Shadow monochromatic backlighting: Large-field high resolution X-ray shadowgraphy with improved spectral tunability

The shadow monochromatic backlighting (SMB) scheme, a modification of the w ell-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the trad itional scheme by allowing one to work with a wide range of Bragg angles an d thus in a wide spectral range. The advantages of the new scheme are demon strated experimentally and supported numerically by ray-tracing simulations . In the experiments, the X-ray backlighter source is a laser-produced plas ma, created by the interaction of an ultrashort pulse, Ti:Sapphire laser (1 20 fs, 3-5 mJ, 10(16) W/cm(2) on target) or a short wavelength XeCl laser ( 10 ns, 1-2 J, 10(13) W/cm(2) on target) with various solid targets (Dy, Ni + Cr, BaF2). In both experiments, the X-ray sources are well localized spat ially (similar to 20 mum) and are spectrally tunable in a relatively wide w avelength range (lambda = 8-15 Angstrom). High quality monochromatic (delta lambda/lambda similar to 10(-5)-10(-3)) images with high spatial resolutio n (up to similar to4 mum) over a large field of view (a few square millimet ers) were obtained. Utilization of spherically bent crystals to obtain high -resolution, large field, monochromatic images in a wide range of Bragg ang les (35 degrees < Theta < 90 degrees) is demonstrated for the first time.