Multi-filament structures produced by vortical high-power femtosecond pulses propagating through clouds and fog can simultaneously clear two channels with cylindrical and annular profile. We present ...a method to achieve Free Space Optical (FSO) communications through such highly scattering media by propagating appropriately shaped laser modes through these channels. As a proof of concept, we implemented a Laguerre-Gaussian beam as information signal carrier to demonstrate transmission of 543-nm CW laser beam through a 1-m long cloud chamber using both channels. The low power of the information signal in this experiment allows considering applications in Earth-satellite FSO communication.
The corrosive environment provided by chlorine ions on the welds of stainless steel dry cask storage canisters for used nuclear fuel may contribute to the occurrence of stress corrosion cracking. We ...demonstrate the use of fiber-optic laser-induced breakdown spectroscopy (FOLIBS) in the double-pulse (DP) configuration for high-sensitivity, remote measurement of the surface concentrations of chlorine compatible in constrained space and challenging environment characteristic for dry cask storage systems. Chlorine surface concentrations as low as 5mg/m2 have been detected and quantified by use of a laboratory-based and a fieldable DP FOLIBS setup with the calibration curve approach. The compact final optics assembly in the fieldable setup is interfaced via two 25-m long optical fibers for high-power laser pulse delivery and plasma emission collection and can be readily integrated into a multi-sensor robotic delivery system for in-situ inspection of dry cask storage systems.
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•Demonstrated DP FOLIBS can achieve high sensitivity in direct Cl measurement.•Developed compact fieldable setup of DP FOLIBS for on-site deployment.•Constructed LIBS calibration curves for Cl (5–100mg/m2) on steel.
There is an urgent need for new, better instrumentation and techniques for detecting and characterizing special nuclear material (SNM), i.e., highly enriched uranium and plutonium. The development of ...improved instruments and techniques requires experiments performed with the SNM itself, which is of limited availability. This paper describes the findings of experiments performed at the National Criticality Experiments Research Center conducted using new instruments and techniques on unclassified, kg-quantity SNM objects. These experiments, performed in the framework of the Department of Energy, National Nuclear Security Administration Consortium for Monitoring, Technology, and Verification, focused on detecting, characterizing, and localizing SNM samples with masses ranging from 3.3 to 13.8 kg, including plutonium and highly enriched uranium using prototype detectors and techniques. The work demonstrates SNM detection and characterization using recently-developed prototype detection systems. Specifically, we present new results in passive detection and imaging of plutonium and uranium objects using gamma-ray and dual particle (fast neutron and gamma-ray) imaging. We also present a new analysis of the delayed neutron emissions during active interrogation of uranium using a neutron generator.
Structured intense laser beams offer degrees of freedom that are highly attractive for high-field science applications. However, the performance of high-power laser beams in these applications is ...often hindered by deviations from the desired spatiotemporal profile. This study reports the wavefront optimization of ultrafast Laguerre-Gaussian beams through the synergy of adaptive optics and genetic algorithm-guided feedback. The results indicate that the intensity fluctuations along the perimeter of the target ring-shaped profile can be reduced up to ∼15%. Furthermore, the radius of the ring beam profile can be tailored to a certain extent by establishing threshold fitting criteria. The versatility of this approach is experimentally demonstrated in conjunction with different focusing geometries.
•We investigated effect of inorganic and organic selenium on stud boars’ fertility.•The supplementation of both inorganic and organic selenium affected semen quality.•Organic selenium improved ...spermatozoa progressive motility and resistance the most.•The storage ability of semen was improved by organic selenium supplementation.•The highest fertility rate was recorder in organic selenium supplemented studs.
The aim of this study was to determine how dietary supplementation of inorganic and organic selenium affects the selenium concentration and glutathione peroxidase activity in blood and sperm of sexually mature stud boars. Twenty-four boars of the Large White, Landrace, Pietrain and Duroc breeds of optimal breeding age (on average 2.5 years old) were used. The study lasted 90 days. The boars were randomly assigned to one of three dietary treatment groups: T1=control; no added selenium (n=8 boars), T2=added 0.3ppm inorganic selenium (sodium selenite, Microgran® Se 1% BMP) (n=8 boars), and T3=added 0.3ppm organic selenium (Se-yeast, Sel-Plex 2000®) (n=8 boars). The concentration of selenium was determined in whole blood and semen, while the activity of glutathione peroxidase (GPx) was measured in blood plasma and semen. In order to measure GPx activity in semen, reactivation of the enzymatic GPx activity was performed. The determined selenium concentration in blood was lowest in the non-supplemented group of boars. Blood plasma GPx activity was higher in boars fed organic selenium than in boars fed a diet without supplemented selenium. While the supplementation of sodium selenite significantly increased GPx activity in boar semen. The highest-concentration of selenium in semen at the end of the trial was determined in the group of boars supplemented with organic selenium, somewhat lower in boars fed supplemented inorganic selenium, and the lowest in the non-supplemented group of boars. The only significant difference between the selenite and Se-yeast diet supplementation was observed in the Se concentration of the semen. The supplementation of selenium affected semen quality, and organic selenium improved the progressive motility of the spermatozoa and increased their resistance in hypo-osmotic and thermal tests. The storage ability of short term preserved semen was improved by organic selenium supplementation, as well as also increasing the fertility rate in gilts.
We demonstrate a novel single-shot method to determine the detonation energy of laser-induced plasma and investigate its performance. This approach can be used in cases where there are significant ...shot-to-shot variations in ablation conditions, such as laser fluctuations, target inhomogeneity, or multiple filamentation with ultrashort pulses. The Sedov blast model is used to fit two time-delayed shadowgrams measured with a double-pulse laser. We find that the reconstruction of detonation parameters is insensitive to the choice of interpulse delay in double-pulse shadowgraphy. In contrast, the initial assumption of expansion dimensionality has a large impact on the reconstructed detonation energy. The method allows for a reduction in the uncertainties of blast wave energy measurements as a diagnostic technique employed in various laser ablation applications.
This study employs laser ablation (LA) to investigate mechanisms for U optical signal variation under various environmental conditions during laser absorption spectroscopy (LAS) and optical emission ...spectroscopy (OES). Potential mechanisms explored for signal quenching related to ambient conditions include plasma chemistry (e.g., uranium oxide formation), ambient gas confinement effects, and other collisional interactions between plasma constituents and the ambient gas. LA-LAS studies show that the persistence of the U ground state population is significantly reduced in the presence of air ambient compared to nitrogen. LA-OES yields congested spectra from which the U I 356.18nm transition is prominent and serves as the basis for signal tracking. LA-OES signal and persistence vary negligibly between the test gases (air and N2), unlike the LA-LAS results. The plume hydrodynamic features and plume fundamental properties showed similar results in both air and nitrogen ambient. Investigation of U oxide formation in the laser-produced plasma suggests that low U concentration in a sample hinders consistent detection of UO molecular spectra.
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•Significant reduction in U absorption persistence in air compared to nitrogen•Explored plasma chemistry leading to U absorption signal quenching•Compared absorption and emission spectroscopy of U transitions•Plume hydrodynamics and plasma fundamentals showed similar behavior in both gases
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