| Paper |
Title |
Page |
| MOPLT070 |
FFAG as Phase Rotator for the PRISM Project
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713 |
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- A. Sato, M. Aoki, Y. Arimoto, Y. Kuno, M. Yoshida
Osaka University, Osaka
- Y. Iwashita
Kyoto ICR, Uji, Kyoto
- S. Machida, Y. Mori, C. Ohmori, T. Yokoi, K. Yoshimura
KEK, Ibaraki
- S. Ninomiya
RCNP, Osaka
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A Fixed Field Alternating Gradient (FFAG) ring will be used as a phase rotator in the PRISM project. We report a design of the PRISM-FFAG in this paper. PRISM stands for "Phase Rotated Intense Slow Muon beam". It is a project to realize a super muon beam, which combines high-intensity, low-energy, narrow energy-spread and high purity. Its aimed intensity is about 1011-1012 muons per sec. The muon beam will be provided with a low kinetic energy of 20MeV to optimize for the stopped muon experiments. FFAG has some advantageous characteristics to achieve such superb beam. These are a large momentum (longitudinal) acceptance, a wide transverse acceptance with strong focusing, and synchrotron oscillation, which is needed to perform phase rotation. According to simulations, initial energy spread of 20MeV±40% is reduced down to ±6% after 5 turns of muons in the FFAG ring. In the FFAG ring almost all pions decay into muon, hence extracted beam has extremely low pion contamination. A program to construct the PRISM-FFAG ring has been started. It would be completed by the end of JFY 2005.
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| WEPKF046 |
Gradient Field Generation in a Uniform Gapped Magnet
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1705 |
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- Y. Iwashita
Kyoto ICR, Uji, Kyoto
- Y. Arimoto, A. Sato
Osaka University, Osaka
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Magnets with gradient field (indexed magnets) usually have different gap distances with the different entrance positions. This situation will break a uniformity of the effective length. Trim coils, which are usually used in Cyclotron, are not practical to modify a field distribution when a large gradient is required such as FFAG. In order to generate a gradient field in a constant gapped magnet, a novel method with use of inter-pole is devised. This magnet has not only constant gap but also smaller fringing field compared with a conventional one. This technique should widen the recipe to design a magnet with such a complex magnetic field.
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| WEPKF047 |
A Super Strong Adjustable Permanent Magnet for the Final Focus Quadrupole in a Linear Collider
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1708 |
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- T. Mihara, Y. Iwashita
Kyoto ICR, Uji, Kyoto
- E. Antokhin, M. Kumada
NIRS, Chiba-shi
- C.M. Spencer
SLAC, Menlo Park, California
- E. Sugiyama
NEOMAX Co., Ltd., Mishima-gun, Osaka
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A super strong magnet, which utilizes permanent magnet material and saturated iron, is considered as a candidate for the final focus quadrupole in a linear collider beamline. This modified Halbach magnet configuration can have a higher magnetic field gradient than a normal permanent magnet quadrupole (PMQ) or electromagnet. There are some issues to be solved if a PMQ is to be used as a final focus quadrupole: the variation of its strength with temperature and the need for the field strength to be deliberately changed. One can use special temperature compensation material to improve the temperature dependence with just a small decrease in field gradient compared to a magnet without temperature compensation. The required field variability can be obtained by slicing the magnet into pieces along the beamline direction and rotating these slices. Results of performance measurements on the PMQ with variable strength will be reported including the realization of the temperature compensation technique.
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