The velocity distribution of the hotspot in an inertial confinement fusion implosion changes the energy spectra of fusion neutrons emitted from the experiment as a function of viewing angle. These velocity-induced spectral changes affect the response of neutron activation diagnostics (NADs) positioned around the experiment and must be accounted for to correctly extract information about areal density () asymmetry from the data. Three mechanisms through which average hotspot velocity affects NAD activation are addressed: change in activation cross section due to the Doppler shift of the mean neutron energy, kinematic focusing of neutron fluence, and change in the scattering cross section due to the Doppler shift. Using the hotspot velocity inferred from neutron time-of-flight measurements of D-T and D-D fusion neutrons, the hotspot velocity is shown to account for the observed NAD activation asymmetry in a calibration shot with negligible fuel . A robust method to evaluate uncertainties in spherical-harmonic fits to the NAD data due to the velocity correction and detector uncertainty is discussed.
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http://dx.doi.org/10.1063/1.5038734 | DOI Listing |
Nat Commun
November 2024
College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
The Easter mantle plume has produced one of the longest hotspot tracks in the Pacific Ocean. While previous studies have focused on the eastern side extending across the Nazca Plate, we use Ar/Ar isotopic and geochemical data to investigate the less explored western side around the Easter Microplate. We propose a dynamic model in which a deeper (600 km-depth), less buoyant mantle exerts a westward force on the East Pacific Rise (EPR), while a more buoyant plume region drives Easter hotspot volcanism and a localised acceleration in seafloor spreading.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
Department of Earth and Planetary Sciences, University of California, Davis, CA 95616.
Ultrasonics
January 2025
School of Information Science and Technology, Fudan University, Shanghai 200433, China. Electronic address:
Chemosphere
October 2024
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China. Electronic address:
This study aimed to recover high-purity silica from hematite tailings (HTs) using superconducting high-gradient magnetic separation (S-HGMS) technology. This process involved converting silica into a silicone-rich concentrate and subsequently employing a fluorine-free mixed acid to leach the silicon-rich concentrate to remove impurities and achieve refinement and purification. The optimization of the S-HGMS process was conducted using the "Box-Behnken Design" method, resulting in the following optimal conditions: a pulp concentration of 50 g/L, a magnetic velocity ratio of 0.
View Article and Find Full Text PDFBiosens Bioelectron
November 2024
BioCIS, CNRS, Université Paris-Saclay, Orsay, 91400, France. Electronic address:
Surface-enhanced Raman Scattering (SERS) has become a powerful spectroscopic technology for highly sensitive detection. However, SERS is still limited in the lab because it either requires complicated preparation or is limited to specific compounds, causing poor applicability for practical applications. Herein, a micro-macro SERS strategy, synergizing polymer-assisted printed process with paper-tip enrichment process, is proposed to fabricate highly sensitive paper cartridges for sensitive practical applications.
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