The study of some key technologies for a compact Terahertz Source Based on Free Electron Lasers

In this paper some key technologies of a compact Terahertz Source Based on Free Electron Lasers are studied. In order to obtain a compact Terahertz Source, an independent tunable electron gun played a dominant role. The independent tunable electron gun was calculated firstly. The electron gun can create high-brightness and short-pulse beams (less than 2 ps). The energy spread is less than 0.5%, the normalized rms beam emittance and longitudinal rms emittance are both low. So the alpha magnet is not needed. Secondly, electron beams accelerated in a linear accelerator are calculated. By designing the linac carefully the energy of these electron beams, 10 MeV can be obtained in nearly 0.6 m and the energy spread is also less than 0.5%. Thus these electron beams emerging from the linac enter an undulator and the Terahertz radiation is emitted from these beams by a bending magnet. The dimensions of the whole system are less than 3 m . A compact Terahertz source can be obtained.