIR) at the Gesellschaft für Schwerionenforschung (GSI), Darmstadt. Containing approximately six tons of lossy ferrite material, the more than forty kicker modules to be installed in the SIS-100 and SIS-300 synchrotrons are expected to have a considerable parasitic influence on the high-current beam dynamics. In order to be able to take these effects into account in the kicker design, a dedicated electromagnetic field software for the calculation of coupling impedances has been developed. Here we present our numerical results on the longitudinal and transverse kicker coupling impedances for the planned components and point out ways of optimization. Besides the inductive coupling of the beam to the external network -relevant below 100 MHz- particular attention is paid to the impact of ferrite losses up to the beam-pipe cutoff frequency.
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Slides
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