Single Shot Spatial and Temporal Coherence Properties of the SLAC Linac Coherent Light Source in the Hard X-Ray Regime
Single Shot Spatial and Temporal Coherence Properties of the SLAC Linac Coherent Light Source in the Hard X-Ray Regime
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DOI：
10.1103/physrevlett.108.024801
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发表时间：
2012-01-11
影响因子：
8.6
通讯作者：
Gruebel, G.
中科院分区：
文献类型：
--
作者：
Gutt, C.;Wochner, P.;Gruebel, G.
我们测量了SLAC的直线加速器相干光源(LCLS)在9keV光子能量下的横向和纵向相干特性。胶体纳米粒子沿正向记录的散斑图样产生了聚焦LCLS光束的横向相干特性。用原子分辨率记录的金纳米粉末的散斑图案使我们能够测量X射线束光谱特性的逐个变化。聚焦光束在横向完全相干，模数接近1。单色器后的平均纵模数目约为14.5个，平均相干时间tau(C)=(2.0+/-1.0)fs。数据表明，对于(100+/-14)飞秒长的电子脉冲，单色仪后面的平均X射线脉冲持续时间为(29+/-14)飞秒。
We measured the transverse and longitudinal coherence properties of the Linac Coherent Light Source (LCLS) at SLAC in the hard x-ray regime at 9 keV photon energy on a single shot basis. Speckle patterns recorded in the forward direction from colloidal nanoparticles yielded the transverse coherence properties of the focused LCLS beam. Speckle patterns from a gold nanopowder recorded with atomic resolution allowed us to measure the shot-to-shot variations of the spectral properties of the x-ray beam. The focused beam is in the transverse direction fully coherent with a mode number close to 1. The average number of longitudinal modes behind the Si(111) monochromator is about 14.5 and the average coherence time tau(c) = (2.0 +/- 1.0) fs. The data suggest a mean x-ray pulse duration of (29 +/- 14) fs behind the monochromator for (100 +/- 14) fs long electron pulses.