上海软X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser,SXFEL)需1个分辨率达到亚μm量级的束流位置测量系统,并采用基于束流准直的方法实现波荡器段电子束与光子束的紧密重合。为此设计研制了1个由C波段腔式探头、单...上海软X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser,SXFEL)需1个分辨率达到亚μm量级的束流位置测量系统,并采用基于束流准直的方法实现波荡器段电子束与光子束的紧密重合。为此设计研制了1个由C波段腔式探头、单路混频至低中频的射频前端以及自主研发的专用数字信号束流位置处理器(digital beam position monitor processor,DBPM)构成的腔式束流位置测量(cavity beam position monitor,CBPM)系统。本文对系统的设计、软硬件结构、系统搭建进行了介绍,并基于漂移段搭建的3个紧邻的CBPM阵列完成了在线系统性能评估。束流实验结果表明,在束团电荷量为500 pC、系统动态范围在±800μm的条件下,位置分辨率可达880 nm,这也是国内首次研制成功可在线运行的具有亚μm位置分辨率的CBPM系统。此外,采用CBPM的相位腔进行相对束团电荷量、束团到达时间的测量,其性能评估结果也均优于SXFEL设计要求。展开更多
A two-stage echo-enabled harmonic generation(EEHG)scheme is proposed for a superconducting linacdriven FEL to produce coherent hard X-rays.Electron beams of quite different bunch lengths are separately used in each st...A two-stage echo-enabled harmonic generation(EEHG)scheme is proposed for a superconducting linacdriven FEL to produce coherent hard X-rays.Electron beams of quite different bunch lengths are separately used in each stage of EEHG,and a monochromator is designed to purify the radiation from the first stage for seeding the second stage.Theoretical analysis and 3D simulations indicate that the proposed scheme can generate high-repetition-rate coherent hard X-ray pulses directly from a conventional UV seed laser.展开更多
Besides the original seeded undulator line,in the soft X-ray free-electron laser(SXFEL) user facility in Shanghai,a second undulator line based on self-amplified spontaneous emission is proposed to achieve 2-nm laser ...Besides the original seeded undulator line,in the soft X-ray free-electron laser(SXFEL) user facility in Shanghai,a second undulator line based on self-amplified spontaneous emission is proposed to achieve 2-nm laser pulse with extremely high brightness.In this paper,the beam energy deviation induced by the undulator wakefields is numerically calculated,and 3D and 2D results agree well with each other.The beam energy loss along the undulator degrades the expected FEL output performances,i.e.,the pulse energy,radiation power and spectrum,which can be compensated with a proper taper in the undulator.Using the planned time-resolved diagnostic,a novel experiment is proposed to measure the SXFEL longitudinal wakefields.展开更多
文摘上海软X射线自由电子激光装置(Shanghai Soft X-ray Free Electron Laser,SXFEL)需1个分辨率达到亚μm量级的束流位置测量系统,并采用基于束流准直的方法实现波荡器段电子束与光子束的紧密重合。为此设计研制了1个由C波段腔式探头、单路混频至低中频的射频前端以及自主研发的专用数字信号束流位置处理器(digital beam position monitor processor,DBPM)构成的腔式束流位置测量(cavity beam position monitor,CBPM)系统。本文对系统的设计、软硬件结构、系统搭建进行了介绍,并基于漂移段搭建的3个紧邻的CBPM阵列完成了在线系统性能评估。束流实验结果表明,在束团电荷量为500 pC、系统动态范围在±800μm的条件下,位置分辨率可达880 nm,这也是国内首次研制成功可在线运行的具有亚μm位置分辨率的CBPM系统。此外,采用CBPM的相位腔进行相对束团电荷量、束团到达时间的测量,其性能评估结果也均优于SXFEL设计要求。
基金partially supported by the National Development and Reform Commission([2013]2347)National Natural Science Foundation of China(No.11475250)the Youth Innovation Promotion Association CAS(2015209)
文摘A two-stage echo-enabled harmonic generation(EEHG)scheme is proposed for a superconducting linacdriven FEL to produce coherent hard X-rays.Electron beams of quite different bunch lengths are separately used in each stage of EEHG,and a monochromator is designed to purify the radiation from the first stage for seeding the second stage.Theoretical analysis and 3D simulations indicate that the proposed scheme can generate high-repetition-rate coherent hard X-ray pulses directly from a conventional UV seed laser.
基金supported by the National Natural Science Foundation of China(Nos.11475250 and 11322550)Ten Thousand Talent Program
文摘Besides the original seeded undulator line,in the soft X-ray free-electron laser(SXFEL) user facility in Shanghai,a second undulator line based on self-amplified spontaneous emission is proposed to achieve 2-nm laser pulse with extremely high brightness.In this paper,the beam energy deviation induced by the undulator wakefields is numerically calculated,and 3D and 2D results agree well with each other.The beam energy loss along the undulator degrades the expected FEL output performances,i.e.,the pulse energy,radiation power and spectrum,which can be compensated with a proper taper in the undulator.Using the planned time-resolved diagnostic,a novel experiment is proposed to measure the SXFEL longitudinal wakefields.
