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

T. A. Pikuza, A. Ya. Faenova , M. Fraenkelb , A. Ziglerb, F. Florac, S.Bollantic,
 P.Di Lazzaroc, T. Letardic, A. Grillid, L.Palladinoe, G. Tomassettie, A. Realee, L. Realee, A. Scafatie, T. Limongie, F. Bonfiglif, L.Alainellig,  M.Sanchez del Riog

a Multicharged Ions Spectra Data Center of VNIIFRTI, Mendeleevo, Moscow Region, 141570, Russia
b Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
c ENEA, Dipartimento Innovazione, Settore Fisica Applicata, 00044 Frascati, Italy
d INFN Frascati, 00044 Frascati, Italy
e INFM Dipartamento di Fisica dell'Aquila and LNGS-INFN, Assergi (L'Aquila), Italy
f EL.EN. S.p.A., Calenzano (FI), Italy
gEuropean Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France


Abstract
The Shadow Monochromatic Backlighting (SMB) scheme, a modification of the well-known soft X-ray monochromatic backlighting scheme, is proposed. It is based on a spherical crystal as the dispersive element and extends the traditional scheme by allowing working with a wide range of Bragg angles and therefore with a wide spectral range. The advantages of the new scheme are demonstrated experimentally and supported numerically by ray-tracing simulations. In the experiments, the X-ray backlighter source is a laser-produced plasma, created by the interaction of ultra short pulse, Ti:Sapphire laser (120 fs, 3-5 mJ, 1016 W/cm2 on target) or short wavelength XeCl laser (10 ns, 1-2 J, 1013 W/cm2 on target) with various solid targets (Dy, Ni+Cr, BaF2). In both experiments, the X-ray sources are well localized both spatially (~20 mm) and are spectrally tunable in a relatively wide wavelengths range (l=8-15 Å). High quality monochromatic (dl¤l~10-5-10-3) images with high spatial resolution (up to ~4 mm) over a large fieldof view (few mm2) were obtained. Utilization of the spherically bent crystals for obtaining high-resolution, large field, monochromatic images in a wide range of Bragg angles (35°<Q<90°) is demonstrated for the first time.