Measurement of a chirped pulse generation from the ERL-FEL

Iijima, Hokuto; Hajima, Ryoichi; Nagai, Ryoji; Minehara, Eisuke; Yamauchi, Toshihiko

We report the construction of FEL transport line and the measurement method of chirped FEL pulse. An infrared-chirped pulse is an effective way of dissociating molecules. The chirped FEL pulse oscillator is operated by the JAERI-FEL superconducting accelerator, in which a long pulse of electron beam is produced. Until now, the chirped pulse was measured to be = 14.3% with the wavelength of 23.3 m and the pulse width of 319 fs at FWHM by an autocorrelation. In order to measure the correlation between time and frequency in the chirped pulse directly, the frequency-resolved optical grating (FROG) is developing. Since the measurement is performed in new experimental room, the vacuum transport line guiding the FEL to the room has been constructed.