Coherent THZ light source using very short electron bunches from a thermionic RF gun

We have planned to establish intense terahertz light source using coherent radiation from undulator. In order to emit coherent radiation, it is important to generate very short electron beam with a bunch length around lOOfs. Now we have developed an injector to generate such short bunch beam. The injector consists of an Independent Tunable Cells thermionic rf gun (ITC rf gun) and a magnetic bunch compressor. Longitudinal and transverse phase space distribution can be controlled by changing input power of each cells and phase difference between cells in this gun. The compressor can change compression rate R₅₆ and 2^nd order dispersion effect by 2 sets of quadrupoles and a set of sextupoles, respectively. Test model of ITC rf gun was manufactured and basic parameters were measured. From tracking simulation, it has been turned out the bunch compressor can reduce to bunch length less than lOOfs. In this paper, we show overview of the coherent terahertz light source and the detail of the ITC rf gun and the bunch compressor.