FREE-ELECTRON LASER OSCILLATION WITH A MULTIBUNCH ELECTRON-BEAM OF THE 38-MEV L-BAND LINEAR-ACCELERATOR AT ISIR

Free-electron laser oscillation has been achieved with a multibunch el ectron beam generated with the 38 MeV L-band linear accelerator at The Institute of Scientific and Industrial Research in Osaka University. The wavelengths of the observed FEL are 32 to 40 mu m for energies of the electron beams of 17 to 19 MeV. The macropulse length of the beam is 1.8 mu s. The net FEL gain measured at a wavelength of 40 mu m is 2 5%. The tuning range of the length of the optical cavity and the FEL s pectra have also been measured. The total output FEL energy of 12 mJ h as been obtained in the recent experiments at a wavelength of 40 mu m. The intracavity peak power of the FEL is estimated to be about 150 MW .