2007 Fiscal Year Final Research Report Summary
Realization of the phase transition of a charged particle beams
| Project/Area Number |
17340079
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Hiroshima University |
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Principal Investigator |
OKAMOTO Hiromi Hiroshima University, Graduate School of Advanced Sciences of Matter, Professor (40211809)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Kiyokazu Hiroshima University, Graduate Schcol of Advanced Sciences of Matter, Assistant Professor (70335719)
NODA Akira Kyoto University, Institute for Chemical Research, Professor (20114605)
OIDE Katsunobu Hiroshima University, High Energy Accelerator Research Organization, Professor (50150008)
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| Project Period (FY) |
2005 – 2007
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| Keywords | crystalline beam / linear Paul trap / nonneutral plasma / space-charge effect / laser coolinp / particle accelerator / ion beam |
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| Research Abstract |
The purpose of this study is to demonstrate the realizability of the phase transition of a charged-particle beam circulating in a storage ring. The molecular dynamics (MD) simulation technique was employed to investigate the possibility of beam crystallization. To experimentally explore the collective motion of a high-quality beam, we developed a table-top system 'S-POD (Simulator for Particle Orbit Dynamics)" that consists mainly of a linear Paul trap, a laser cooler high precision ion detectors, a vacuum system, and various power supplies. S-POD enables one to make a systematic study of collective phenomena in space-charge-dominated beams. Experiments of beam cooling were also carried out at the ion storage ring "S-LSR" of Kyoto University The main results obtained during the term of this project are summarized as follows:
1. Extensive MD simulations were performed, which demonstrate that multi-dimensional Coulomb crystals can be stabilized in a dispersion-free storage ring without the use of tapered dissipative force
2. A Wien filter can naturally extend a longitudinal beam cooling force to the transverse degrees of freedom and, thus, makes it possible to establish a coasting crystalline state when EP beam line density is sufficiently low.
3. Results of S-POD experiments indicate that the stability of a high-quality beam in a storage ring may be affected not only by coherent resonance but also by incoherent resonance.
4 A laser cooling system and a laser-induced fluorescence diagnostic were designed and constructed for S-POD. Ca" ions were successfully Doppler cooled and formed one-dimensional Coulomb crystals.
5. The longitudinal motion of a coasting ^<24>Mg^+beam was laser-cooled in S-LSR (although an ultracold state was not reached due to the lack of transverse dissipation). The one-dimensional ordering of a 7MeV proton beam was observed with an electron cooler switched on.
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