Using spherically bent crystals for obtaining high-resolution, large-field, monochromatic X-ray backlighting imaging for wide range of Bragg angles

The new advantages of well-known combination of a laser-produced X-ray plasma source and spherically bent crystal for the soft X-ray region backlighting scheme were experimentally demonstrated and theoretically modelling by ray-tracing package SHADOW. The X-ray source was produced by heating radiation of Ti:Sa laser (120 fs, 3-5 mJ, laser flux density 10¹⁶ W/cm²) or XeCl laser (1-1.3 J, 10 ns, laser flux density 10¹³ W/cm²) with repetition 10 Hz at different solid targets (Mg, Fe, Ni, Dy, BaF₂). X-ray source spot size on the target was well localized both spatially (approximately 20 μm) and temporally (1 ps - 10 ns, depend of used laser) and is spectrally tunable in a relatively wide range (6-19 angstroms). High quality monochromatic (δλ/λ to approximately 10^-5-10^-3) images with high spatial resolution (up to approximately 4 μm) and in a large field of view (few mm) were obtained for different wavelengths using the same spherically bent crystal. It was demonstrated at first time that the spherically bent crystals can be sufficiently used for obtaining high-resolution, large-field, monochromatic images in a wide range of Bragg angles (θ = 40-90°), thus spherically bent crystals are universal for very wide wavelength selection, what is very important for many applications. Obtained experimental results were independently confirmed by ray-tracing modelling for different radius of crystal curvatures, Bragg angles and linear magnification of images.