| Paper |
Title |
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| TUPCH130 |
Development of the Feed-forward System for Beam Loading Compensation in the J-PARC RCS
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1319 |
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- F. Tamura, M. Nomura, A. Schnase, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii
KEK, Ibaraki
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In the J-PARC Rapid Cycling Synchrotron (RCS), the heavy beam loading effects due to the high intensity proton beam must be compensated for stable acceleration. The beam feedforward technique is used to compensate the beam loading in the RCS. We present the development of the feedforward system. We designed and built the full-digital system with modern FPGAs to realize high accuracy, stability and predictability of the compensation. Because of the low Q value of each accelerating cavity, the wake voltage consists of not only the accelerating harmonic component but also higher harmonics. Thus, the system is designed to compensate the beam loading at several harmonics. The system has two parts. In the first part, vector components of the selected harmonic are detected from the beam signal picked up by a wall current monitor. The compensation RF signal is generated from the vector components with proper gain and phase in the latter part. The gain and phase are set individually for each harmonic and each cavity of the twelve cavities. We also present the preliminary test results of the newly developed modules.
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| TUPCH131 |
High Power Test of MA Cavity for J-PARC RCS
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1322 |
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- M. Yamamoto, M. Nomura, A. Schnase, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Toda, M. Yoshii
KEK, Ibaraki
- K. Hasegawa
JAEA, Ibaraki-ken
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We have been constructing the RF system for the J-PARC RCS. Almost all of the power supplies and the tube amplifiers have been constructed, and the cavities are under construction. All of them are tested at the experimental hall before installing into the J-PARC RCS building. We test the hybrid cavity scheme to realize the optimum cavity Q-value. The results of the test are described.
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| TUPCH193 |
Low Level RF Control System Modules for J-PARC RCS
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1465 |
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- A. Schnase, M. Nomura, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Anami, E. Ezura, K. Hara, C. Ohmori, A. Takagi, M. Yoshii
KEK, Ibaraki
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After completing the design phase, the VME modules for the Low Level RF Control (LLRF) of the Rapid Cycling Synchrotron of J-PARC are now in the production and debugging phase. First all modules are tested for basic functionality, for example dual harmonic signal generation. Then sets of modules are connected together to check higher-level functions and feedback. Finally, the LLRF modules are interfaced to high voltage components like amplifiers and cavities. We present the results of these tests, the test methods and test functions on several levels. This way we simulate beam operation working conditions and gain experience in controlling all parameters.
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| TUPCH128 |
New Cutting Scheme of Magnetic Alloy Cores for J-PARC Synchrotrons
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1313 |
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- C. Ohmori, S. Anami, E. Ezura, Y. Funahashi, K. Hara, K. Hasegawa, A. Takagi, M. Toda, K. Ueno, M. Yoshii
KEK, Ibaraki
- Y. Morita, T. Yoshioka
ICEPP, Tokyo
- M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
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A new cutting method using a grindstone was developed to manufacture the magnetic alloy cores. The problem of local temperature rise around the cut surfaces was solved. Long-term high-power tests have been performed for both J-PARC RCS and MR RF systems. Mechanism of local heating, new cutting scheme, and manufacturing method are presented.
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