Paper |
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MOPC105 |
Activities of Hitachi Relating to Construction of J-PARC Accelerator
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310 |
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- Y. Chida, S. Koseki
Hitachi Ltd., Ibaraki-ken
- M. Abe
Hitachi, Ltd., Power & Industrial Systems R&D Laboratory, Ibaraki-ken
- K. Nakamura, M. Watanabe, T. Watanabe, T. Watanuki
Hitachi. Ltd., Hitachi Works, Hitachi-shi
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The Japan Proton Accelerator Research Complex (J-PARC) consists of a 330-m-long linac, a 3-GeV rapid cycle synchrotron with a circumference of 350 m, and a 50-GeV synchrotron with a circumference of 1,570 m. Owing to a collaboration between the Japan Atomic Energy Agency (JAEA) and the High Energy Accelerator Research Organization (KEK), the accelerators will be commencing operations at the site of JAEA Tokai Research and Development Center. The beam commissioning of the entire accelerator system is planned to take place before the end of 2008. Along with the JAEA and KEK, Hitachi has contributed to the construction of the system by manufacturing some major equipment with specifications that are of the highest level in the world.
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WEPC138 |
Transient Electromagnetic Analysis and Thermal Design on the Magnet of 3-GeV Synchrotron
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2332 |
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- M. Abe, S. Tounos
Hitachi, Ltd., Power & Industrial Systems R&D Laboratory, Ibaraki-ken
- T. Adachi
KEK, Ibaraki
- Y. Chida
Hitachi Ltd., Ibaraki-ken
- K. Nakamura, T. Watanabe
Hitachi. Ltd., Hitachi Works, Hitachi-shi
- T. Takayanagi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- N. Tani
JAEA/LINAC, Ibaraki-ken
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J-PARC 3GeV synchrotron is operated at 25Hz alternatively, which can generate eddy currents and heat. They can disturb continuous operations. We prepared a design technique to analyze them and manage the temperature rises of the magnets. Eddy current and hysteresis heat generations were calculated with 3D models then temperature rises were evaluated with natural convection cooling from surfaces. The technique was applied on the dipole, quadrupole and bump magnets. Slits on intense eddy current position can decrease the heat generation, however deep slits can disturb magnetic field distribution. Their depth and positions were optimized for the temperature rise reduction. So far, the synchrotron operation is fair with reasonable temperature rises.
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TUPC052 |
Beam Phase and RF Fields Monitoring System Using Lock-In Amplifier for RIBF
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1173 |
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- R. Koyama, M. K. Fujimaki, N. Fukunishi, M. Hemmi, O. Kamigaito, M. Kase, Y. Kotaka, N. S. Sakamoto, K. Suda, T. Watanabe, K. Yamada, Y. Yano
RIKEN, Saitama
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The accelerator complex of the RIKEN RI Beam Factory (RIBF) consists of two injectors - heavy ion linac (RILAC and CSM) and K78 MeV AVF cyclotron - and four cyclotrons from the upstream, RRC (K540 MeV), fRC (K570 MeV), IRC (K980 MeV), and SRC (K2600 MeV). In such a multi-stage acceleration system, one of the most important factors for stable operation is to maintain the matching of beam-phases between accelerators. However, drifts of beam-phases have been frequently observed, reasons of which might be the fluctuation of RF-fields, variation of magnetic field, and so on. Hence, it is important to monitor beam-phases constantly, and we have developed a monitoring system using the commercial RF lock-in amplifier model SR844 manufactured by Stanford Research Systems. In addition, the system for monitoring the RF-fields has also been developed to investigate its stability and the correlation with beam-phases. The beam-phases at eleven phase probes installed in the beam transport lines and RF-fields of 25 cavities are monitored in a uranium acceleration. In addition, lock-in amplifiers are also used to obtain good isochronous magnetic fields of three cyclotrons in the RIBF.
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TUPC001 |
Optics Calculation and Emittance Measurement toward Automatic Beam Tuning of Linac
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1035 |
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- T. Asaka, H. Dewa, H. Hanaki, T. Kobayashi, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida
JASRI/SPring-8, Hyogo-ken
- T. Watanabe
SES, Hyogo-pref.
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The SPring-8 1-GeV linac has a total of 13 sets of 80MW klystron units. In usual operation, two klystron units are driven as the standby unit. If there's any problem with an arbitrary klystron unit, the beam operation is able to restart immediately by using the standby unit. In that case, the optimization of beam optics has carried out using beam screen monitors. This beam tuning spend about one hour. In order to reduce the beam tuning time, we are promoting the development of the automatic beam optics tuning system. Since the complete understanding of the beam envelope is important, the particles tracking simulation of the linac was carried out by using PARMELA and SAD. Five sets of beam size monitors were installed in the end of the linac for measurement of the real beam envelope. In a beam study applying the simulation results, the beam waist was actually formed at the 10-m long drift space after the 1-GeV chicane section as predicted by SAD. The values of the measured beam emittance were smaller than the simulation results.
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