R. Kato, T. Okita, R. A. V. Kumar, T. Igo, T. Konishi, M. Kuwahara, M. Fujimoto, S. Mitani, S. Okuda, S. Suemine and G. Isoyama
Institute of Scientific and Industrial Research, Osaka University
We have been conducting experiments to generate Self-Amplified Spontaneous Emission (SASE) in the far-infrared region and to measure its characteristics, using the high intensity single bunch beam accelerated with the L-band linac at the Institute of Scientific and Industrial Research (ISIR), Osaka University. We reported last year that the high-intensity infrared-light was observed when the single-bunch electron beam with a peak current higher than 1 kA passed through a 32-period planar wiggler with the period length of 6 cm and that it was concluded to be due SASE, judging from the intensity variation with the K-value of the wiggler. We have measured wavelength spectra of SASE in the far-infrared region. SASE emitted in the wiggler by the single bunch beam of 12 - 13 MeV energy was guided through an evacuated optical transport line to the measurement room, and then measured in the wavelength region between 100 and 200 
m using a grating monochromator and a liquid-He-cooled Ge:Ga detector. Some of the measured spectra show a few broad peaks. We are checking reproducibility of the experiments and analyzing the measured data. We will report results of these experiments and analysis.