THz辐射已广泛应用于科学研究、国家安全和工程技术等领域，近年来在辐射源、传输技术和探测技术等方面都得到了快速发展。基于相对论电子束的自由电子激光（FEL）是产生强场THz辐射的重要技术手段，国内外多个加速器实验室已经或正在发展这项技术。目前国际上THz FEL都采用低增益振荡器技术，不易获得同时具有高重复频率和较高峰值功率的THz辐射，且难以实现短脉冲。本项目将结合射频超导加速技术开展种子放大型THz FEL辐射的理论和实验研究，通过解决THz种子源、电子束团调控和THz的有效放大等关键技术问题，在国际上首次实现种子放大型THz FEL辐射机制并产生既具有高重复频率又具有较高脉冲峰值功率的短脉冲THz辐射。本项目在发展THz辐射源技术的同时，也可以促进与高重频短脉冲THz辐射相关的应用研究。

Since THz has been widely applied in the fields of scientific research, security and engineering, the techniques include THz source, transportation and detection develop very fast. Free electron laser based on relativistic electron beam is an important technique to produce high field THz radiation and there are many accelerator laboratories have been involved in this technology in the world. Up to now, only oscillator FEL has been adopted for THz FEL and it is difficult to produce THz radiation with high repetition rate and high peak power simultaneously. In this project, we will develop seeded FEL technology by using high repetition rate electron pulses from SRF linac. The key problems of THz source as a seed, manipulation of electron pulses and efficient amplification of THz seed will be solved. It is expected to realize the seeded FEL THz production mechanism and produce THz radiation with high peak power, high repetition rate and short pulse length as first time. Meanwhile developing the THz radiation source, this project will also promote the related applications.