| Paper |
Title |
Page |
| THP006 |
Performance of a Digital LLRF Field Control System for the J-PARC Linac
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574 |
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- S. Michizono, S. Anami, Z. Fang, S. Yamaguchi
KEK, Ibaraki
- T. Kobayashi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- H. Suzuki
JAEA, Ibaraki-ken
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Twenty high power klystrons are installed in the J-PARC linac. The requirements for the rf field stabilities are ±1% in amplitude and ±1 deg. in phase during a 500 us flat-top. In order to satisfy these requirements, we adopt the digital feedback and feed-forward system with FPGAs and a commercial DSP board. The FPGAs (Virtex-II 2000) enable a fast PI control for a vector sum of two cavity fields. The measured stability during rf pulse was ±0.15% in amplitude and ±0.15 deg in phase. The tuner control was successively operated by a way of the DSP board by measuring the phase difference between the cavity input wave and the cavity field. Beam loading effects were emulated using a beam-loading test box. By proper feed-forward, the rf stability was less than ±0.3% and ±.15 deg.
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| THP009 |
Performance of RF Reference Distribution System for the J-PARC Linac
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583 |
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- T. Kobayashi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Anami, S. Michizono, S. Yamaguchi
KEK, Ibaraki
- E. Chishiro
JAEA, Ibaraki-ken
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Installation of the J-PARC linac machines (Phase I) has been almost completed and the beam commissioning will be started in December this year. The error of the accelerating field must be within ±1 degree in phase and ±1% in amplitude. Thus, high phase stability is required as an RF reference. Our objective concerning the phase stability of the reference aims at less than ±0.3 degrees. Last year the installation of the RF reference distribution system was completed. The reference signal is optically distributed to all of the low-level RF control systems by using E/O, O/E, Optical Amplifier and Optical Couplers and so on. The performance of this system was evaluated. The phase stability of ±0.06 degrees was obtained.
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| THP010 |
Low-level RF system for STF
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586 |
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- T. Matsumoto, S. Fukuda, H. Katagiri, S. Michizono, Y. Yano
KEK, Ibaraki
- Z. Geng
IHEP Beijing, Beijing
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The Super-conducting RF Test Facility (STF) has been constructed to establish the production technique of a cavity having a high gradient and operated for the high power testing of the klystron and couplers being installed in the superconducting cavities. An accelerating electric field stability of 0.3% (rms) in amplitude and 0.3 degree (rms) in phase is also required for the RF system in STF. In order to satisfy these requirements, a digital LLRF control system using FPGA is adopted, and the components required for the digital LLRF system have been developed.
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| THP022 |
Status of RF Sources in Super-Conducting RF Test Facility (STF) at KEK
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613 |
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- S. Fukuda, M. Akemoto, H. Hayano, H. Katagiri, S. Kazakov, S. Matsumoto, T. Matsumoto, S. Michizono, H. Nakajima, K. Nakao, T. Shidara, T. Takenaka, Y. Yano, M. Yoshida
KEK, Ibaraki
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Super-conducting rf test facility (STF) has been progessing in KEK since 2005. In this paper, we describe the current status of rf sources in STF. STF rf sources comprise of a long pulse modulator with bouncer circuit, a pulse transformer, an L-band 5MW klystron, power distribution system and low level rf system. We have completed the construction of the first rf system and have been testing for the system evaluation and for the coupler test of the super-conducting cavity. We have a schedule to feed a power to the cryomodule with 8 super-conducting cavities in December of 2006. We also describe the plan of the second rf sources of STF.
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