Paper |
Title |
Page |
TUPLS107 |
Operation of the Opposite-Field Septum Magnet for the J-PARC Main-Ring Injection
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1750 |
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- I. Sakai, Y. Arakaki, K. Fan, Y. Saito, M. Tomizawa, M. Uota
KEK, Ibaraki
- A.K. Kawasaki, H. Mori, A. Tokuchi
NICHICON, Shiga
- Y. Morigaki, A. Nishikawa
IHI/Yokohama, Kanagawa
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The opposite field septum magnet system has been applied to the injection system of the J-PARC 50-GeV proton synchrotron. The features of the system are a force-free structure, easy pulse excitation and the possibility of a large-aperture, thin-septum structure. The septum magnet has the structure of an inside-vacuum to eliminate the thickness of the vacuum-chamber walls and electric-insulation layer to make the septum thickness as thin as possible. However the magnet cores and return coils are outside of the vacuum to reduce the out-gassing rate of the vacuum system. Finally, the larger beam aperture than the full acceptance of the ring and larger separation angle can be obtained at the septum magnet for low-loss injection. In this paper we will introduce the methods to eliminate the error fields caused by fabrication errors and eddy current with pulse excitation and stability of high current power supply of 50 kA.
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WEPCH028 |
Position Shuffling of the J-PARC Main Ring Magnets
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1984 |
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- M. Tomizawa, K. Fan, S. Igarashi, K. Ishii, H. Kobayashi, A.Y. Molodozhentsev, K. Niki, E. Yanaoka
KEK, Ibaraki
- Y. Irie
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
- S. Machida
CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
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The J-PARC 50GeV main ring has 96 dipole, 216 quadrupole with 11 families and 72 sextupole magnets with 3 families. Magnets installation in the tunnel started last year and will be planed to finish by the end of next fiscal year. Field measurements of all magnets will soon finish by this March. Deviations for BL, B'L, B"L in dipole, quadrupole and sextupole magnets make COD, beta beat and third integer stopband, respectively. They can be reduced by choosing a pair of magnets with similar field deviation and by positioning them so as to cancel each other considering betatron phase (shuffling). In this paper, we will report our shufflling scheme chosen under the given schedule for installation and field measurements and also will show performances expected by the shufflings.
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WEPLS071 |
Design Method for a Large Aperture Opposite-field Septum Magnet
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2544 |
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- K. Fan, Y. Arakaki, I. Sugai
KEK, Ibaraki
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A novel design septum for Japan Proton Accelerator Research Center (J-PARC) delivers high intensity 3GeV proton beam to the 50GeV main ring is presented. The project requires the construction of the large aperture septum to accommodate the large size and high intensity injection beam. As there limitations due to the lattice size and restricted installation space, the septum must provide a large kick angle to the injection beam. Sufficient clearance between the circulating beam and the injection beam is also needed to reduce the beam loss to an acceptable level to avoid the serious radiation problem. To meet these challenging requirements, a large aperture, thin septum, opposite-field septum magnet has been developed. In this paper, we present the detail studies done for the optimization of the magnet, including DC and pulse magnet.
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