| Paper |
Title |
Page |
| TUPLT024 |
A Comparison of High Current Ion Beam Matching from an Ion Source to a RFQ by Electrostatic and by Magnetic Lenses
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1192 |
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- R. Becker, R.A. Jameson, A. Schempp
IAP, Frankfurt-am-Main
- T. Hata, N. Hayashizaki, H. Kashiwagi, K. Yamamoto
RLNR, Tokyo
- T. Hattori, M. Okamura, A. Sakumi
RIKEN, Saitama
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In order to improve the ?direct? injection scheme of the Riken Nd-YAK-laser driven ion source into a RFQ rf-accelerator, several basic methods have been investigated and compared, in order to transform the initially divergent ion beam into a convergent one, needed for matching the high current (100 mA C6+) ion beam at an energy of 100 keV to a RFQ. From the point of power supplies and break down characteristics, the simplest solution is a decelerating electrostatic lens, with the decelerating electrode operated on ion source potential. Due to the strong divergence of the ions beam after acceleration, this lens will be filled to an aperture, which causes strong aberrations. Therefore, we also investigated to use an accelerating potential on the lens electrode. This reduces significantly the filling of the lens and the emittance growth is only a factor of 3, as compared to the decelerating lens with a factor of 30! Finally we have been looking also into a magnetic matching system, which can match the ion beam to the RFQ with virtually no emittance growth.
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| TUPLT190 |
Acceleration of Polarized Beams using Multiple Strong Partial Siberian Snakes
|
1577 |
| |
- T. Roser, L. Ahrens, M. Bai, E.D. Courant, J. Glenn, R.C. Gupta, H. Huang, A.U. Luccio, W.W. MacKay, N. Tsoupas, E. Willen
BNL, Upton, Long Island, New York
- M. Okamura, J. Takano
RIKEN, Saitama
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Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.
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| WEPLT114 |
Field Measurements in the AGS Warm Snake
|
2113 |
| |
- J. Takano, M. Okamura
RIKEN, Saitama
- R. Alforque, R. Belkin, G. Ganetis, A.K. Jain, W.W. MacKay, T. Roser, R. Thomas, J. Tuozzolo
BNL, Upton, Long Island, New York
- T. Hattori
RLNR, Tokyo
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A new warm snake has been produced for avoiding the transverse coupling resonance in the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). The warm snake is the world?s first normal conducting helical dipole partial snake which has a double pitch structure to allow spin rotation with no net beam offset or deflection with a single magnet. The warm snake is 2.6m long, and has a field of 1.5 Tesla for a 9 degrees spin rotation. The pitches, current density, and shims were optimized by using OPERA_3D / TOSCA. The magnetic field harmonics have been measured using a system of 51 mm long, 34 mm radius tangential coils. The axial variation of the dipole field angle agrees very well with the calculations, indicating no significant construction errors. However, the measured transfer function shows a discrepancy of 4% which may be caused by BH-curve differences, deformation of the iron and packing factor of the laminations. To correct the beam trajectory the operating current was adjusted and shims were installed on the end plates. These optimization studies, and comparison with measurements, will be shown.
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| THPLT079 |
The Study of APF-IH Linac
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2676 |
| |
- K. Yamamoto, T. Hattori, K. Yamamoto
RLNR, Tokyo
- M. Okamura
RIKEN, Saitama
- S. Yamada
NIRS, Chiba-shi
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We have manufactured the IH linac with Alternating Phase Focus as the test machine of medical accelerator injection. It will accelerate C4+ ion up to 2MeV/u from 40 keV/u, the tank length is around 1.5m, operation frequency is 100MHz. Furthermore, We have succeeded the acceleration test using proton with simple acceleration system consist of P.I.G. ion source, bending magnets and focus lenses, less than 5m long. Otherwise, We have been making the program of beam dynamics with the results of the electro-magnetic simulation soft (Micro-Wave-Studio,OPERA-3D), it has the merit of easily to calculate the 3D- beam dynamics in the tank. We will report the some results of the test and the beam simulation and the comparisons.
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| TUPLT025 |
Matching of a C6+ Ion Beam from a Laser Ion Source to a RFQ
|
1195 |
| |
- R. Becker, R.A. Jameson, A. Schempp
IAP, Frankfurt-am-Main
- T. Hattori
RIKEN, Saitama
- N. Hayashizaki, H. Kashiwagi
RLNR, Tokyo
- M. Okamura
RIKEN/RARF/CC, Saitama
- K. Yamamoto
RIKEN/RARF/BPEL, Saitama
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A laser ion source, driven by a Nd-YAG laser can provide more than 100 mA of C6+ ions for a duration of about 1 μs, which is well matching the task of single-turn injection into synchrotrons for hadron tumor therapy with light ions. The ?direct? injection scheme has been improved by providing a design, which reduces the surface field strength to less than 30 kV/cm on all critical parts on relative negative potential. The new design keeps the advantage of divergent ion emission and acceleration, which seems to be the only way to keep the surface fields in limits, but includes a decelerating electrostatic lens on birth potential of the ions to refocus the emerging ion beam to the RFQ entrance. The whole design is very compact and allows for electrostatic steering between the ion source and the RFQ.
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