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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Electrode erosion during high voltage vacuum breakdown measured by neutron activation analysis and gamma ray spectrometry, noting plasma formation from electrode material
Elemental composition and structure of metallic iron particles in lunar fines compared to meteorites, using neutron activation technique
Rare earth and trace element abundances for Apollo 11 lunar samples by neutron activation, comparing with Bruderheim chondrite and submarine basalts
Apollo 11 fines and rocks major and trace elements data obtained by combined instrumental and neutron activation analysis
Apollo 11 lunar, terrestrial and meteoritic basalts relationships, examining Ga, Ge, In, Ir and Au concentrations by neutron activation analyses
Neutron activation determined concentrations of Ni, Ga, Ge and Ir in iron meteorites with silicate inclusions
Neutron activation analysis of O, Si, Al, and Fe abundances in Apollo 12 lunar rock 12013
O, Si, Al and Fe abundances of Apollo 12 lunar rock 12013 from neutron activation analysis
Apollo 12 lunar rock 12013, discussing major and trace elemental abundances determination by neutron activation analysis
Neutron activation data on Zn, Ga, Ge, Cd, In and Ir trace elements for Apollo 12 lunar rock and soil sample
Apollo 12 specimens elemental abundance from neutron activation analysis, discussing fractional crystallization, partial melting, rare earth abundances and soil mixing model
Meteoritic material characterization from trace elements in Apollo lunar soil, core samples, breccia and anorthositic fragments by neutron activation analysis
Apollo 12 lunar soil, breccia and igneous rock samples, determining elemental abundances with spark source mass spectrometry and neutron activation analysis
Bulk elemental composition of Apollo 12 samples of lunar igneous and breccia rocks and soils from instrumental and radiochemical neutron activation analysis
Various radioisotope techniques were used as diagnostic tools for determining the performance of spacecraft propulsion feed system elements. Applications were studied in four tasks. The first two required experimental testing involving the propellant liquid oxygen difluoride (OF2): the neutron activation analysis of dissolved or suspended metals, and the use of radioactive tracers to evaluate the probability of constrictions in passive components (orifices and filters) becoming clogged by matter dissolved or suspended in the OF2. The other tasks were an appraisal of the applicability of radioisotope techniques to problems arising from the exposure of components to liquid/gas combinations, and an assessment of the applicability of the techniques to other propellants.
Neutron activation data on Zn, Ga, Ge, Cd, In and Ir are reported for six rocks and two soils from the Apollo 12 mission. Comparison of these and similar data for Apollo 11 samples indicates extralunar components in the 12070 and 10084 soils of about 1.0 and 1.1% expressed in terms of an assumed composition which is the same as the water-free portion of C1 chondrites. A relationship between the integrated flux of extralunar material and the increase in concentration of such material in the fines of the lunar regolith is derived. Apollo 12 rocks have concentrations of Zn, Ge, Cd, In and possibly Ir which are lower by factors of 60 or more, relative to terrestrial basalts. A mechanism is proposed for the late accretion of volatile-rich materials, including comets, in which a primitive terrestrial atmosphere is invoked to explain the significantly higher concentrations of such substances on the earth.
The chemical abundances were measured by instrumental and radiochemical neutron activation analysis in a variety of lunar specimens. Apollo 14 soils are characterized by significant enrichments of Al2O3, Na2O and K2O and depletions of TiO2, FeO, MnO and Cr2O3 relative to Apollo 11 and to most of Apollo 12 soils. The uniform abundances in 14230 core tube soils and three other Apollo 14 soils indicate that the regolith is uniform to at least 22 cm depth and within approximately 200 m from the lunar module. Two Luna 16 breccias are similar in composition to Luna 16 soils. Four Apollo 15 soils (LM, STA 4, 9, and 9a) have variable compositions. Interelement correlations between MnO-FeO, Sc-FeO, V-Cr2O3 and K2O-Hf negate the hypothesis that howardite achondrites may be primitive lunar matter, argue against the fission hypothesis for the origin of the moon, and precludes any selective large scale volatilization of alkalies during lunar magmatic events.