The High Brightness Photo-injector for THz Cur/Vuv Fel at Nsrrc
An-ping Lee1*, Ming-Chang Chou1, Jiing-Yi Hwang1, Wai-Keung Lau1, Nuan-Ya Huang1, Cheng-Chih Liang1, Kuo-Tung Hsu1, Gwo-Huei Luo1, Ching-Shiang Hwang1
1National Shychrotron radiation research center, Hsinchu, Taiwan
* Presenter:An-ping Lee
A high brightness photo-injector has been build for THz coherent undulator radiation and VUV free electron laser test facility at NSRRC. In the first phase, the photo-injector was used to produce ultra-short electron bunches by velocity bunching method for THz CUR generation. The photo-injector system is equipped with a photocathode rf gun, followed by a solenoid for emittance compensation. A 5.2 m S-band linac is used to accelerate electron beams or compress beams by velocity bunching. Beam diagnostic tools such as ICT and spectrometer are installed between rf gun and linac. Downstream the linac a quadruple magnet was use for emittance measurement by quadruple scan method. Since the beam emittance will grow during the velocity bunching process, a solenoid system was installed to reduce the emmitance growth. The coherent transition radiation used to measure the bunch length was set up downstream the linac. The operating parameters of the photo-injector need to be optimized so that bunches passing through the undulator will produce coherent undulator radiation.

Keywords: Photo-injector , THz coherent undulator radiation