谐波驱动自种子自由电子激光方案模拟  

Simulation of harmonic lasing self-seeded free electron laser

作　　者：涂凌君 王晓凡 张未卿 Tu Lingjun;Wang Xiaofan;Zhang Weiqing(Institute of Advanced Science Facilities,Shenzhen 518107,China;Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 110623,China)

机构地区：[1]深圳综合粒子设施研究院,广东深圳518107 [2]中国科学院大连化学物理研究所,大连辽宁110623

出　　处：《强激光与粒子束》2024年第7期162-168,共7页High Power Laser and Particle Beams

基　　金：中国科学院科研仪器设备研制项目(GJJSTD20220001);国家自然科学基金项目(22288201)。

摘　　要：在自由电子激光(FEL)中,谐波驱动自种子(HLSS)可以减小自放大自发辐射(SASE)机制的辐射带宽、提高X射线波段FEL的谱亮度,其原理已被FLASH、PAL、European XFEL等实验室验证。HLSS可改善SASE FEL的相干性,但同时相对SASE并没有提出新的硬件需求,因此可以很方便地应用于国内在建或运行在SASE机制的自由电子激光装置。本文对HLSS方案实现窄带宽效果的原理进行了归纳,给出了波荡器参数的定量条件;随后使用深圳中能高重复频率X射线自由电子激光的典型参数进行模拟,模拟结果表明在出光波长为4.5 nm与6.75 nm时,HLSS的带宽减小至SASE的1/2左右,同时谱亮度提高至2倍左右。Among free electron laser(FEL)schemes,the Harmonic Lasing Self-Seeded(HLSS)scheme can reduce the radiation bandwidth of self amplified spontaneous emission(SASE)and improve the spectral brightness of FEL in X-ray band.The principle of HLSS has been verified at FLASH,PAL,European XFEL and other laboratories.The HLSS scheme can improve the coherence of a SASE FEL without additional hardware,so it can be easily applied to domestic facilities under construction or running in SASE scheme.In this paper,the principle of the HLSS scheme to achieve narrow bandwidth is summarized,and the quantitative conditions of the undulator parameters are given.Typical parameters of Shenzhen superconducting soft X-ray free electron laser are used to simulate the HLSS scheme.Simulation results show that the bandwidth in the HLSS scheme can be reduced to about 1/2 of the bandwidth in SASE,and the spectral brightness can increase to about 2 times,when the output wavelengths are 4.5 nm and 6.75 nm.

关 键 词：谐波辐射 自种子 自放大自发辐射 窄带宽 纵向相干性 自由电子激光 

分 类 号：TN248.6[电子电信—物理电子学]