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11.
X‐ray free‐electron lasers (XFELs) generate sequences of ultra‐short spatially coherent pulses of X‐ray radiation. A diffraction focusing spectrometer (DFS), which is able to measure the whole energy spectrum of the radiation of a single XFEL pulse with an energy resolution of ΔE/E? 2 × 10?6, is proposed. This is much better than for most modern X‐ray spectrometers. Such resolution allows one to resolve the fine spectral structure of the XFEL pulse. The effect of diffraction focusing occurs in a single‐crystal plate due to dynamical scattering, and is similar to focusing in a Pendry lens made from a metamaterial with a negative refraction index. Such a spectrometer is easier to operate than those based on bent crystals. It is shown that the DFS can be used in a wide energy range from 5 keV to 20 keV. 相似文献
12.
X-ray diffraction using a coherent beam involves the mutual interference among all the extremities of small crystals. The continuous diffraction pattern so produced can be phased because it can be oversampled. We have thus obtained three-dimensional images of the interiors of Au nanocrystals that show 50 nm wide bands of contrast with [111] orientation that probably arise from internal twinning by dynamic recrystallization during their formation at high temperature. 相似文献
13.
火焰原子吸收光谱法测定鱼腥草、西洋参和茯苓中的铜含量 总被引:1,自引:0,他引:1
用硝酸-高氯酸混合酸(4∶1)消化鱼腥草、西洋参和茯苓,在波长324.8nm处,利用火焰原子吸收光谱法测定鱼腥草、西洋参和茯苓中铜的含量。线性回归方程为A=0.1708C 0.0004,相关系数r=0.9997,线性范围为0—5μg/mL,检出限为0.0035μg/mL,测定结果的相对标准偏差为0.09%,加标回收率为98.0%—104.2%。 相似文献
14.
Vartanyants IA Singer A Mancuso AP Yefanov OM Sakdinawat A Liu Y Bang E Williams GJ Cadenazzi G Abbey B Sinn H Attwood D Nugent KA Weckert E Wang T Zhu D Wu B Graves C Scherz A Turner JJ Schlotter WF Messerschmidt M Lüning J Acremann Y Heimann P Mancini DC Joshi V Krzywinski J Soufli R Fernandez-Perea M Hau-Riege S Peele AG Feng Y Krupin O Moeller S Wurth W 《Physical review letters》2011,107(14):144801
Measurements of the spatial and temporal coherence of single, femtosecond x-ray pulses generated by the first hard x-ray free-electron laser, the Linac Coherent Light Source, are presented. Single-shot measurements were performed at 780?eV x-ray photon energy using apertures containing double pinholes in "diffract-and-destroy" mode. We determined a coherence length of 17 μm in the vertical direction, which is approximately the size of the focused Linac Coherent Light Source beam in the same direction. The analysis of the diffraction patterns produced by the pinholes with the largest separation yields an estimate of the temporal coherence time of 0.55?fs. We find that the total degree of transverse coherence is 56% and that the x-ray pulses are adequately described by two transverse coherent modes in each direction. This leads us to the conclusion that 78% of the total power is contained in the dominant mode. 相似文献
15.
P. Skopintsev A. Singer J. Bach L. Müller B. Beyersdorff S. Schleitzer O. Gorobtsov A. Shabalin R. P. Kurta D. Dzhigaev O. M. Yefanov L. Glaser A. Sakdinawat G. Grübel R. Frömter H. P. Oepen J. Viefhaus I. A. Vartanyants 《Journal of synchrotron radiation》2014,21(4):722-728
A method to characterize the spatial coherence of soft X‐ray radiation from a single diffraction pattern is presented. The technique is based on scattering from non‐redundant arrays (NRAs) of slits and records the degree of spatial coherence at several relative separations from 1 to 15 µm, simultaneously. Using NRAs the spatial coherence of the X‐ray beam at the XUV X‐ray beamline P04 of the PETRA III synchrotron storage ring was measured as a function of different beam parameters. To verify the results obtained with the NRAs, additional Young's double‐pinhole experiments were conducted and showed good agreement. 相似文献