摘要
外种子型高增益自由电子激光(FEL)可用于产生稳定、全相干的短波长辐射脉冲.然而单级外种子型FEL的谐波转换效率有限,难以用于产生全相干的硬X射线辐射.本文提出了一种新型的双电子束、两级级联回声高次谐波产生(EEHG)的运行机制.在这种新机制中,两台独立的加速器分别用于产生软X射线FEL和硬X射线FEL所需的电子束,且电子束的参数可以根据需要进行独立的调谐.第一级软X射线FEL的输出辐射经过单色器后将作为第二级硬X射线FEL的种子激光,这保证了最终辐射脉冲的相干性.我们采用从头至尾的模拟方法对这一新机制进行了详细的模拟研究,模拟结果表明双电子束、两级级联EEHG可用于产生稳定、全相干的硬X射线FEL.
The ability to generate stable and coherent short wavelength radiation is a great promise of the externally seeded free-electron laser. However, the fre- quency up-conversion efficiency is limited to a small number in a single stage setup. In this paper, we propose a new scheme to produce coherent hard X-ray FEL with two- beam based two-stage echo-enabled harmonic generation configuration. Electron beams with quite different proper- ties are separately used in each stage and a monochromator is adopted to purify the radiation from first stage for seeding the second stage. Three-dimensional start-to-end simulations have been performed with realistic parameters to show the feasibility of the proposed scheme.
基金
supported by the National Development and Reform Commission([2013]2347)
National Natural Science Foundation of China(11475250)
the Shanghai Natural Science Foundation(13ZR1464700)
