Uniformity of the soft-x-ray emissions from gold foils irradiated by OMEGA laser beams determined by a two-mirror normal-incidence microscope with multilayer coatings

摘要

A two-mirror normal-incidence microscope with multilayer coatings was used to image the soft-x-ray-emissions from planar foils irradiated by OMEGA laser beams. The bandpass of the multilayer coatings was centered at a wavelength of 48.3 Angstrom (257-eV energy) and was 0.5 Angstrom wide. Five overlapping OMEGA beams, without beam smoothing, were typically incident on the gold foils. The total energy was 1500 J, and the focused intensity was 6 x 10(13) W cm(-2). The 5.8x magnified images were recorded by a gated framing camera at various times during the 3-ns laser pulse. A pinhole camera imaged the x-ray emission in the energy range of >2 keV. On a spatial scale of 10 mu m, it was found that the soft-x-ray; images at 257 eV were quite uniform and featureless. In contrast, the hard-x-ray images in the energy range of >2 keV were highly nonuniform with numerous features of size 150 mu m. [References: 12]