1992 Fiscal Year Final Research Report Summary
STUDY OF COHERENT SYNCHROTRON RADIATION AND CHERENKOV RADIATION
| Project/Area Number |
03402010
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理学一般
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
IKEZAWA Mikihiko Res.Inst.Sci.Meas.Tohoku Univ. Professor, 科学計測研究所, 教授 (10004334)
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| Co-Investigator(Kenkyū-buntansha) |
ISHI Kimihiro Res.Inst.Sci.Meas.Tohoku Univ. Res.Assistant, 科学計測研究所, 助手 (00125494)
SHIBATA Yukio Res.Inst.Sci.Meas.Tohoku Univ. Res.Assistant, 科学計測研究所, 助手 (70006154)
OHSAKA Toshiaki Res.Inst.Sci.Meas.Tohoku Univ. Assoc.Prof., 科学計測研究所, 助教授 (20152100)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Synchrotron radiation / SR / coherent synchrotron radiation / Cherenkov radiation / transition radiation / far-infrared / millimeter wave / linear accelerator |
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| Research Abstract |
The electrons from a linear accelerator is confined in a short bunch whose longitudinal length is a few millimeters. In our study we have used linear accelerators at laboratory for Nuclear Science, Tohoku University and at Research Reactor Laboratory, Kyoto University to observe coherent synchrotron radiation. The observed spectrum in either case had a peak at a wavelength around 1 to 4 mm and the intensity was enhanced by a factor of several orders of magnitude compared with that of ordinary radiation. The dependence of the intensity on the beam current and the polarization of the radiation were in agreement with theory. During the study, we observed for the first time coherent transition radiation which was emitted when the electrons passed through a thin metallic foil. Its spectrum and the enhancement of the intensity due to the coherent effect ware similar to those of the coherent synchrotron radiation. The dependence of the intensity on the emission length and the angular distribu
… More
tion of the intensity were in accordance with theory. Further, we have observed coherent transition radiation using a linear accelerator at Osaka University. We have determined the diameter and the emittance of the beam, and the longitudinal distribution of the electrons in a bunch. Coherent transition radiation has been proved to be a useful means of the beam diagnosis. Thus, the properties of transition radiation in the long wavelength region have been studied by the coherent radiation. Coherent transition radiation and synchrotron radiation have been confirmed to be useful sources with continuous spectra.
We have pointed out that it is important to distinguish the contribution from the transition radiation from that of the Cherenkov process in the case of the Cherenkov radiation from a bounded trajectory of the electron. Further, we have confirmed experimentally that the emission length must be longer than the formation zone in order that effective radiation of the Cherenkov process occurs. Less
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