Paper |
Title |
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MOPCH118 |
Wideband Low-output-impedance RF System for the Second Harmonic Cavity in the ISIS Synchrotron
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321 |
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- Y. Irie
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- D. Bayley, G.M. Cross, I.S.K. Gardner, M.G. Glover, D. Jenkins, A. Morris, A. Seville, S.P. Stoneham, J.W.G. Thomason, T. Western
CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
- J.C. Dooling, D. Horan, R. Kustom, M.E. Middendorf, G. Pile
ANL, Argonne, Illinois
- S. Fukumoto, M. Muto, T. Oki, A. Takagi, S. Takano
KEK, Ibaraki
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Wideband low-output-impedance RF system for the second harmonic cavity in the ISIS synchrotron has been developed by the collaboration between Argonne National Laboratory, US, KEK, Japan and Rutherford Appleton Laboratory, UK. Low output impedance is realized by the feedback from plate output to grid input of the final triode amplifier, resulting in less than 30 ohms over the frequency range of 2.7 - 6.2 MHz which is required for the second harmonic cavity. The vacuum tubes in the driver and final stages are both operated in class A, and a grid bias switching system is used on each tube to avoid unnecessary plate dissipations during a non-acceleration cycle. High power test was performed with a ferrite-loaded second harmonic cavity, where the bias current was swept at 50 Hz repetition rate. The maximum voltage of 12kV peak per accelerating gap was obtained stably at earlier period of an acceleration cycle. A beam test with this system is planned at the ISIS synchrotron in order to investigate how the low impedance system works under heavy beam loading conditions, and is capable of mitigating the space charge detuning at the RF trapping stage.
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WEPLS119 |
Power Converters for the ISIS Second Target Station Project (TS-2)
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2655 |
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- S.L. Birch, A. Morris, S.P. Stoneham
CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
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The Extract Proton Beamline to the ISIS second target station will require magnets to be powered by ac/dc power converters. A total of 50 magnets, quadrupole and dipole, require high stability dc current converters over a large dynamic range from several kW to 600kW. There is also a requirement for two 10Hz pulsed magnets to extract the proton beam from the present 50Hz target beamline, and hence specially designed power supplies are necessary. This paper describes the selection process, types of topology considerations and final selections.
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