| Paper | Title | Page |
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| MOPCH137 | An Anti-symmetric Lattice for High Intensity Rapid-cycling Synchrotrons | 369 |
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| Rapid cycling synchrotrons are used in many high power facilities like spallation neutron sources and proton drivers. In such accelerators, beam collimation plays a crucial role in reducing the uncontrolled beam loss. Furthermore, the injection and extraction section needs to reside in dispersion-free region to avoid couplings; a significant amount of drift space is needed to house the RF accelerating cavities; orbit, tune, and chromatic corrections are needed; long, uninterrupted straights are desired to ease injection tuning and to raise collimation efficiency. Finally, the machine circumference needs to be small to reduce construction costs. In this paper, we present a lattice designed to satisfy these needs. The lattice contains a drift created by a missing dipole near the peak dispersion to facilitate longitudinal collimation. The compact FODO arc allows easy orbit, tune, coupling, and chromatic correction. The doublet straight provides long uninterrupted straights. The four-fold lattice symmetry separates injection, extraction, and collimation to different straights. This lattice is chosen for the Beijing Spallation Neutron Source synchrotron. | ||
| TUPLS024 | FFAGs as Muon Accelerators for a Neutrino Factory | 1541 |
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| The FFAG accelerator is a solution for rapid acceleration of muons because of its large aperture and no need of magnet ramping. Its particle dynamics is, however, peculiar due to high energy gain per turn and large transverse amplitude, which has not been seen in other types of circular accelerators. One variation of FFAG, called non-scaling FFAG, employs quite new scheme, namely, out of bucket acceleration. We studied emittance distortion, coupled motions among 3-D planes, effects of resonance lines, etc., based on a newly developed tracking code. In this paper, we will emphasize new regime of particle dynamics as well as a modeling technique of FFAG. | ||
| WEPCH028 | Position Shuffling of the J-PARC Main Ring Magnets | 1984 |
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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. | ||
| WEPCH029 | Injection and Extraction Orbit of the J-PARC Main Ring | 1987 |
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| The J-PARC main ring (MR) accelerates a high intensity proton beam and deliver to the neutrino experimental hall by the fast extraction and to the hadron experimental facility by the slow extraction. The beam from the rapid cycle synchrotron (RCS) is injected by the bunch to bucket transfer into the MR. The MR has two beam dump lines, the first one is used to dump the beam at injection energy and the second one can be used to abort accelerated beam. The beam loss at the injection and extraction is one of the critical issue for high intensity proton accelerators. We report designed injection and extraction orbits and discuss about the beam apertures and the beam loss. | ||
| WEPCH079 | Effects of Intrinsic Nonlinear Fields in the J-PARC RCS | 2104 |
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| In order to accelerate a high intense proton beam with small particle losses, the J-PARC RCS, which is being constructed at JAEA, has a large acceptance. In such synchrotrons, the nonlinear motion of the beam particles, especially moving away from the axis of the elements, is a common issue, and it becomes essential to consider intrinsic field nonlinearities. The main sources of nonlinear magnetic fields in the RCS are as follows: fringes of the main dipole and quadrupole magnets, sextupole fields used for the chromatic correction, leak fields from the injection and extraction beam lines, etc. In this paper, we will discuss influences of the intrinsic field nonlinearities and a cure for the induced betatron resonances, based on single-particle and multi-particle tracking simulations. | ||
| WEPCH128 | Virtual Accelerator as an Operation Tool at J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) | 2224 |
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| We developed a virtual accelerator based on EPICS for 3 GeV Rapid-Cycle Synchrotron (RCS) in J-PARC. It is important to have an on-line model of optics parameters, such as tunes, Twiss parameters, dispersion function, at the commissioning stage in a high intensity proton machine. It gives a strong feedback for the RCS operation as a commissioning tool as well as for the studies of beam dynamics issues. Beam position monitors with finite resolutions, a transverse exciter to measure the betatron frequency, and a RF system with variable frequency to simulate off-momentum optics have been implemented into the system. The virtual accelerator system itself and some results of beam dynamics studies will be presented. | ||
| WEPCH186 | Present Status of FFAG Accelerators in KURRI for ADS Study | 2367 |
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| KART (Kumatori Accelerator driven Reactor Test) project is in progress at the Kyoto University Research Reactor Institute (KURRI) since fiscal year 2002. We are now constructing a 150 MeV proton FFAG accelerator complex as a neutron production driver for this project. The whole of this FFAG complex is expected to be in the test operation around the spring in 2006. The developments and the current status of this accelerator complex, including the current status of this project, will be presented. | ||
| WEPLS056 | R&D Status of the High-intense Monochromatic Low-energy Muon Source: PRISM | 2508 |
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| PRISM is a project of a future intense low-energy muon source, which combines monochromaticity and high purity. Its aimed intensity is about $1011-1012 muons per second. The muon beams will have a low kinetic energy of 20MeV so that it would be optimized for the stopped muon experiments such as searching the muon lepton flavor violating processes. PRISM consists of a pion capture section, a pion/muon transfer section and a phase rotation ssection. An FFAG is used as the phase rotator to achieve the monochromatic muon beams. This paper will describe design status of these sections as well as construction status of PRISM-FFAG. | ||
| THPCH028 | Crystalline Beams at High Energies | 2841 |
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Previously it was shown that by crystallizing each of the two counter-circulating beams, a much larger beam-beam tune shift can be tolerated during the beam-beam collisions; thus a higher luminosity can be reached for colliding beams*. On the other hand, crystalline beams can only be formed at energies below the transition energy of the circular accelerators**. In this paper, we investigate the formation of crystals in two types of high-transition-energy lattices, one realized by three-cell missing dipole modules and the other with negative bends. The latter type satisfies the maintenance condition for a crystalline beam***.
*J. Wei and A.M. Sessler, “Colliding crystalline beams”, EPAC98, p. 862. **J. Wei et al. Physical Review Letters, 73 (1994) p. 3089.***J. Wei et al. Physical Review Letters, 80 (1998) p. 2606. |
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| THPCH054 | SIMPSONS with Wake Field Effects | 2910 |
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| Simpsons, which is originally developed by S. Machida, is the program which calculates the space charge effect to the beam in the ring. The wake field effect to the beam is also installed in this program, because the emittance growth not only due to the space charge effect, but also due to the wake field effect is the important issue. The results of the simulation in J-PARC case are also represented. | ||
| WEPCH141 | Accelerator Physics Code Web Repository | 2254 |
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| In the framework of the CARE HHH European Network, we have developed a web-based dynamic accelerator-physics code repository. We describe the design, structure and contents of this web repository, illustrate its usage, and discuss our future plans. |