We have been developing MIR-FEL driven by an electron linac in Institute of Advanced Energy, Kyoto University. The linac, which consists of a thermionic RF-gun, an s-band accelerator, a bunch compressor, and an undulator, accelerates electron beam up to 40 MeV with micropulse duration of less than 1 ps. The FEL wavelength covers from 5 to 20 μm with several mJ/macropulse has been delivered for users. As an example of the user application, selective phonon excitation in SiC is introduced in this paper. We have been developed a new concept short period undulator. The report on this study will be presented in this paper as well.
