| Paper | Title | Page |
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| MOPEC052 | KEK Digital Accelerator for Material and Biological Sciences | 576 |
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A novel circular accelerator capable of accelerating any ions from an extremely low energy to relativistic energy is discussed. A digital accelerator (DA)* is based on the induction synchrotron concept, which had been demonstrated in 2006. All ions are captured and accelerated with pulse voltages generated by induction acceleration cell (IAC). The IAC is energized by the switching power supply, in which power solid-state conductors are employed as switching elements and their tuning on/off is maneuvered by gate signals digitally manipulated from the circulating signal of an ion beam. Acceleration synchronized with the revolution of the ion beam is always guaranteed. The concept is realized by renovating the KEK 500 MeV booster into the DA, introducing a laser ablation ion source. Ion energy of 85-140 MeV/au and intensity of 10+9 - 10+10 /sec are estimated and these ions will be delivered without any large-scale injector. Companion papers** will discuss more details of instruments of DA. Applications for innovative material sciences and life sciences will be briefly introduced as well as the outline of DA. *K. Takayam, J. of Appl. Phys. 101 (2007) 063304. |
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| MOPEC053 | Ion Source and Low Energy Beam Transport for the KEK Digital Accelerator | 579 |
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KEK digital accelerator (DA) capable of accelerating all species of ion* is an induction synchrotron employing no large scale injectors. At the beginning of its operation, Ar ions from the ECR ion source (ECRIS) embedded in the 200 kV high voltage terminal (HVT) are directly injected into KEK-DA though the low energy BT line (LEBT). The permanent magnet ECRIS was assembled at KEK. Its characteristics such as a charge-state spectrum, emittance, and intensity are presented. The 200 kV HVT has been also assembled at KEK. Its voltage stability in the pulse mode operation, where a plasma of 1 msec is created by x-band microwaves at 10 Hz, is discussed. The LEBT consists of the Eintzel lens, momentum analyzer, B magnets with edge focusing, electrostatic chopper**, and a combination of Q magnets. In the upper LEBT from the ion extraction hall to the entrance of the analyzer, possible charge-state ions are contaminated in the space-charge limit and beam focusing is realized through the Eintzel lens and tandem acceleration gaps. In the lower LEBT from the analyzer to the KEK-DA injection point, the lattice has been optimized so as to meet optics matching at the injection point. *K. Takayama, J. of Appl. Phys. 101 063304(2007), "KEK digital accelerator for material and biological sciences" in this conference |
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| MOPD064 | Bunched Beam Stochastic Cooling at COSY | 834 |
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The stochastic cooling is employed to reduce the momentum spread of accelerated 2 GeV proton beam at COSY. In addition the barrier voltages are successfully used to compensate the mean energy loss of the beam due to the thick internal target such as pellet target. To analyze the experimental results at COSY, we have developed the particle tracking code which simulate the particle behavior under the influences of stochastic cooling force, Schottky diffusion, thermal diffusion and IBS effects. The synchrotron motion due to the RF fields are included with 4th order symplectic way. The simulation results are well in agreement with the observed cooling process for the case of barrier voltage as well as RF field of harmonic number=1. In the present paper, the systematic analysis of the experimental results with use of the developed tracking codes are described. In addition the process of short bunch formation at the heavy ion collider at NICA project is investigated with use of the stochastic cooling. In that case the strong IBS effects are main limiting factor of making and keeping the short bunch as well as the space charge effects. Details of the simulation study will be presented. |
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| MOPD065 | Beam Accumulation with Barrier Voltage and Stochastic Cooling | 837 |
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Anti-proton beam accumulation at CERN and FNAL has been performed with use of stochastic stacking in the momentum space. Thus accumulated beam has a large momentum spread and resultantly large radial beam size with large dispersion ring. In the present proposed scenario, beams from the pre-cooling ring are injected into the longitudinal empty space prepared by the barrier voltages and subsequently the stochastic cooling is applied. After the well cooling, barrier voltages will prepare again the empty space for the next beam injection. We have simulated the stacking process up to 100 stacking with use of the bunched beam tracking code including the stochastic cooling force and the diffusion force such as Schottky diffusion term, thermal diffusion, IBS effects. The synchrotron motion by barrier voltages are included with 4th order symplectic method. Examples of the application to 3 GeV anti-proton beam for the HESR ring in FAIR project are presented as well as the accumulation of heavy ion beam 3.5 GeV/u Au, at the NICA collider at JINR project. |
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| MOPD070 | Numerical Study on Simultaneous Use of Stochastic Cooling and Electron Cooling with Internal Target at COSY | 852 |
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A small momentum spread of proton beam has to be realized and kept in a storage ring during an experiment with a dense internal target such as a pellet target. A stochastic cooling alone does not compensate the mean energy loss by the internal target. Barrier bucket operation will cooperate effectively the energy loss. In addition, the further small momentum spread can be realized with use of an electron cooling. In the present study, the simulation results on the simultaneous use of stochastic cooling and electron cooling at COSY are presented. |