Ishiwata, K.
(Ken-ichiro Ishiwata)

THPOS15 Tunability and Power Characteristics of the LEBRA Infrared FEL
Toshinari Tanaka, Ken Hayakawa, Yasushi Hayakawa, Akira Mori, Kyoko Nogami, Isamu Sato, Kazue Yokoyama (LEBRA, Funabashi), Ken-ichiro Ishiwata, Koichi Kanno, Keisuke Nakao, Takeshi Sakai (Graduate School of Science and Technology, Funabashi)

Application of the infrared (IR) Free-Electron Laser (FEL) was started in October 2003 at the Laboratory for Electron Beam Research and Application (LEBRA) of Nihon University. The FEL system consisted of silver-coated copper mirrors has demonstrated wavelength tunability ranged from 940 to 6100 nm as a function of the electron energy and the undulator K-value. Wavelength dependence of the FEL output power has been measured in term of different electron beam currents, electron energies and the undulator K-values. Approximate 25 mJ/macropulse has been obtained in the range 2 to 3 microns, which corresponds to peak power of 2 MW, provided that the FEL pulse length is 0.4 ps as resulted from the measurement by an interferometric method. The power decrease observed in the longer wavelength range is due to a large diffraction loss in the FEL guiding optics and the vacuum ducts.