Du, Y. C. Yan, L.X. JACoW Publishing Geneva, Switzerland The high brightness electron linac based on a photocathode RF gun was established in Tsinghua University for the study of Thomson scattering x-ray and THz radiation light sources. Recent THz radiation research activities with tunable bunch trains, specially on their generation and diagnostics, will be presented. Experiments on coherent undulator radiation, coherent transition radiation, coherent Smith-Purcell radiation, dielectric wakefield radiation were performed. Another part of this talk will be focused on the recent progress in linac based ICS source at Tsinghua University, including the experiments on X/gamma-ray generation, diagnostic, and its applications in advanced X-ray imaging. And the design of a new compact ICS gamma-ray sources will also be discussed in this talk.