| Paper | Title | Page |
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| MOPMP009 | Effect of Initial Parameters on the Super Flat Beam Generation with the Phase-Space Rotation for Linear Colliders | 442 |
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Funding: This work is partly supported by Japan-US Cooperative grant for scientific studies, Grant aid for scientific study by MEXT Japan (KAKENHI) Kiban B. Linear collider is a concept to realize e+e− collision beyond the limitation of the ring colliders by the synchrotron radiation. To obtain an enough luminosity, eg. 1.0·10+34 cm-2sec-1, the beam is focused down to nano-meter size with a high aspect ratio. This super flat beam is useful to improve the luminosity and to compensate the beam-beam effect, eg. Beamstrahlung. In a conventional design, the super-flat beam is produced by radiation damping in a storage ring. We propose to produce this super-flat beam with phase-space rotation techniques. We employ both Round to Flat Beam Transformation and Transverse to Longitudinal Emittance eXchange, the super flat beam can be generated by controlling the space-charge effect which spoiled the performance. We present the RFBT performance with respect to the initial conditions, i.e. beam size, initial emittance, solenoid field (strength and profile), etc. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPMP009 | |
| About • | paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019 | |
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| TUPGW033 | Status of Test-Accelerator as Coherent THz Source (t-ACTS) at ELPH, Tohoku University | 1475 |
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| A test-Accelerator as Coherent Terahertz Source (t-ACTS) has been under development at the Research Center for Electron Photon Science (ELPH), Tohoku University, in which an intense coherent terahertz radiation is generated from the femtosecond electron pulses. Velocity bunching scheme in a traveling accelerating structure is employed to generate femtosecond electron pulses, and the generation of femtosecond electron pulses was confirmed by spectrum analysis of coherent transition radiation using Michelson interferometer. Coherent transition radiation and coherent undulator radiation in the terahertz (THz) region from the short electron pulses has been demonstrated, and their characteristics such as frequency spectrum, spatial distribution and polarization were measured and compared with theoretical calculations. We have succeeded to generate the coherent transition radiation up to approximately 5 THz and the coherent undulator radiation with narrow bandwidth from 2.6 to 3.4 THz. At present, development of a variable polarized THz light source using a crossed-undulator system is being carried out. In addition, we are developing a nondestructive beam monitor using Cherenkov radiation emitted from the electron pulses. The status of t-ACTS will be presented in this conference. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW033 | |
| About • | paper received ※ 17 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| TUPRB038 | Characteristics of Polarized Coherent Radiation in Thz Region From a Crossed-Undulator | 1769 |
| SUSPFO043 | use link to see paper's listing under its alternate paper code | |
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| A variable polarized THz light source using a crossed-undulator configuration has been developed at Research Center for Electron Photon Science (ELPH), Tohoku University. It consists of two planar undulators of which deflecting planes cross at right angles and a phase shifter for phase adjustment. Polarization of the crossed-undulator has observation angle dependence due to that of radiation wavelength and optical path length difference between two radiations. That limits an angular range maintaining the identical polarization state. Assuming undulator parameters for our experiment (a fundamental frequency 1.9 THz and a number of periods seven) degree of circular polarization larger than 0.9 can be obtained only in the range of 2.2 mrad, i. e. 13% of the radiation angular spread. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB038 | |
| About • | paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019 | |
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| WEPGW031 | Measurement of Cherenkov Diffraction Radiation from a Short Electron Bunches at t-ACTS | 2536 |
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| Cherenkov Diffraction Radiation (ChDR) can be considered as a tool of non-destructive beam diagnostics. It also has the feature that the photon flux of ChDR is proportional to the thickness of the dielectric used as the radiator and can be much larger than ordinary diffraction radiation. An experimental set-up for the measurement of coherent ChDR from short electron bunches of about 100 fs is being prepared at t-ACTS, Tohoku University. Results of a basic experimental study about coherent ChDR will be presented. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPGW031 | |
| About • | paper received ※ 16 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019 | |
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