RESUMO
A diagnostic for extreme ultraviolet spectroscopy was fielded on the sheared-flow-stabilized (SFS) fusion Z-pinch experiment (FuZE-Q) for the first time. The spectrometer collected time-gated plasma emission spectra in the 5-40 nm wavelength (30-250 eV) range for impurity identification, radiative power studies, and for plasma temperature and density measurements. The unique implementation of the diagnostic included fast (10 ns risetime) pulsed high voltage electronics and a multi-stage differential pumping system that allowed the vacuum-coupled spectrometer to collect three independently timed spectra per FuZE-Q shot while also protecting sensitive internal components. Analysis of line emission identifies oxygen (N-, C-, B-, Be-, Li-, and He-like O), peaking in intensity shortly after maximum current (>500 kA). This work provides a foundation for future high energy spectroscopy experiments on SFS Z-pinch devices.
RESUMO
The sheared-flow stabilized Z pinch has demonstrated long-lived plasmas with fusion-relevant parameters. We present the first experimental results demonstrating sustained, quasi-steady-state neutron production from the fusion Z-pinch experiment, operated with a mixture of 20% deuterium/80% hydrogen by pressure. Neutron emissions lasting approximately 5 µs are reproducibly observed with pinch currents of approximately 200 kA during an approximately 16 µs period of plasma quiescence. The average neutron yield is estimated to be (1.25±0.45)×10^{5} neutrons/pulse and scales with the square of the deuterium concentration. Coincident with the neutron signal, plasma temperatures of 1-2 keV and densities of approximately 10^{17} cm^{-3} with 0.3 cm pinch radii are measured with fully integrated diagnostics.
RESUMO
Molecular genetic analysis of ancient human remains are mostly based on mitochondrial DNA due to its better preservation in human skeletons in comparison with nuclear DNA. We investigated mtDNA extracted from human skeletons found in graves in Yakutia to determine their haplotypes and to compare them with lineages of modern populations. Ancient DNA was extracted from fragments of three skeletons of Yakut graves at At-Dabaan, Ojuluun and Jaraama sites (dating XVIII century) and two skeletons of Neolithic graves at Kerdugen site found in central Yakutia (Churapchinsky, Kangalassky and Megino-Kangalassky districts of Yakutia). Five different haplotypes belonging to specific Asian haplogroups were identified. Lineages of mtDNA of Yakut graves belong to haplo-groups C4a, D5a2 and B5b. Our results indicate the continuity of mitochondrial lineages in the Yakut gene pool during the last 300 years. Haplotypes of two humans from Kerdugen site graves belong to haplogroups A4 and G2a/D. We compared these haplotypes with that of 40,000 Eurasian individuals, 900 of them from Yakutia. No exact matches were found in Paleoasian populations of Chukchi, Eskimos, Koryaks and Itelmen. Phylogenetically close haplotypes (+/- 1 mutation) were found in populations of Yakuts and Evenks, as well as in some populations of China, Southern and Western Siberia.
