Laser-driven soft-X-ray undulator source
Laser-driven soft-X-ray undulator source
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DOI：
10.1038/nphys1404
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发表时间：
2009-11-01
期刊：
影响因子：
19.6
通讯作者：
Gruener, Florian
中科院分区：
文献类型：
--
作者：
Fuchs, Matthias;Weingartner, Raphael;Gruener, Florian
同步加速器和自由电子激光器是最强的X射线辐射源。它们构成了广泛研究的宝贵工具(1)；然而，它们对大规模射频电子加速器的依赖意味着，全世界只有几个这样的来源。激光驱动的等离子体波加速器(2-10)提供了显著增加的加速场，因此有可能将这些X射线源的尺寸和成本缩小到大学实验室的规模。在这里，我们演示了用激光等离子体加速电子束产生软X射线波动体辐射。准直良好的光束产生软X射线脉冲，预期脉冲持续时间类似于10飞秒(从等离子体加速器物理学推断)。我们的源利用一个30厘米长的波荡器(11)和一个1.5厘米长的加速器来提供能量类似于210 MeV的稳定电子束(10)。产生的波荡器辐射的光谱通常由中心在类似于18 nm(基波)的波长处的主峰、靠近9 nm的第二峰(二次谐波)和类似于7 nm的高能截止组成。磁四极透镜(11)确保了有效的电子束传输，并展示了一种能够重复产生可调谐波动器辐射的技术。通过增加电子能量，光源可以扩展到更短的波长。我们的结果为小型实验室开发可调谐、明亮的超短脉冲X射线源开辟了前景。
Synchrotrons and free-electron lasers are the most powerful sources of X-ray radiation. They constitute invaluable tools for a broad range of research(1); however, their dependence on large-scale radiofrequency electron accelerators means that only a few of these sources exist worldwide. Laser-driven plasma-wave accelerators(2-10) provide markedly increased accelerating fields and hence offer the potential to shrink the size and cost of these X-ray sources to the university-laboratory scale. Here, we demonstrate the generation of soft-X-ray undulator radiation with laser-plasma-accelerated electron beams. The well-collimated beams deliver soft-X-ray pulses with an expected pulse duration of similar to 10 fs (inferred from plasma-accelerator physics). Our source draws on a 30-cm-long undulator(11) and a 1.5-cm-long accelerator delivering stable electron beams(10) with energies of similar to 210 MeV. The spectrum of the generated undulator radiation typically consists of a main peak centred at a wavelength of similar to 18 nm (fundamental), a second peak near similar to 9 nm (second harmonic) and a high-energy cutoff at similar to 7 nm. Magnetic quadrupole lenses(11) ensure efficient electron-beam transport and demonstrate an enabling technology for reproducible generation of tunable undulator radiation. The source is scalable to shorter wavelengths by increasing the electron energy. Our results open the prospect of tunable, brilliant, ultrashort-pulsed X-ray sources for small-scale laboratories.