X-Ray Spectromicroscopy of 120-fs Laser-Produced Plasma

摘要

X-ray spectra of various plasma microsources can be recorded simultaneously with spectral and spatial resolution using spectrograph with flat, convex or concave crystals and a slit placed parallel to the dispersion direction (see, for example, [1, 2]). This approach is simple for realization, but the obtained spatial resolution is limited by the slit size. The slit size is usually not smaller than 20-30 μm, due to the dramatic reduction of the system throughput. High spatial resolution (below 10 μm) combined with relatively high throughput was obtained using a shadow technique [21]. A substantial improvement of spatial resolution (4-10 μm) has been achieved through the use of the crystals bent to a complex surfaces (such as, for example, sphere or tori or elliptically [3-10]). Further improvement of the spatial resolution toward achievement of the micron to the submicron level has been pursued using Fresnel structures such as transmission zone plates. However, the spectral resolution obtained by this approach is very limited.