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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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| TUPCH059 |
Dual-mode Beam Current Monitor
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1145 |
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- S. Ninomiya, T. Adachi, S. Fukumoto
KEK, Ibaraki
- S.H. Hatori, T. Kurita
WERC, Tsuruga , Fukui
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A new type HEREWARD-transformer is developed. The original scheme connects pickup coil to the low impedance input of the amplifier to increase the time constant of the transformer. The new scheme employs negative impedance circuit which realizes perfect cancellation of the coil resistance. Therefore DC component of the beam current can be observed. Since number of winding of the pick up coil is only 100-turns, therefore by using the original scheme with a fast operational amplifier, the transformer can be operated at fast CT mode. Thus the dual mode operation can be realized by single core; the first mode is the slow beam intensity monitor, and the second is a fast response transformer. This operation mode realizes an accurate observation of the beam injection process. In order to make installation easy, the core is divided into two pieces. The magnetic shield from bending field is also installed. This monitor is developed at KEK, and installed into the accelerator at the WAKASA WAN Energy Research Center.
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| WEPCH186 |
Present Status of FFAG Accelerators in KURRI for ADS Study
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2367 |
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- M. Tanigaki, M. Inoue, K. Mishima, S. Shiroya
KURRI, Osaka
- S. Fukumoto, Y. Ishi
Mitsubishi Electric Corp, Energy & Public Infrastructure Systems Center, Kobe
- S. Machida
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
- Y. Mori
KEK, Ibaraki
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KART (Kumatori Accelerator driven Reactor Test) project is in progress at the Kyoto University Research Reactor Institute (KURRI) since fiscal year 2002. We are now constructing a 150 MeV proton FFAG accelerator complex as a neutron production driver for this project. The whole of this FFAG complex is expected to be in the test operation around the spring in 2006. The developments and the current status of this accelerator complex, including the current status of this project, will be presented.
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| TUPLS114 |
An Improvement of Matching Circuit of RF Kicker Electrodes
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1771 |
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- T. Kurita, S. Fukumoto, S.H. Hatori
WERC, Tsuruga , Fukui
- S. Ninomiya
KEK, Ibaraki
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Beam extraction system at accelerator of The Wakasa Wan Energy Research Center employs RF knockout technology. Narrow band RF noise is applied to the transverse kicker electrodes to increase betatron amplitude of the beam. Recently some improvements of the beam extraction system are introduced: To improve the shape of the spill, a feedback control of noise amplitude is introduced. The feedback control system works as an attenuator, therefore it is necessary to enhance the noise amplitude of the kicker electrodes to obtain agreeable effect on the spill shape. In order to obtain a higher voltage, we revamp the matching circuit at the electrodes. By introducing the resonating characteristic at the matching circuit, we obtained 3 times more amplitude at the electrodes. General shape of the spill is improved by this work, and extraction efficiency at a real operating condition is also improved.
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