In inertial confinement fusion, quantitative and high-spatial resolution (Formula: see textm) measurements of the X-rays self-emitted by the hotspot are critical for studying the physical processes ...of the implosion stagnation stage. Herein, the 8 ± 0.39-keV monochromatic X-ray distribution from the entire hotspot is quantitatively observed in 5-Formula: see textm spatial resolution using a Kirkpatrick-Baez microscope, with impacts from the responses of the diagnosis system removed, for the first time, in implosion experiments at the 100 kJ laser facility in China. Two-dimensional calculations along with 2.5% P2 drive asymmetry and 0.3 ablator self-emission are congruent with the experimental results, especially for the photon number distribution, hotspot profile, and neutron yield. Theoretical calculations enabled a better understanding of the experimental results. Furthermore, the origins of the 17.81% contour profile of the deuterium-deuterium hotspot and the accurate Gaussian source approximation of the core emission area in the implosion capsule are clarified in detail. This work is significant for quantitatively exploring the physical conditions of the hotspot and updating the theoretical model of capsule implosion.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A cascade 3,3-sigmatropic rearrangement/aromatization strategy to the synthesis of 2-(3-methylbenzofuran-2-yl)phenol derivatives was developed and applied to the collective syntheses of seven ...2-arylbenzofuran-containing natural products, namely glycybenzofuran, glycyuralin E, lespedezol A1, puerariafuran, 7,2′,4′-trihydroxy-3-benzofurancarboxylic acid, coumestrol, and 4′-O-methylcoumestrol. Among them, the total syntheses of glycybenzofuran, glycyuralin E, puerariafuran, 7,2′,4′-trihydroxy-3-benzofurancarboxylic acid, and 4′-O-methylcoumestrol were reported for the first time. The practicality of this novel strategy in preparation of the key intermediates was demonstrated by performing the reaction on gram scale and by synthesizing a series of natural products with 2-(3-methylbenzofuran-2-yl)phenol scaffolds in a common strategy.
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IJS, KILJ, NUK, PNG, UL, UM
Abstract
Ternary Ag-In-S and quaternary Ag-In-Zn-S nanoparticles with different ratio of Ag/In/Zn/S are synthesized. The incorporation of Zn into Ag-In-S nanoparticles leads to the increase in the ...optical bandgap and the blue shift of photoluminescence (PL). The optical properties of these nanoparticles are significantly dependent on the chemical composition of nanoparticles. Time-resolved PL spectroscopy in nanosecond time regime is used to study the recombination processes of carriers, which involve the surface states and intrinsic crystallographic defects. These measurements support the donor-acceptor model, in which the PL is achieved by radiative recombination of the localized electron and hole.
A high-neutron yield platform imploded by a thin shell target is generally built to probe nuclear science problems, and it has the advantages of high neutron yield, ultrashort fusion time, micro ...fusion zone, isotropic and monoenergetic neutron. Some analytical models have been proposed to interpret exploding-pusher target implosion driven by a long wavelength laser, whereas they are imperfect for a 0.35 μm laser implosion experiment. When using the 0.35 μm laser, the shell is ablated and accelerated to high implosion velocity governed by Newton’s law, ablation acceleration and quasi-adiabatic compression models are suitable to explain the implosion of a laser direct-drive thin shell target. The new analytical model scales bang time, ion temperature and neutron yield for large variations in laser power, target radius, shell thickness, and fuel pressure. The predicted results of the analytical model are in agreement with experimental data on the Shenguang-III prototype laser facility, 100 kJ laser facility, Omega, and NIF, it demonstrates that the analytical model benefits the understanding of experiment performance and optimizing the target design of high neutron yield implosion.
In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical ...hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method.
A 100 kJ-level laser facility has been designed to study inertial confinement fusion physics in China. This facility incorporates various diagnostic techniques, including optical, x-ray imaging, ...x-ray spectrum, and fusion product diagnostics, as well as general diagnostics assistance systems and central control and data acquisition systems. This paper describes recent developments in diagnostics at the facility.
CsPbBr3 nanoparticles uniformly distributed on reduced graphene oxide (rGO) to form CsPbBr3/rGO nanocomposites are synthesized by a facile method. Their corresponding optical and X-ray photon ...response are investigated. UV–visible absorption spectra and photoluminescence measurements confirm that loading CsPbBr3 nanoparticles with an even distribution onto rGO surface can enhance the absorption and photon-generated carrier transportation. Thus, a significant enhancement in optical and X-ray photon response is demonstrated in CsPbBr3/rGO nanocomposites as compared with pure CsPbBr3 nanoparticles. Clear conductive switching phenomenon with a state conversion between “on” and “off” is also observed under the intermittent x-ray exposure. These results may provide a new potential application of CsPbBr3/rGO nanocomposites for X-ray photon detection.
•CsPbBr3 nanoparticles are uniformly distributed on reduced graphene oxide (rGO).•CsPbBr3/rGO nanocomposites could enhance photon-generated carrier transportation.•A significant enhancement of X-ray photon response was demonstrated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We report experimental research on laser plasma interaction (LPI) conducted in Shenguang laser facilities during the past ten years. The research generally consists of three phases: (1) developing ...platforms for LPI research in mm-scale plasma with limited drive energy, where both gasbag and gas-filled hohlraum targets are tested; (2) studying the effects of beam-smoothing techniques, such as continuous phase plate and polarization smoothing, on the suppression of LPI; and (3) exploring the factors affecting LPI in integrated implosion experiments, which include the laser intensity, gas-fill pressure, size of the laser-entrance hole, and interplay between different beam cones. Results obtained in each phase will be presented and discussed in detail.
The free-carrier dynamics and nonlinear refractive index in bulk polycrystalline diamond are investigated using a femtosecond ultraviolet-pump-optical-probe technique with a phase object. Normalized ...transmittances under open-aperture and closed-aperture conditions are simultaneously measured to determine the dynamics of nonlinear absorption and refraction in the sample. In the dynamics of nonlinear absorption, three processes are clearly observed: nondegenerate two-photon absorption, fast and slower decay components of the free-carrier dynamics. The lifetimes of the free carriers are precisely measured. In the dynamics of nonlinear refraction, we obtain the nonlinear refractive coefficient and find that the results obtained under the femtosecond regime differ from those of other semiconducting materials previously measured under the picosecond regime.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The first laser–plasma interaction experiment using lasers of eight beams grouped into one octad has been conducted on the Shenguang Octopus facility. Although each beam intensity is below its ...individual threshold for stimulated Brillouin backscattering (SBS), collective behaviors are excited to enhance the octad SBS. In particular, when two-color/cone lasers with wavelength separation 0.3 nm are used, the backward SBS reflectivities show novel behavior in which beams of longer wavelength achieve higher SBS gain. This property of SBS can be attributed to the rotation of the wave vectors of common ion acoustic waves due to the competition of detunings between geometrical angle and wavelength separation. This mechanism is confirmed using massively parallel supercomputer simulations with the three-dimensional laser–plasma interaction code LAP3D.
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