直流-射频超导(direct current-superconducting radio frequency,DC-SRF)光阴极电子枪是由北京大学射频超导加速器实验室提出并发展的一种连续波电子源,可产生MHz及以上重复频率、皮秒至亚皮秒脉冲、Me V能量的电子束.作为一类重要的...直流-射频超导(direct current-superconducting radio frequency,DC-SRF)光阴极电子枪是由北京大学射频超导加速器实验室提出并发展的一种连续波电子源,可产生MHz及以上重复频率、皮秒至亚皮秒脉冲、Me V能量的电子束.作为一类重要的超导型光阴极电子枪,DC-SRF将具有高量子效率的半导体光阴极与射频超导加速腔分离,成功地解决了二者之间的兼容问题,并具有结构紧凑、暗电流低等优点.DC-SRF光阴极电子枪的研发经历了样机、DC-SRF-I及DC-SRF-II三个阶段,其中,DC-SRF-I于2014年实现稳定载束运行,并开展了系列应用实验;DCSRF-II于2021年建成,2022年实现100 p C束团电荷量、1 MHz重复频率的连续波模式运行,暗电流小于1 pA,归一化发射度达到亚mm-mrad级,综合性能指标处于领先地位.本文总结DC-SRF电子枪的研究工作,主要内容包括DCSRF-I电子枪、DC-SRF-II电子枪、光阴极与驱动激光等.展开更多
A high repetition rate,picosecond terahertz(THz)parametric amplifier with a LiNbO3(LN)crystai has been demonstrated in this work.At a 10 kHz repetition rate,a peak power of 200 W and an average power of 12 pW have bee...A high repetition rate,picosecond terahertz(THz)parametric amplifier with a LiNbO3(LN)crystai has been demonstrated in this work.At a 10 kHz repetition rate,a peak power of 200 W and an average power of 12 pW have been obtained over a wide range of around 2 THz;at a 100 kHz repetition rate,a maximum peak power of 18 W and an average power of 10.8 pW have been obtained.The parametric gain of the LN crystal was also investigated,and a modified Schwarz-Maier model was introduced to interpret the experimental results.展开更多
High-gain harmonic generation(HGHG) is effective to produce fully coherent free-electron laser(FEL) pulses for various scientific applications. Due to the limitation of seed lasers, HGHG typically operates at a low re...High-gain harmonic generation(HGHG) is effective to produce fully coherent free-electron laser(FEL) pulses for various scientific applications. Due to the limitation of seed lasers, HGHG typically operates at a low repetition rate.In this paper, a harmonic-enhanced HGHG scheme is proposed to relax the peak power requirement for the seed laser,which can therefore operate at megahertz and a higher repetition rate. Moreover, the setup of the scheme is compact and can be adopted in an existing single-stage HGHG facility to extend the shortest achievable wavelength. Simulations show that FEL emission at 13.5 nm(20th harmonic) can be obtained with a 270 nm, 1 MW(peak power) seed laser.展开更多
文摘直流-射频超导(direct current-superconducting radio frequency,DC-SRF)光阴极电子枪是由北京大学射频超导加速器实验室提出并发展的一种连续波电子源,可产生MHz及以上重复频率、皮秒至亚皮秒脉冲、Me V能量的电子束.作为一类重要的超导型光阴极电子枪,DC-SRF将具有高量子效率的半导体光阴极与射频超导加速腔分离,成功地解决了二者之间的兼容问题,并具有结构紧凑、暗电流低等优点.DC-SRF光阴极电子枪的研发经历了样机、DC-SRF-I及DC-SRF-II三个阶段,其中,DC-SRF-I于2014年实现稳定载束运行,并开展了系列应用实验;DCSRF-II于2021年建成,2022年实现100 p C束团电荷量、1 MHz重复频率的连续波模式运行,暗电流小于1 pA,归一化发射度达到亚mm-mrad级,综合性能指标处于领先地位.本文总结DC-SRF电子枪的研究工作,主要内容包括DCSRF-I电子枪、DC-SRF-II电子枪、光阴极与驱动激光等.
基金the National Key Research and Development Program of China(No.2017YFA0701000)the National Natural Science Foundation of China(No.11735002).
文摘A high repetition rate,picosecond terahertz(THz)parametric amplifier with a LiNbO3(LN)crystai has been demonstrated in this work.At a 10 kHz repetition rate,a peak power of 200 W and an average power of 12 pW have been obtained over a wide range of around 2 THz;at a 100 kHz repetition rate,a maximum peak power of 18 W and an average power of 10.8 pW have been obtained.The parametric gain of the LN crystal was also investigated,and a modified Schwarz-Maier model was introduced to interpret the experimental results.
基金supported by the National Natural Science Foundation of China(No.11975039).
文摘High-gain harmonic generation(HGHG) is effective to produce fully coherent free-electron laser(FEL) pulses for various scientific applications. Due to the limitation of seed lasers, HGHG typically operates at a low repetition rate.In this paper, a harmonic-enhanced HGHG scheme is proposed to relax the peak power requirement for the seed laser,which can therefore operate at megahertz and a higher repetition rate. Moreover, the setup of the scheme is compact and can be adopted in an existing single-stage HGHG facility to extend the shortest achievable wavelength. Simulations show that FEL emission at 13.5 nm(20th harmonic) can be obtained with a 270 nm, 1 MW(peak power) seed laser.
