| Paper | Title | Page |
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| TUPSO66 | Transport of Terahertz-Wave Coherent Synchrotron Radiation With a Free-electron Laser Beamline at LEBRA | 383 |
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Funding: This work was supported by JSPS Grant-in-Aid for Challenging Exploratory Research 2365696. Nihon University and AIST have jointly developed terahertz-wave coherent synchrotron radiation (CSR) at Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University. We have already observed intense terahertz-wave radiation from a bending magnet located above an undulator, and confirmed it to be CSR*. To avoid a damage caused by ionizing radiation, we worked on transporting the CSR to an experimental room which was next to the accelerator room. By using a beamline of an infrared free-electron laser, the CSR more than 1 mW was successfully transported to the experimental room. The transport of the CSR and imaging experiments with the CSR at LEBARA will be reported. *: N. Sei et al., “Observation of intense terahertz-wave coherent synchrotron radiation at LEBRA”, J. Phys. D, 46 (2013) 045104. |
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| TUPSO67 | Design Optimization of 100 Kv DC Gun Wehnelt Electrode for FEL Linac at LEBRA | 387 |
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| The 125-MeV electron linac at the Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University has been used for generation of the near infrared FEL and the Parametric X-ray Radiation. In addition, the THz beam generated in a bending magnet became available in the FEL experimental rooms in 2012 by transporting in the FEL optical beam line. The electron gun system for the LEBRA linac can extract the electron beam in three modes, the full bunch, the superimposed and the burst modes. However, the shape of the electron gun wehnelt electrode has not been optimized for the operation with the superimposed or the burst modes; the wehnelt was designed for use in the full bunch operation. The beam trace simulation suggested that the beam extracted from the cathode in the superimposed and the burst modes was slightly lost at the anode due to the strong space charge effect resulted from a high peak extraction current. Therefore, simulation of the beam trace was carried out to optimize the wehnelt shape for the maximum beam extraction efficiency for all the beam operation modes. The present paper reports the result of the simulation on the optimized electron gun design. | ||
| WEPSO65 | LEBRA Free Electron Laser as a Radiation Source for Photochemical Reactions in Living Organisms | 675 |
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| The radiation sources commonly used in plant applications are commercially available lamps developed for human lighting applications (fluorescent, metal halide, high-pressure sodium, incandescent, light-emitting diode, and laser diode). In contrast, free-electron lasers (FELs) such as LEBRA-FEL produce high-energy, tunable pulse radiation and thus are promising radiation sources for photochemical research. An advantage of LEBRA-FEL is that the peak intensity ranges from 0.35 to 6.5 microns which are wavelengths coinciding with the absorption peaks of living organisms. Previously, we established a microscopic irradiation technique for delivering visible FEL light to single cells through a tapered glass rod (< 10 microns). However, it is still unclear whether LEBRA-FEL can produce sufficient radiant energy at wavelengths effective for triggering photochemical reactions in living organisms. The aim of this study was to evaluate the effectiveness of LEBRA-FEL in lettuce-seed germination tests. Results show promotion by red light and inhibition by far-red light, indicating that LEBRA-FEL can be used to control lettuce-seed germination. | ||