| Paper |
Title |
Page |
| MOPC004 |
Dynamics of a High Density Ion-Beam with Electron Cooling in HIMAC Synchrotron
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416 |
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- T. Uesugi, T. Fujisawa, K. Noda, D. Tann
NIRS, Chiba-shi
- Y. Hashimoto
KEK, Ibaraki
- I.N. Meshkov, E. Syresin
JINR, Dubna, Moscow Region
- S. Ninomiya
RCNP, Osaka
- S. Shibuya, H. Uchiyama
AEC, Chiba
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High density circulating-ion beam was obtained with electron-cooling and cool-stacking injection in HIMAC synchrotron. The ion density was saturated at 1.0e9/cm2. Coherent transverse instability was observed when ion- and electron-beam density was high. The dynamics of the cooled ion-beam are described in this report.
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| TPPT005 |
Dual Harmonic Operation with Broadband MA Cavities in J-PARC RCS
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931 |
| |
- M. Yamamoto, M. Nomura, A. Schnase, F. Tamura
JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Yoshii
KEK, Ibaraki
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In the J-PARC RCS RF system, the fundamental rf acceleration voltage and the 2nd higher harmonic one are applied to each cavity. This is possible, because the magnetic alloy loaded cavities have a broadband characteristic and require no resonant frequency tuning. The tube amplifier provides both rf components. We calculate the operation of the tube under the condition of the dual harmonic, the non-pure resistive load and the class AB push-pull mode.
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| ROAC005 |
Present Status of J-PARC Ring RF Systems
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475 |
| |
- M. Yoshii, S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Toda
KEK, Ibaraki
- M. Nomura, A. Schnase, F. Tamura, M. Yamamoto
JAERI, Ibaraki-ken
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The accelerator of the J-PARC complex consists of the 400 MeV (initially 181 MeV) linac, the rapid cycling 3 GeV Synchrotron and the 50 GeV main Synchrotron. To accelerate an ultra-high intense proton beam, the synchrotrons require a high field gradient rf system (~25kV/m). Alleviating space charge effects is a key issue for minimizing beam losses during a cycle. Longitudinal bunch manipulation is also considered as well as acceleration. Magnetic alloy loaded cavities are the most practical choice for the J-PARC. Such system provides high field gradient, and broadband behavior. It is a stable passive system without tuning control. Multi-tone signals can be fed into the same cavity for acceleration and bunch manipulation. However, the harmonics of circulating beam current within the cavity bandwidth must be taken into account. A feed-forward scheme is used for compensating the beam induced voltages. The low level rf system is fully digital to provide precise control. The specification is based on high reliability and reproductivity. The design consideration of the whole rf system will be described and the current status presented.
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| RPAT005 |
Beam Diagnostics for the J-PARC Main Ring Synchrotron
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958 |
| |
- T. Toyama, D.A. Arakawa, Y. Hashimoto, S. Lee, T. Miura, S. Muto
KEK, Ibaraki
- N. Hayashi, J. Kishiro, R. Toyokawa
JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
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Beam diagnostics: beam intensity monitors (DCCT, SCT, FCT, WCM), beam position monitors (ESM), beam loss monitors (proportional chamber, air ion chamber), beam profile monitors (secondary electron emission, gas-sheet) have been designed, tested, and will be installed for the Main Ring synchrotron of J-PARC (Japan Proton Accelerator Research Complex). This paper describes the basic design principle and specification of each monitor, with a stress on how to cope with high power beam (average circulation current of ~12 A) and low beam loss operation (less than 1 W/m except a collimator region). Some results of preliminary performance test using present beams and a radiation source will be reported.
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