基于轨道控制的FEL圆偏振辐射的产生与空间分离  

Generation and spatial separation of circular polarized FEL radiations by orbit control

作　　者：易怀千 王晓凡 张未卿 Yi Huaiqian;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,辽宁大连110623

出　　处：《强激光与粒子束》2024年第7期155-161,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：研究了在自由电子激光设施中产生高偏振度圆偏振辐射的技术方案。该方案将工作在反向渐变模式的平面波荡器和常规椭圆极化波荡器以前后连接的方式进行排布,并通过波荡器之间的矫正磁铁对电子束进行轨道控制。在平面波荡器部分利用偏转磁铁使电子束偏向传输,所产生线偏振辐射也将偏轴传播,脉冲能量为0.357μJ。在进入椭圆极化波荡器之前校正电子束的轨道和前进方向,使得带有微群聚结构的电子束沿轴线正向传输,其产生的圆偏振辐射能量为92.39μJ。圆偏振辐射将沿轴向传输,在一定距离后可实现其与线偏振辐射在空间上的分离。通过数值模拟分析了电子束偏转对辐射光性质所产生的影响。Circularly polarized radiation in the X-ray region is required by many experimental applications.Such demands can be met at FEL facilities by mounting few helical undulators after the planar undulators.For obtaining high degree of circular polarized radiation,the reverse taper technique is often used,where in the planar section,significant bunching of the electron beam is accumulated while the output linear polarized radiation power is suppressed.This paper investigates the technique of spatially separating the background weak linear radiation by first transversely deflecting the electron beam with dipole kicker magnets in the planar undulator section and correcting its orbit and traveling direction before entering the helical undulators.The resulting linearly and circularly polarized radiations will propagate in slightly different directions and can be separated spatially.Numerical simulations are performed to analyze the impact of electron beam deflection on the radiation properties.

关 键 词：自由电子激光 圆偏振辐射 反向渐变波荡器 电子束偏转 

分 类 号：TN248.6[电子电信—物理电子学]