Enhancement of x-ray sources from laser-produced plasmas is significant in wide-ranging applications. Solid and foam TiO2 targets were both used to generate bright x-ray sources at the Shenguang-III ...prototype laser facility, with a total laser power of 3.2 TW. The new foam targets were with an ultra-low initial density of 8.1 mg/cm3 and a high Ti fraction of 33 sat. %. By absolute measurements, the multi-keV x rays of the 4 keV–7 keV band and 1.6 keV–4.4 keV band and the total x rays above 0.1 keV of the foam target have simultaneously shown conversion enhancements of 1.4, 3.1, and 2.3 times, respectively, compared with the solid target. A much larger emission volume and an average electron temperature of 3.2 keV by moving the foci of laser beams inner were obtained for the foam target, providing a good condition for multi-keV x-ray production.
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.
Two neutron time-of-flight (nToF) detectors have been employed to measure the neutron time-of-flight spectrum in different lines-of-sight, i.e., at the equator plane and the south pole, on ...Shenguang-III (SG-III) laser facility. The contribution of scattered neutrons has been calculated with the Monte Carlo code JMCT for each nToF detector. The results show that the scattered neutron spectrum is dominated by neutrons scattered on materials in the experiment hall, including the vacuum chamber. The shape of the scattered neutron spectrum depends on the view line, which has been observed with nToF detectors located in the experiment hall of the SG-III laser facility. A method based on the convolution of the calculated neutron time-of-flight spectrum and the instrument response function has been developed for the ion temperature determination. The calculated neutron spectra with the contribution of scattered neutrons can fit the measured results. No obvious ion temperature anisotropy has been observed on the SG-III laser facility at present.
•X-ray emissions of laser produced Au foam plasmas are investigated.•X-ray spectral characteristics and conversion efficiency are measured.•Experimental and theoretical spectral distributions agree ...with each other.
The X-ray emission properties of Au plasmas consist of spectral distribution, M band fraction (2–4keV), X-ray angular distribution and X-ray conversion efficiency, are imperative for various X-ray source applications. In order to investigate the X-ray emission properties of laser produced plasmas with Au and Au foam targets, experiments were carried out in Shenguang II laser facility. Au foam targets with densities of 0.6 and 0.4g/cm3 were employed. The X-ray emission properties were measured. Excellent agreements of the experimental and theoretical spectral distributions and M band fractions were achieved.
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Thousand Seed Weight （TSW） is one of the major yield components of rapeseed （Brassica napus L.）. Here reports an extra-large seed germplasm GM01 which was obtained through isolated microspore ...culture. Three-way cross was made： H8--a Yunnan spring early-maturing rapeseed variety, ＂Legeney＂--a Canadian canola variety and ＂020010＂--a semi-winter late-maturing rapeseed variety. One hundred and forty eight doubled hyploid lines were obtained from the F~ plants of three-way cross through isolated mierospore culture. Among them, the TSW of GM01 amounted to 8.68 g and the TSW of 53 lines were above 5.0 g. The TSWs of GM01 were relatively stable among the multi-location field trials from 2007 to 2014 with variation being only 10%-15% among the locations and years. Compared with H8, GM01 had larger flowers, stigmas, siliques and seed diameters, but less branches, siliques per plant and seeds per silique.
Abstract
To achieve ignition in a laboratory via inertial confinement fusion, a spherical capsule containing a frozen layer of deuterium and tritium (DT) fuel will be imploded on an MJ-class laser ...facility. However, if pure deuterium fuel can be used in place of DT fuel for tuning shots, we may speed up the process of ignition experiments while maintaining the surrogacy by significantly reducing the level of radioactivity. Unfortunately, it has long been assumed that neither the approach of symmetrical infrared irradiation used in the Omega direct-drive experiments nor the method of beta-layering used in the NIF experiments can be used to smooth the D layered capsule in cylindrical hohlraums. The difficulty in smoothing the D ice layer prevents us from taking advantage of cryogenic D-layered capsules in indirect-drive experiments. In this work, we established a procedure to form a uniform D-ice layer for capsules held in cylindrical hohlraums and carried out indirect-drive cryogenic D-layered implosion experiments using a squared laser pulse on the Shenguang Laser Facility in China. The quality of the D ice layer is characterized by phase-contrast imaging. The root-mean-square of the power spectrum in modes 2–100 is about 2.2
μ
m. The implosion performance of the D-layered capsules is close to the prediction of one-dimensional simulations. The measured neutron yield and areal fuel density are 1.2 × 10
11
and 80 mg cm
−2
, respectively.
The ultrastable encrypted storage of X-ray image with quantitative and ultrahigh-spatial resolution are crucial for a wide range of applications in radiation imaging, and it can be achieved by using ...the radio-photoluminescence (RPL) material, Ag-doped phosphate glass (Ag-PG), which was fabricated via the melt-quenching method. Under X-ray irradiation, Ag-PG produces a luminescence center, obvious 650 nm emission peak, which can be repeatedly excited by ultraviolet light without intensity attenuation. Quantitative X-ray image storage was realized based on the linear relationship between RPL intensity and X-ray irradiation time. X-ray image with a submicron spatial resolution of 0.7 µm was achieved, which could be stably stored without attenuation for more than 300 days. This submicron level X-ray image can be written into the Ag-PG as an encrypted information, and can only be visualized by an ultraviolet light. Additionally, heat treatment (400 °C for 2 h) could eliminate the influence of X-ray radiation on the Ag-PG, and restore the state of the Ag-PG before X-ray irradiation, which allows the recyclability and reusability of the Ag-PG. This research is of great significance for promoting the encrypted storage of X-ray images based on Ag-PG or other RPL materials.
•The study demonstrated the ultrahigh-spatial-resolution and ultrastable X-ray image storage and encryption through Ag-PG.•The X-ray imaging at submicron scale is realized by using the Ag-PG, which could be stably stored for more than 300 days.•Ag-PG further realizes the anti-counterfeiting and encryption of X-ray image information with sub-micron level.•The Ag-PG exhibits important application potential in 3D X-ray imaging.
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The new hohlraum experimental platform and the quasi-3D simulation model are developed to enable the study of the indirect drive experiment using the six-cylinder-port hohlraum for the first time. It ...is also the first implosion experiment for the six laser-entrance-hole hohlraum to effectively use all the laser beams of the laser facility that is primarily designed for the cylindrical hohlraum. The experiments performed at the 100 kJ Laser Facility produce a peak hohlraum radiation temperature of ∼222 eV for ∼80 kJ and 2 ns square laser pulse. The inferred x-ray conversion efficiency η∼87% is similar to the cylindrical hohlraum and higher than the octahedral spherical hohlraum at the same laser facility, while the low laser backscatter is similar to the outer cone of the cylindrical hohlraum. The hohlraum radiation temperature and M-band (>1.6 keV) flux can be well reproduced by the quasi-3D simulation. The variations of the yield-over-clean and the hot spot shape can also be semiquantitatively explained by the calculated major radiation asymmetry of the quasi-3D simulation. Our work demonstrates the capability for the study of the indirect drive with the six-cylinder-port hohlraum at the cylindrically configured laser facility, which is essential for numerically assessing the laser energy required by the ignition-scale six-cylinder-port hohlraum.
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