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

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 one to work with a wide range of Bragg angles and thus in 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 an ultrashort pulse, Ti:Sapphire laser (120 fs, 3–5 mJ, 1016 W/cm2 on target) or a 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 spatially (∼20 μm) and are spectrally tunable in a relatively wide wavelength range (λ = 8–15 Å). High quality monochromatic (δλ/λ ∼ 10−5–10−3) images with high spatial resolution (up to ∼4 μm) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35° < Θ < 90°) is demonstrated for the first time

X-ray radiation from ions with K-shell vacancies

Abstract New types of space resolved X-ray spectra produced in light matter experiments with high intensity lasers have been investigated experimentally and theoretically. This type of spectra is characterised by the disappearance of distinct resonance line emission and the appearance of very broad emission structures due to the dielectronic satellite transitions associated to the resonance lines. Atomic data calculations have shown, that rather exotic states with K-shell vacancies are involved. For quantitative spectra interpretation we developed a model for dielectronic satellite accumulation (DSA-model) in cold dense optically thick plasmas which are tested by rigorous comparison with space resolved spectra from ns-lasers. In experiments with laser intensities up to 10 19 W/cm 2 focused into nitrogen gas targets, hollow ion configurations are observed by means of soft X-ray spectroscopy. It is shown that transitions in hollow ions can be used for plasma diagnostic. The determination of the electron temperature in the long lasting recombining regime is demonstrated. In Light-matter interaction experiments with extremely high contrast (up to 10 10 ) short pulse (400 fs) lasers electron densities of n e ≈3×10 23 cm −3 at temperatures between kT e =200–300 eV have been determined by means of spectral simulations developed previously for ns-laser produced plasmas. Expansion velocities are determined analysing asymmetric optically thick line emission. Further, the results are checked by observing the spectral windows involving the region about the He α -line and the region from the He β -line to the He-like continuum. Finally, plasmas of solid density are characteristic in experiments with heavy ion beams heating massive targets. We report the first spectroscopic investigations in plasmas of this type with results on solid neon heated by Ar-ions. A spectroscopic method for the determination of the electron temperature in extreme optically thick plasmas is developed

x ray imaging of bio medical samples using laser plasma based x ray sources and lif detector

This contribution to ECPD2019 is dedicated to the memory of Anatoly Faenov. During a period of approximately thirteen years 1994–2006, Anatoly and his wife Tatiana Pikuz (simply "Tania" for friends), accepting the frequent invitations of the National Institute for Nuclear Physics (INFN) and of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), cooperated with many Italian research laboratories dedicated to EUV and soft X-ray generation, spread in different towns (L'Aquila, Frascati, Milano, Padova, Pisa, Roma, etc.). In spite of the fact that they could stay in Italy only about one or two months per year, their activity was so intense that more than 50 peer- reviewed publications were generated from their experimental and theoretical work (just considering only the results obtained at L'Aquila and Tor Vergata—Rome Universities and at the ENEA Research Center of Frascati), without mentioning the cultural atmosphere that they stimulated in the field of Science and Humanity. The numerous experimental spectra obtained at ENEA by means of their spherically bent mica spectrometers, together with the corresponding theoretical simulations performed in Moscow, allowed to study the changing role of different excitations mechanisms for various plasma conditions, and to characterize at best the ENEA laser-plasma source for different applications: polychromatic and monochromatic micro-radiography of dried biological samples at 1 keV, soft X-ray contact microscopy (SXCM) of living cells in the water-window spectral region, spectroscopy of hollow atoms, etc. In this memorial paper, the main results of biological samples imaging on lithium fluoride (LiF) detectors, obtained with the ENEA and Tor Vergata University laser-plasma sources, are presented. In particular, the improvement of the micro-radiography and of the SXCM techniques obtained after moving from photoresist detectors and photographic films to lithium fluoride (LiF) detectors are discussed, for both dried and wet biological samples

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

Large-field high resolution X-ray monochromatic microscope, based on spherical crystal and high-repetition-rate laser-produced plasmas

The combination of a table-top laser produced plasma X-ray source and spherically bent crystals for the soft X-ray region is used in traditional X-ray microscopy schemes. The X-ray source is well localized both spatially (approximately 20 μm) and temporally (1 ps-10 ns, it depends on the used laser) and it 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) are presented. For many applications, these low-cost compact systems can offer a simple alternative to the larger installations which are usually used. It was demonstrated that the spherically bent crystals can be efficiently used in a wide (θ = 40-90°) range of reflection angles, thus allowing a wide wavelength selection. A very efficient concentration of monochromatic X-Ray radiation into different spot shapes (line, circle spot, etc) is demonstrated

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

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 one to work with a wide range of Bragg angles and thus in 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 an ultrashort pulse, Ti:Sapphire laser (120 fs, 3-5 mJ, 1016 W/cm2 on target) or a short wavelength XeCl laser (10 ns, 1-2 J, 1013W/cm2 on target) with various solid targets (Dy, Ni + Cr, BaF2). In both experiments, the X-ray sources are well localized spatially (∼20 μm) and are spectrally tunable in a relatively wide wavelength range (λ = 8-15 Å). High quality monochromatic (δλ/λ ∼ 10-5-10-3) images with high spatial resolution (up to ∼ 4 μm) over a large field of view (a few square millimeters) were obtained. Utilization of spherically bent crystals to obtain high-resolution, large field, monochromatic images in a wide range of Bragg angles (35° < Θ < 90°) is demonstrated for the first time

Applications des plasmas produits par le laser à excimères HERCULES-L : du recuit du silicium à la lithographie par rayons X

Un laser à excimères de grand volume, HERCULES-L, a été développé dans le cadre d'un programme européen pour des applications industrielles concernant le traitement de surface du silicium et la génération de plasmas par laser. Les performances de ce laser sont particulièrement adaptées pour le traitement de grandes surfaces et pour la création de photons EUV (hv ~ 100 eV) par plasma assisté par laser